Our local cosmic terrain (Credit: Helene Courtois)

A new video tours the nearby universe and makes it charmingly familiar.

When I was a graduate student I spent a lot of time studying maps of our universe. These were being constructed using great surveys of galaxies. Each of these fuzzy specks was triangulated on the sky and located in depth by its apparent recession velocity – the phenomenon of universal expansion first measured by astronomers like Edwin Hubble back in the 1930′s. One of my favorite references was an atlas published, rather unusually, in book form by Brent Tully and Richard Fisher in 1987. This took the dry tabulations of galaxy positions and apparent distances and made them into pictures, real maps, with regions and features labeled and made familiar.

I still have it:

The Nearby Galaxy Atlas (Tully & Fisher, Cambridge University Press, 1987)

Here, for example, are positions of our neighboring galaxies towards the northern galactic pole:

Galaxies fit for an ancient explorer...

It was a rather bold thing to do, to produce these maps, since we knew that our knowledge was still very limited. But what a marvelous thing, to be able to hold an atlas of the universe in your hands!

Time moves on, and now surveys like the great Sloan Digital Sky Survey, or the 2dF and 6dF projects, have fleshed out and extended these earlier efforts by astonishing factors. But there is still something deeply moving about charting out our cosmic neighborhood, whether its really a backwater or a main street. It’s our place in the vastness of nature, and in that sense it will forever be unique.

This new video tour, the ‘Cosmography of the Local Universe‘ by Helene Courtois et al. gathers together our current atlas in a charming and fascinating tutorial.

It’s well worth the 17 minutes to feel a little like a cosmic mariner. And in case you wonder how ‘local’ is local? This map encompasses galaxies up to around 400 million light years from us…

A better quality (to HD) video is also available here:

Cosmography of the Local Universe from Daniel Pomarède on Vimeo.

For more information check out the project page and the link to the preprint of the scientific article to appear in the Astronomical Journal, by Helene M. Courtois, Daniel Pomarede, R. Brent Tully, Yehuda Hoffman, and Denis Courtois.

Oh well. All I can say is that normal service will be resumed as soon as possible. Which will be a good thing, because a huge number of interesting and intriguing discoveries and stories have emerged over the past couple weeks. From stronger support for the observation of ancient stream beds on Mars, to a remarkable opportunity for planets around Proxima Centauri, to 3 billion year old plankton, to evidence that hot Jupiters may not get consumed by their parent stars as often as we thought.

My excuse for not doing better (‘sorry, but a giraffe ate my homework, again’) is that I’ve had a rather packed schedule. It started about ten days ago when John Matson of Scientific American and I had a lot of fun talking to the Daily Circuit on Minnesota Public radio about cosmic origins and the meaning of it all. You can listen to this lengthy interview here. You can even see us doing it panorama-style in Washington Square Park, New York.

Then this happened while I was helping coach my daughter’s soccer team on a Sunday afternoon:

These amazing kids knew what they were talking about, informed, insightful. Perhaps there is hope for the species after all?

Somewhere along the line I also popped into Scientific American to record some answers to viewers questions for the Sci Am SpaceLab channel on YouTube . The topics ranged from gamma rays and black holes to cosmic expansion and gravitational collapse of rotating structures…you can judge for yourselves:

The MPA in Germany

I then had to stagger (nursing a head cold from one of those evolutionary marvels we call a virus) onto a plane to fly eastwards to the lovely city of Munich and the out-burb of Garching, home to many scientific and technological wonders, including the Max-Planck-Institut für Astrophysik (“MPA”), where I gave a joint colloquium with the European Southern Observatories on “Epic Astrobiology”.

It was fun, except I had to fly back less than 48 hours later. Still, wandering around the Bavarian countryside was exceedingly nice, where one bumps into some intriguing things among the wheat fields:

As if from the future, a quantum optics center rises from the leafy surroundings in Garching...(C. Scharf)

The home of the European Southern Observatories - the UN of astronomy? (C. Scharf)

If you want to actually watch my talk, it was recorded by the good people at ESO and you can find it on their June talk web-page – down at the bottom here.

Epic Astrobiology, a talk at MPA/ESO June 6th 2013

A sum total of two days on the ground in Germany and it was back on a plane to land in NYC just as tropical Storm Andrea was in full swing.

My crowning achievement of it all? I’d like to say it was scientific exchange – which was indeed most excellent – but the best thing of all was discovering a new potential cure for jetlag.

Captured June 5th, what the doctor ordered for cosmic angst and fatigue (C. Scharf)

And that was my week.

Glowing hydrogen and a stellar birthplace 6,500 light years away (ESO/VLT)

Fifteen years ago the European Southern Observatory, a consortium of 15 member states, started scientific operations with the Very Large Telescope (VLT) on Cerro Paranal in the Chilean Atacama desert. The VLT is a beast of an observatory, to put it mildly.

The VLT in all its glory - spot the human to the extreme left (ESO/VLT)

Four 8.2 meter diameter mirrors are housed in domes that would put most single mirror observatories to shame, and they’re complemented by four 1.8 meter diameter movable telescopes that can be utilized for optical interferometry – a technique to significantly improve the resolving power of the observatory for bright objects.

Often though, visiting astronomers only make use of the individual 8.2 meter instruments – each on its own is an enormous light gathering bucket capable of detecting some of the faintest, and most distant, objects in our observable universe.

These great telescopes also have Mapuche names: Antu (The Sun), Kueyen (The Moon), Melipal (The Southern Cross), and Yepun (The evening star – Venus).

The above image of a stellar nursery was chosen to help celebrate the fifteen years of operation of the VLT observatory, and its extraordinary discoveries. The nursery has a rather dull name of IC 2944, but it’s a beautiful place. Intense light from young stars is ionizing hydrogen gas, stripping electrons from protons, and as the hydrogen ensnares new electrons it ejects photons of light with the characteristic red-pink glow that illuminates this place with the color of a spring rose.

But in among this glow are dark forms, like flocculated clumps of matter held in a watery suspension. These are usually known as Bok globules, or in this specific case they are called Thackeray’s Globules after South African astronomer David Thackerary who spotted them in IC 2944 in the 1950′s.

They’re the densest remnants of the gas and dust-rich nebula that once was. Eroded by the punishing ultraviolet light of nearby young massive stars they are being eaten away, evaporating and shrinking. Although it’s possible that these clumps might one day condense under their own weight to form new stars, there are no signs of this happening. The more probable fate is for them to be dissipated back into component atoms and molecules, adding to the surrounding rosy fog.

It may sound a little mournful, but this is all part of a cosmic cycle, one day perhaps the contents of these globules will end up helping give birth to another set of stars, and it’s a fitting image to celebrate the great VLT.

Our high wilderness (Credit: T.A.Rector, I.P.Dell'Antonio/NOAO/AURA/NSF)

It’s only 240,000 miles away, yet this high wilderness still surprises and delights with clues about the origins of the solar system, Earth’s own water, and it even  supplies the occasional brilliant explosion.

If you’ve been paying attention recently you’ll have noticed that the Moon is getting a lot of press. One reason is that new investigations of the isotopic composition of volcanic lunar rocks, carbonaceous chondrite meteorites, and the Earth, are finding evidence that the mix of hydrogen and deuterium (‘heavy hydrogen’) is consistent between all three – indicating that they all share a common source of much of their water.

Until the past few years lunar science has tended to be of the mindset that the Moon is tremendously dry – not in the sense that it was missing great aquifers or subsurface lakes – but rather in the sense that the mineralogical content of the Moon included next to no traces of water embedded in it.

This has changed. The Moon is not awash in H2O, but it most certainly does contain water bound into minerals at levels ranging from parts per billion to several parts per million. It’s very interesting, but also a bit of a challenge to understand. In part this is because the current picture of how the Moon formed involves a giant impact some 4.6 billion years ago between proto-Earth and another embryonic planetary object. In this scenario the Moon is simply re-coalesced from the pieces of that impact, forming from the disk of debris around the Earth following the collision.

Splat, crunch, you name it, this was a violent event (Credit: NASA)

It’s possible that the energy of this collision might cause the loss of whatever water was around at that time – literally boiling it off to space and dissociating the molecules. This leads to a situation where Earth’s water was eventually ‘delivered’ hundreds of millions of years later on, by incoming material from further out in the solar system. But that mechanism could not have put water into the Moon’s deep interior because, once cooled, its rocky lithosphere acts like a thick sealant.

So, these new measurements of a common isotopic fingerprint between lunar water, terrestrial water, and the most primitive and ancient meteoritic rocks suggest a different picture. The Earth could have already had all of its water in place, and simply shared this with the Moon as both bodies emerged out of the orbital rubble – even with the extraordinary heat of collision and re-coagulation. It’s also possible that much of the interior of the Moon is relatively unscathed leftover from its embryonic progenitor, with a water signature intact.

The isotopes also indicate where all the water might have originated from – a vast population of water carrying carbonaceous chondrites. But what business did these primitive rocks have in the inner solar system more than 4.6 billion years ago? This is where it gets even more interesting.

A rather bold theory has emerged in the last couple of years that tries to sort out the evolution of the terrestrial and giant planets in these very early stages – well before 4 billion years ago, and 20-80 million years before the final assembly of the Earth.

It’s called the ‘Grand Tack’. It’s a little complicated, but in essence researchers asked how the giant planets, Jupiter in particular, might have behaved in the very, very young solar system. These large worlds should have formed before the smaller terrestrial worlds, siphoning up large amounts of primordial gas to make their great atmospheres. They find plausible arguments to suggest that Jupiter, interacting with the other giants and also with the mess of dust, rock, and remaining gas in the proto-planetary disk, could have migrated its orbit inwards to an astonishing 1.5 astronomical units – only 50% further from the Sun than the Earth is today.

Jupiter would then reverse course (‘tack’) and migrate back outwards due to gravitational interactions with Saturn. One consequence would be the destabilization of the orbits of a vast spread of cold, water rich, carbonaceous chondrites. These objects would have spanned from the distance of our present asteroid belt to far out in the young solar system – to where the giant planets are today. Some of these disturbed chunks would be cast inwards, intersecting and impacting with the still forming proto-Earth and providing it with its very specific isotopic flavor of water.

This is provocative stuff. If true it means our solar system actually has more in common with exoplanetary systems than we had perhaps thought – places where giant planets seemingly migrate their orbits with abandon.

It may not look very impressive, but that's a chunk of rock exploding as it impacts the Moon (NASA)

And today the Moon can still provide some real-time excitement when it meets up with bits of detritus from the early solar system. On March 17th an 88 pound rock slammed into the lunar surface and produced an explosive flash ten times brighter than any of the other 300 hundred lunar impacts recorded in the past 8 years (apart from the odd human-built spacecraft). It was caught in the act by an automated NASA telescope that’s been monitoring the lunar surface for just such moments.

Probably about a foot across and moving at some 56,000 miles per hour this meteoroid exploded with the energy of approximately 5 tons of TNT, not huge, but enough to pop like a flashbulb. In fact it was bright enough that anyone who happened to be gazing at the Moon for that instant could have seen it with their unaided eyes.

The event coincided with a spate of meteors seen in Earth’s northern skies, suggesting that we were also in the path of a cluster of material passing through the Earth-Moon system. It’s a great reminder, once again, that the processes of planet formation and evolution are ongoing, even if a bit gentler than 4.5 billion years ago!

This past week has seen the concentration of carbon dioxide (CO2) in Earth’s atmosphere reach a level of 400 parts-per-million, a value the planet hasn’t seen since several million years ago. To put this into some kind of context let’s take a look at the variation in CO2 over the past half century or so – via the classic ‘Keeling Curve‘.

Atmospheric CO2 concentration in parts per million as a function of time (Scripps/NOAA).

There are two basic features of this plot. First is that it wiggles up and down on an annual basis. That’s because the Earth has seasons and oceans and landmasses with living organisms that absorb and generate CO2. Plants, for example, tend to absorb CO2 in summers when they’re growing, and can release CO2 in winters when they’re rotting or dormant. The planet is also lopsided in the sense that there is more ‘habitable’ continental land mass  in the north than in the south – otherwise the net contribution to CO2 variation between northern summer and southern winter, or vice versa, would cancel out.

The second feature of this plot is that CO2 concentration is increasing with time. Why? Well, it’s simple, it’s because of us. This is seen most starkly if we take a look at a rather longer timeline – made using ice-core measurements of atmospheric CO2 (since our ancestors weren’t monitoring the atmosphere for us). It begins going uphill just around 1760 – the start of the Industrial Revolution.

CO2 concentration back to the 1700s - it starts rising around 1760 (Scripps)

You can begin to see just how steep the rate of change has become since the mid 20th century if we go even further back and look at the past 800,000 years.

See that little spike at the right hand side up to 400 ppm? That’s us, today. Although CO2 concentrations have been far from stable over the past 800,00 years, they take a sharp upward turn right in line with the rise of industrialized human civilization.

CO2 atmospheric concentrations from ice core sampling - for past 800,000 years (Scripps).

Now of course the ice core data are not perfect, there could potentially be some other spikes in there that get washed out in the measurements, but we would probably spot anything like our present fast rise.

How far back do we need to look to hit similar CO2 levels to today’s? It’s not quite clear, but it might be around 3 to 4 million years. A study by Bartoli, Honisch, and Zeebe in 2011 measured boron isotopes in the mineral shells formed by types of plankton, and suggests this was the case.

Looking further back, across more of the immense history of the planet, and we see that CO2 wanders all over the place. For example, here are some estimates showing both measurements and computer models (timeline flipped from previous plots).

500 million years of CO2 concentration on Earth (This figure was prepared by Robert A. Rohde from published data and is incorporated into the Global Warming Art project).

There’s a lot of uncertainty, but it’s clear that even our present 400 ppm CO2 concentration is small compared to what it has been tens to hundreds of millions of years in the past. Amounts that were five to twenty times higher than today seem more like the norm.

But humans, and the world we find around us, didn’t exist back then. These were periods where the Earth, our lovely home planet, would have felt about as alien as some of the exoplanets we’re now discovering in the surrounding universe. The environmental chemistry, the fauna (not always any flora), and the climate may have never before been a match for what it has been the past million years or so.

Like it or not, the historically low trough in the CO2 concentration of yesterday is a defining characteristic of the window of opportunity where our peculiar ape-related ancestors managed to get a foothold. The fascinating but rather terrifying thing is that we’ve now gone global, and we’ve learned how to extract vast amounts of energy from our environment, driven by an extraordinary ability to innovate and survive. By doing so we’ve altered that window, significantly changing the chemical composition of the atmosphere. And although I’m not going to discuss it in detail here, simple physics tells us what’s going to happen next. You cannot deny basic thermodynamics.

This is merely one change our presence has brought to the planet. There are many others. In fact you can now be a first-hand witness to the visible alterations going on around the globe through the magic of Google Earth. Terabytes of imaging data from 1984 to the present have been stitched together to allow a timelapse view of just about any part of the world. Go check it out here.

Even in this day and age of planetary awareness it’s pretty amazing to see just how infested a place it is. Here’s an example, Las Vegas, 1984 to 2012.

What happens in Vegas apparently spreads from Vegas....

Once you’re done with looking at other examples, try entering your own search…it’s quite educational.

Is it all doom and gloom? Yes and no. Clearly we’re testing the limits, we have a good chance of pushing our planet (if we haven’t done so already) to a place it hasn’t been to for millions of years – the kind of place that we might not like. The kind of place that might kill us. But we’re also amazingly clever, or else we wouldn’t know that we’re doing this. So what’s going to happen?

I wish I knew. But as a scientist, and an optimist, I can’t help but notice that if we’re serious about looking for life beyond the Earth and if we’re serious about looking for complex, technological life, it’s this kind of filthy disregard for planetary equilibrium that we should be sniffing for. We might have to wait a while if we find suitable candidate worlds to aim our telescopes at, but it’s conceivable we might catch some other life-form making precisely the same mistakes we are.

Through early morning fog I see
Visions of the things to be
The pains that are withheld for me
I realize and I can see

That suicide is painless
It brings on many changes
And I can take or leave it if I please

(Johnny Mandel and Michael Altman, ‘Suicide Is Painless’/M.A.S.H. theme)

Halley up close in 1986 (Giotto mission, ESA)

It happens every year around now, and this year should peak on May 5th at approximately 9pm EDT (in the wee hours of May 6th if you’re on GMT). Little pieces of material that once belonged to the nucleus of Halley’s Comet will zip into our atmosphere as meteors.

The Eta Aquarids (so-called because the meteors appear to radiate from a direction on Earth’s sky close to the star Eta Aquarii in the Aquarius constellation) come from a dusty trail of material that probably separated from the comet several hundred years ago. Although Halley’s – a ‘short period’ comet that passes through the inner solar system every 75 or so years – isn’t going to hit the Earth in the foreseeable future, some of its filth does quite regularly.

In fact the Eta Aquarids are not the only bit of Halley muck the Earth encounters, the Orionids are usually even more potent, arriving in our skies in late October every year. Just like the Aquarids, these particles – some very tiny, some a little bigger – trace out, or stream, along what has been Halley’s orbital path. This highly elliptical trajectory passes close to our own orbit around the sun in two places – and thus we see a May meteor shower and an October one, roughly six months apart.

Halley's position over recent times, and in the near future - where its orbit intersects Earth's is where the meteor showers are seen (Credit: Steve Dutch, U. Wisconsin)

It’s a wonderful reminder of the dynamic and complex solar system that we live in. Go take a look if you can!

NASA will also be running a live stream, so you can witness the meteors remotely.

The recent discovery of two potentially ‘habitable’, nearly Earth-sized, planets in a five-planet system around the very distant star Kepler-62 reinforces the fact that astronomers are edging closer and closer to finding worlds that have a chance of resembling our home world in some way. But there are so many unknowns that it’s tremendously difficult to state with any certainty what the surface environment might be on such planets, much less what the odds are for life and a functioning biosphere. Still, what these discoveries do provide us with is a set of new questions.

For example, if we ever manage to study a potentially terrestrial-equivalent planet with enough fidelity to measure its atmospheric properties (and there’s good reason to think we’ll do this within the next decade), we need to know what to look for. Chemical disequilibrium is one fingerprint of life on a planet, but so too is the way the planet responds to what are called ‘external forcings’. That’s stuff like seasons – the varying energy input as the planet orbits its star, and as it spins about its axis – slowly or quickly.

Which is one reason a newly published result by Jasechko et al. in Nature is particularly fascinating for astrobiologists (see also this). The study, titled ‘Terrestrial water fluxes dominated by transpiration‘, uses a wealth of data on the isotopic fractionation of oxygen and hydrogen in water on Earth’s continental masses, along with some careful mathematical modeling, to learn about the processes by which water goes from being a liquid to a vapor in our atmosphere.

Electron microscope image of a stomata on the underside of a plant leave - a 'mouth' that allows water vapor to escape to the air.

In a nutshell, when water evaporates physically – like in a drying puddle – the molecules that turn to vapor consist preferentially of lighter isotopes (atomic nuclei with lower neutron counts), leaving behind the heavier stuff for a while. But when a plant takes up water, carries it through its structures, and breathes it out as vapor through its stomata – in other words transpires water – it doesn’t seem to care whether the isotopes are light or heavy, and an equal mix goes into the atmosphere as is left behind as liquid.

So, in principle, this offers a way to keep track of how much water is put into our atmosphere by plant transpiration as opposed to simple evaporation. It’s far from simple though, because water of course rains back onto the surface. But land-locked lakes offer a way to sample how the isotopic flavors all end up mixing together – because we have some hope of modeling how they get supplied and where the water goes.

The upshot is that it seems likely that 80 to 90 percent of the water that undergoes ‘evapotranspiration’ (the combination of simple evaporation and plant transpiration) is carried by transpiration alone. That’s five to ten times more than via direct evaporation, and as much as four times more than previously thought. To put this in further perspective; it means that every year 62,000 cubic kilometers of water is moved by plant life from the continental surfaces of the planet into the atmosphere. That’s a lotta water, the same as a giant droplet some 50 kilometers in diameter.

But the most interesting thing from the point of view of observing how a planet functions, is the energy involved. This study estimates that roughly half of the solar power absorbed by the Earth’s continental surface goes into driving plant transpiration. That’s half of 70 Watts per square meter on the planet’s landmasses, which add up to about 5,000 Terawatts of power (5×10^15 Watts, annually averaged).

Thus, not only is a huge piece of the Earth’s hydrological machinery driven by life, it’s quite the power hog. Us filthy humans use energy at a rate of about 15 Terawatts, which is barely 0.016% of the average 89 Petawatts of solar power absorbed by all land and oceans. Transpiration could account for a much more substantial 5.6%.

If correct, this has some profound implications for the way in which climate models handle biologically driven water transport. It may also have something to tell us about the response of a life-rich world to varying stellar input, and what we might expect to detect in its atmosphere. Since transpiration is affected by a host of physical characteristics of both the plants themselves and the environment – from the number of leaves, to local temperatures and wind conditions – it’s tempting to imagine that one day we might be able to deduce some of these details on an exoplanet by simply monitoring the water vapor in its atmosphere.

Of course that assumes many things about the commonality of vascular plant life across the cosmos, which is a wee bit of a stretch since such forms didn’t arise on Earth until about 400 million years ago, but we can still speculate that mechanisms like transpiration could evolve elsewhere.

“Prediction is very difficult, especially if it’s about the future…”
Neils Bohr

Inside an O'Neill cylinder - life amongst the stars, circa 1970 (NASA)

Back in the 1970′s the physicist Gerard O’Neill and his students investigated concepts of vast orbital structures capable of sustaining entire human populations. It was the tail end of the Apollo era, and despite the looming specter of budget restrictions and terrestrial pessimism there was still a sense of what might be, what could be, and what was truly within reach.

A pair of space habitats on a giant scale (NASA)

The result was a series of blueprints for habitats that solved all manner of problems for space life, from artificial gravity (spin up giant cylinders), to atmospheres, and radiation (let the atmosphere shield you). They’re pretty amazing, and they’ve remained perhaps one of the most optimistic visions of a future where we expand beyond the Earth.

But there’s a lurking problem, and it comes down to basic physics. It is awfully hard to move stuff from the surface of our planet into orbit or beyond. O’Neill knew this, as does anyone else who’s thought of grand space schemes. The solution is to ‘live of the land’, extracting raw materials from either the Moon with its shallower gravity well, or by processing asteroids. To get to that point though we’d still have to loft an awful lot of stuff into space – the basic tools and infrastructure have to start somewhere.

And there’s the rub. To put it into perspective I took a look at the amount of ‘stuff’ we’ve managed to get off Earth in the past 50-60 years. It’s actually pretty hard to evaluate, lots of the mass we send up comes back down in short order – either as spent rocket stages or as short-lived low-altitude satellites. But we can still get a feel for it.

To start with, a lower limit on the mass hoisted to space is the present day artificial satellite population. Altogether there are in excess of about 3,000 satellites up there, plus vast amounts of small debris. Current estimates suggest this amounts to a total of around 6,000 metric tons. The biggest single structure is the International Space Station, currently coming in at about 450 metric tons (about 992,000 lb for reference).

This may look like a lot of stuff....but (NASA, Apollo 11 launch)

These numbers don’t reflect launch mass – the total of a rocket + payload + fuel. To put that into context, a fully loaded Saturn V was about 2,000 metric tons, but most of that was fuel.

When the Space Shuttle flew it amounted to about 115 metric tons (Shuttle + payload) making it into low-Earth orbit. Since there were 135 launches of the Shuttle that amounts to a total hoisted mass of about 15,000 metric tons over a 30 year period.

This begins to sound a bit better right? Hang on though. Take a look at one of these:

Your common or garden supertanker (Credit: US Navy)

This kind of tanker, fully loaded, is about 550,000 metric tons. That’s thirty-six times more mass than the Space Shuttle’s lifetime transfer to orbit. It’s one tanker. Could you build the basic infrastructure to mine and refine a trillion-ton raw asteroid, turn it into metals, materials, tools, and machines with this amount of building material? Perhaps, just. But O’Neill cylinders? A long way off.

By now you may be feeling depressed. Gravity really does suck. But I don’t think realism is a bad thing. In fact what this tells us is a simple, obvious fact. To reach that point of break-even, where what we’ve raised to space is surpassed by what we’ve made in space, we just need to get a little better at step 1. An oil tanker may be some 30 times more massive than 135 Shuttle flights, but that is not a bad factor to overcome. If it were a thousand, or a million, that would be the time to forget it.

So the efforts of space agencies and private launch operations like SpaceX, or Orbital Sciences to drastically reduce the cost of that first step are truly critical. I think there is still hope that an off-world future awaits our species – and it may be vital for our long-term survival.

[Before comments appear about how we shouldn't spend resources on such things until we've resolved our earthly problems: yes, sure, but NASA's entire budget (for example) is at present less than 0.5% of the entire US federal budget. At about $18 billion it is less than the wealth of some individuals on the planet. And other nations don't spend as much, the European Space Agency's budget is about $13 billion. For comparison the National Institutes of Health have a roughly $30 billion annual budget. And the science and technology of space has enabled us to study our home planet in ways that have become central to evaluating and improving the quality of life for all humans, from understanding weather and climate, to population growth and land-use. So there.]

Enter a crowdfunded effort to place ‘We Are The Explorers’ as a trailer to the upcoming Star Trek movie ‘Into Darkness’ on as many screens as possible. It’s been tremendously successful so far, and will air on 50 screens nationwide for the first 8 weeks of the movie’s opening – as an edited 30 second piece. The campaign is now working to hit a goal that’ll enable them to put the trailer in at least one theater in every state in the USA for two weeks.

Although the gravelly voiced narration (and yes, that is Optimus Prime) or discretely US-centric content might not be to your taste (but hey, this is NASA and US $’s foot the bill), it’s a very cool presentation. And yes, it’s pretty inspirational.

Here it is in full.

Recent debates over whether or not the Voyager 1 spacecraft has ‘left the solar system’ typically leave out some critical details. The limits of the Sun’s particle radiation is not the physical edge of the contents of the solar system, but it is the point of changeover to the exceedingly tenuous atmosphere of matter and magnetic fields that fills the space between the stars in our galaxy.

It’s been a hot topic recently because the Voyager 1 spacecraft, after 36 years of cruising away from us, now seems to be passing through a zone described as the ‘magnetic highway’, where the Sun’s magnetic field lines connect to those pervading interstellar space in our galaxy. This marks a transition where Voyager is going to move beyond the heliopause – where the endless flood of particle radiation streaming from our sun – stuff like electrons and protons – has become sufficiently diluted that it no longer pushes through the tenuous particle radiation and matter between the stars. This is the entry point to the interstellar medium, in a sense the atmosphere of the Milky Way.

But this has led so some misleading comments about ‘the end of our solar system’. NASA recently released a statement on March 20th, 2013 to try to clear up the confusion about Voyager’s whereabouts:

“The Voyager team is aware of reports today that NASA’s Voyager 1 has left the solar system,” said Edward Stone, Voyager project scientist based at the California Institute of Technology, Pasadena, Calif. “It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space. In December 2012, the Voyager science team reported that Voyager 1 is within a new region called ‘the magnetic highway’ where energetic particles changed dramatically. A change in the direction of the magnetic field is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed.”

However, I feel compelled to write this post because even NASA’s statement doesn’t quite manage to explain what’s different between ‘leaving the solar system’ or ‘reaching interstellar space’ – and there is a difference, for this solar system or any other.

Something like this is happening, Voyager 1 (upper spacecraft icon) is in a messy region close to the interface (NASA/JPL-Caltech)

Like any normal star, the Sun creates what is in effect a bubble of its own effluvia. It does this by exerting a pressure against the interstellar atmosphere, but the further away you get the weaker this pressure. Exactly where the solar pressure become equal to the surrounding pressure depends on a lot of factors. It depends on things like magnetic fields that interact with electrically charged matter, it also depends a great deal on exactly where we are in the galaxy and the local density of this interstellar atmosphere – which is always changing as we follow our lengthy galactic orbit, a journey of about 230 million years.

Regions of denser interstellar atmosphere, or medium, are expected to drastically shrink the size of the Sun’s bubble, bringing the heliopause in close. Variations in the Sun’s activity will also effect this. In other words, the heliopause is not some fixed ‘edge’ to our solar system, and it just happens to occur out beyond all the major planets at this time.

It is however the place at which the Sun’s extended atmosphere gives way to the atmosphere of the galaxy at large. So while one can say that beyond this is interstellar space, that’s a little confusing. It doesn’t mean that one is leaving the solar system, just that one is now bathed in a different medium – the interstellar medium, not the solar medium.

But if the heliopause, and Voyager 1′s present location just within it, is not the edge of the solar system, where does the solar system actually end?

It’s a good question. In my opinion the most physically sensible marker is the distance from the Sun at which the Sun’s gravity can no longer sustain objects in long-term stable orbits. In other words it’s the distance at which the gentle tug of other stars, and even the subtle variations in the net gravitational field of all the matter in the Milky Way, can perturb and destabilize the trajectory of any lonely, cold, bodies out there.

The problem is, much as with the heliopause, that this may not always be at the same distance from the Sun. Again, our movement around the galaxy and the hither-and-dither of other stars and objects result in a slowly shifting gravitational landscape. Nonetheless, rough estimation suggests that it’s about 1 light year away. Not coincidently this is also the speculated outer edge of the Oort cloud – a vast structure consisting of trillions of icy chunks of detritus flung outwards while our planets formed some 4.5 billion years ago.

A (somewhat old) artist's impression of the Oort cloud (Credit:NASA)

The Oort cloud is the likely origin of very long-period comets – objects that come falling inwards with orbits that may take anywhere from hundreds of years to millions of years to complete. For example, Comet West was last seen in 1976. If you want to see it again you’ll need to wait about 6 million years, since it’s now swinging back out to its far point of some 1.1 light years away.

All of which means that while poor old Voyager may have begun to taste a little fresh galactic breeze in its face, it’s still a very, very long way from passing beyond the wealth of islets that separate us from truly open interstellar space.

In fact, since one light year is about 63, 240 astronomical units (AU) from the Sun, and Voyager is currently about 124 AU from the Sun, moving away at approximately 3.6 AU a year, it will take another 17, 500 years (give or take) for it to move beyond the outer Oort cloud.

Reports of Voyager having left the solar system are therefore a little premature.

The greatest minds have tried to contemplate the vastness of nature

Grasping for an understanding of the true scale of the cosmos is a vital part of how we try to conceptualize reality and our place among it all.

But it’s tremendously difficult, whether we’re seeking that ‘oh wow’ moment, or trying to gain intuition that’ll help us solve the next scientific problem. So time and time again we look for ways to calibrate our senses, to reach for some kind of perspective.

Perhaps we do this by starting with a thought-experiment about something familiar and cozy.

‘Imagine this orange is the Sun’.

Next comes the Earth as a tiny seed, a hundred and nine times smaller, placed about 107 orange-diameters away – that’s roughly 320 inches or 9 yards away (I know because I looked up the average diameter of Valencia oranges, really, I did). In this case the outermost major planet, Neptune, is a small blackcurrant located 270 yards further away. The next star, Proxima Centauri, is represented by another orange (actually more like a grape, it’s a low mass star) roughly 1,400 miles away.

It’s quite effective, we’re lured into thinking about something ordinary, and the next thing we know we’re gawping at the colossal gulf between us and another sun. You know, one of those thousands of twinkly things you see in the night sky (with good eyesight, in the middle of dark nowhere). It’s almost cruel to point out that on this scale the other side of our single galaxy (less than a hundred billionth of the total population of galaxies in the observable universe) would only be reached after traveling about 25 million miles from our citrus mother.

The Sweden Solar System (centered in Stockholm, naturally)

This is one example. Sometimes our Sun is a basketball, or maybe it’s the dome of the local planetarium. In fact numerous physical models exist around the world that play this same trick, there’s even a list of them on (of course) Wikipedia. A particularly ambitious one is the Sweden Solar System model – stretching literally the length of the country. In this case the Sun (including the corona) is represented by the Ericsson Globe arena in Stockholm.

It’s impressive, and by the time you’ve slogged the nearly 600 miles from the Sun to the termination bow shock above the Arctic circle in northern Sweden, you’ll likely appreciate that this is merely a 1:20 million scale representation.

Ericsson Globe - representing the Sun

But it’s awfully hard to keep all of this in our minds, we’re just not used to experiencing such different levels of scale all at once, and a similar challenge exists if we want to go in the other direction, to the microscopic.

These days atoms perhaps don’t seem quite as tiny or remote as they once did – even though they typically span barely 0.1 nanometers (a ten-millionth of a centimeter). Ingenious devices like the tiny proboscis of an atomic force microscope can be used to map and even manipulate atoms, as well as sense their covalent bonds with other atoms – all on a run-of-the-mill lab bench.

But once we descend into these structures, the same incredible gulfs in scale separate out their constituents. It’s trickier because the physics is trickier, with particles exhibiting their quantum mechanical weirdness, and things get fuzzy. Crudely speaking though, if we scaled the size of something like a gold nucleus to the size of the Sun, the most probable location of the outermost electron of the gold atom would be twice as far away as Pluto’s average distance.

It means that similar ratios of space exist inside us to those around us. In fact it’s remarkable how much empty space pervades everything we find familiar, and it’s one of the reasons the universe can build obscenely dense objects like white dwarfs or neutron stars – there’s just a lot of spatial buffer that can be eliminated when you squeeze stuff together.

And of course it doesn’t actually stop here. Looking further inwards, it may be (with emphasis on the may), that at a Planck scale (of 10-to-the-power-of-minus-33 centimeters) the fundamental constituents of the universe are resonating strings of compacted, teeny-tiny, multiple dimensions.

Perhaps these are the ultimate granular pieces of nature, but in some ways they’re in the middle of nowhere. To try to convey this makes for some even more challenging ratios. For example, first consider that our observable universe stretches in all directions for about 435 billion trillion kilometers, which corresponds to about 4 to-the-power-of-28 centimeters. So the difference in size between the Planck scale and, let’s say, a small grape, is roughly equivalent to the difference between that grape and something a 100,000 times larger than the entire observable universe.

Ouch.

But this isn’t the full stretch, the full measure of all that there is. The observable universe is merely the universe from which light has had time to propagate to us, from our cosmic horizon. Beyond this? Well, good question. Some theoretical models for a multiverse suggest that there are an infinite number of other universe volumes scattered across these superhorizon scales, so that there are also an infinite number of other universes just like ours, as well as not quite like ours, or entirely unlike ours, and so on.

Of course it might not be that bad. Some of these models, involving what’s known as chaotic inflation, suggest that there may be merely 10-to-the-power-of-10-to-the-power-of-10-to-the-power-of-17 other universes. Actually it might not be quite so overwhelming because our paltry human senses would likely only be able to distinguish about 10-to-the-power-of-10-to-the-power-of–16 of these. Why so few you ask? Because the human brain can’t assimilate more than about 10-to-the-power-of-16 bits of information, we simply don’t have enough atoms in our noggins. I’m sure that makes you feel better.

For me, discussing nature’s scales is one of the most challenging, yet thrilling, tasks as a scientist. There is something so wonderful about nature’s blatant disregard for us in all of this – and yet here we are.

It’s so tremendously important to keep trying though, because perhaps we can get just a handful of those neurons in our brains to see something new. And whenever we see something new we have a chance of understanding ourselves a little bit more.

There is also something just absurdly funny about it all. And of course, as usual, Douglas Adams got there first:

“…. Bigger than the biggest thing ever and then some.
Much bigger than that in fact, really amazingly immense, a
totally stunning size, “wow, that’s big”, time. Infinity is just so
big that by comparison, bigness itself looks really titchy.
Gigantic multiplied by colossal multiplied by staggeringly
huge is the sort of concept we’re trying to get across here.”

(D. Adams, The Restaurant At The End Of The Universe)

Jupiter seen by Cassini (NASA)

New analysis of data taken by the Cassini mission during its encounter with Jupiter in 2000 reveal that exceptionally clear atmospheric ‘hotspots’ effectively ride up and down in the Jovian skies as they are formed by what’s known as a Rossby wave – a phenomenon familiar to us here on Earth.

The authors of the study have produced such an excellent video explaining all of this that it’s all you need to look at (really, it’s that good). The original scientific article is by Choi et al. in the journal Icarus, with a press release here.

The planets of HR 8799 (labeled). The starlight has been suppressed and mostly removed (Credit: Project 1640, Oppenheimer et al.)

Using cutting edge techniques, a team of astronomers has directly imaged a distant system of four planets, and made history by obtaining simultaneous spectra of these worlds.

This first comparative look reveals that the objects each have distinct atmospheric compositions, none of which directly match any previously known class of astrophysical body.

Only a tiny handful of exoplanetary systems exist where we have been able to spot planets directly. Detecting their emitted, or reflected, light is awfully tough when it’s millions to billions of times fainter than the radiation pouring off their parent suns.

One such system surrounds HR 8799 – a very young, variable, and moderately large star, weighing in at about 1.5 times the Sun’s mass, and located about 128 light years away. Back in late 2008 it was announced that 3 planets had been imaged using advanced adaptive optics at the great Keck and Gemini telescopes in Hawaii. A couple of years later and a fourth planet was spotted.

These are not the kinds of planets we’re used to. For one thing they are all hot – glowing still from their recent formation within the last 30 million years or so, with temperatures between about 800 and 1000 Kelvin (980F to 1300F). They are gas giants, but they weigh in at anywhere between about 5 or 7 times the mass of Jupiter to as much as 20-30 times. In fact, there has been some debate about whether they really are planets or more massive objects known as brown dwarfs.

Using older data from the Hubble Telescope the orbital periods have been estimated (NASA/Space Telescope)

This system also seems pretty alien if we look at where these planets orbit. Labeled b, c, d, and e in order of discovery, their present distances from HR 8799 are about 68 AU, 38 AU, 24 AU, and 15 AU – where an AU is the distance of the Earth from the Sun.

This means that the closest planet to the star, ‘e’, orbits about midway between where Saturn and Uranus orbit in our solar system, planet ‘b’ would be out where our Kuiper belt ends. It’s a radically different architecture than what we’re used to.

Getting a handle on the composition and atmospheric structure of these mysterious gassy worlds would be a tremendous advance. A spectrum of the light from such hot worlds would provide just such a fingerprint. But efforts to measure this have had limited success, until now.

Enter Project 1640, a multi-year effort using the 200-inch wide Palomar telescope in California. It applies state-of-the-art adaptive optics to minimize the blurring effects of Earth’s atmosphere, a sophisticated coronagraph to block HR 8799′s light in order to reveal the planets, and a spectrograph that turns the pixels of each image into 37, 146 spectra.

The Project 1640 instrument (left) about to be installed at the 200-inch Palomar (right) (Credit: Project 1640/AMNH)

If that sounds technical, well it is. The upshot is that not only can the planets be seen in a system like HR 8799, but, with some skill, a spectrum can be obtained for each simultaneously – a direct probe of their actual composition and nature.

The results of this exploration are reported In a new paper by Ben Oppenheimer and colleagues, to appear in The Astrophysical Journal. It’s pretty jaw-dropping. Although the four planets are glowing similarly bright, they are each quite different from their siblings.

There are signatures of compounds like methane and ammonia, but also of things that might be acetylene and hydrogen cyanide – it’s a real mix. To quote Oppenheimer et al. – their analyses suggest that the planets are like this:

You might be glazing over with this, so what does it mean? First, it means that these objects look more like planets than they do brown dwarfs. They’re also clearly, and remarkably, distinct from each other – despite (presumably) all being big, hot, gas giants. The only one that looks vaguely familiar is ‘e’ – whose spectrum is a bit like that of the night-side of Saturn.

Exactly how and why these worlds are so varied is a juicy puzzle. The researchers suggest that it might in part be a result of ultra-violet light flooding the system in bursts from the youthful star HR 8799. A thousand times brighter than the equivalent from our Sun, this radiation can drive all sorts of chemical and physical changes in planetary atmospheres.

In fact there is tentative evidence for the planetary spectra changing over a period of just a couple of months. This could be the effect of the changing stellar radiation. It could also perhaps be that most familiar of planetary properties, the phenomenon we call weather.

This is a gorgeous piece of astronomy, and it represents a new era of discovery, one where the diversity of other worlds is going to keep us very, very busy.

Not bad for a spot of early reconnaissance.

[Note: Full disclosure - it's only fair to say that I have been familiar with Project 1640 since its inception, and count several of the authors as good colleagues, so I am naturally biased in my excitement]

Deep in the Antarctic (Credit: NSF)

Recent efforts to extract a water sample from the ancient sub-surface Antarctic Lake Vostok seem to be yielding some promising results. Russian scientists now claim detection of previously ‘unclassified’ microbial organisms.

On January 10th this year Russian scientists reported that they had extracted an ice core from over 3,600 meters depth – containing what was expected to be water forced up under pressure into the borehole from Vostok before freezing solid.

It could be the first time this water has seen sunlight in millions of years, and perhaps tens of thousands of years since it mingled with anything other than the rest of the lake. At the top of the scientific to-do list was to find out if anything lives in Vostok, leading an existence as isolated as its water.

A little over two weeks later a US funded team drilled into Lake Whillans – a shallower, far less extensive body of water under the West Antarctic Ice Sheet. In short order the US team announced that they were finding microbial life, bacteria, in their samples of water and sediment. It seemed that the hunt was warming up for what could be some of the most extreme organisms anywhere.

Vostok is perhaps the greater prize though, and eyes have been on Russia waiting for word on whether anything has indeed come up from the pitch black depths of the coldest place on Earth.

Now, through Russian state media, it has been announced that preliminary examinations of the water indeed reveals signs of life. Not just any life though, the message is that this is microbial life of an ‘unclassified’ nature. To quote the Russian news agency RIA Novosti:

“After excluding all known contaminants…we discovered bacterial DNA that does not match any known species listed in global databanks. We call it unidentified and ‘unclassified’ life,” (Sergei) Bulat said.

It’s being reported that seven samples from the extract ice core show signs of this bacterial DNA. While the technical details are not yet available it seems that when the scientists (including Sergei Bulat of the Laboratory of Eukaryote Genetics at the St. Petersburg Nuclear Physics Institute.) compared this DNA to a database of known species they found no clear match. The closest they could come was about 86% similarity, which is far enough off to suggest a new species.

Obviously we’ll need to wait to see the details. Phrases like ‘bacterial DNA’ are pretty vague – are they looking at things like the ubiquitous 16s rRNA, or some other sequence selections typically used for metagenomic analysis? Do they have cells under a microscope?

It looks to be exciting news though. Decades of hard work to reach one of the most alien places on Earth may actually be revealing lifeforms we have not knowingly encountered before. It doesn’t really get better than this!

I will update this post as more information comes in.

The bottom of the world (Reuters)

Europa: as the human eye might see it (colors adjusted, Credit: NASA/JPL/Ted Stryk)

Jupiter’s enigmatic moon Europa has long been thought to contain a huge ocean beneath its icy crust, but what is in that ocean and does it ever come to the surface?

Since the Voyager and Galileo probes explored the Jovian system, its moons have presented an extraordinary and fascinating puzzle. The largest of the 67 known moons are the ones that Galileo Galilei watched wend their way around Jupiter’s bulk back in the early 1600′s – Io, Europa, Ganymede, and Callisto. These bodies are remarkable both for their size (Ganymede is 8% larger in diameter than the planet Mercury, Callisto is 99% Mercury’s size) and their diversity.

Io, orbiting closest to Jupiter out of these four Galilean moons, is the only body in the solar system other than the Earth with observable volcanism (as opposed to cryovolcanism). In fact it’s thoroughly covered in pimples, with an estimated 400 active volcanic structures. Tidal flexing due to Io’s elliptical orbit within Jupiter’s enormous gravitational field keeps it hot.

The Galilean Moons - and their incredible variety (NASA)

Ganymede and Callisto are covered in filthy water ice, each conceivably containing deep liquid water oceans a hundred or more miles beneath their surfaces. Although Callisto is far less differentiated than Ganymede, with its internal layers less well defined, suggestive of a colder history where material has still not settled fully in the moon’s own gravity well.

But Europa is perhaps the biggest mystery. Spacecraft imagery reveals a relatively smooth surface, criss-crossed by remarkable structures – cracks, plates, and signs of vast ice-floes that appear as if they once broke free and rolled into new positions. Some ‘chaos terrain’ suggests material atop of a much warmer, liquid water, body. Relatively few craters pock Europa’s surface, also indicating that it’s young and frequently replenished.

Measurements of magnetic fields, induced by passage through Jupiter’s own powerful field, point to a conductive medium somewhere beneath Europa’s frozen surface. Chemically rich water, in liquid form, is the best candidate. Perhaps an ocean descending to 60 or so miles, enough fluid to fill Earth’s seas twice over and capped with thick ice.

This ocean may be maintained by a combination of the same kind of tidal flexure torturing Io, along with a base of warm rock – something that might conceivably parallel the deep ocean hydrothermal systems we find here on Earth.

One hypothesis for the interior of Europa (NASA)

An ocean in Europa has provided ample room for speculation about the existence of life there. Many of the conditions seem suitable; liquid water and chemical feedstuff from a rocky interior could be sufficient to sustain organisms. We also know that much of life on Earth doesn’t require access to our planet’s surface – at least not directly.

One of the biggest stumbling blocks for figuring out whether Europa could sustain a sub-surface biopshere is the need for geochemical recycling, and particularly a source of oxygen to help drive its chemical engines. The surface of the moon, exposed to the harsh radiation environment around Jupiter, could be an excellent resource – but not if it’s sealed off from the interior.

Now a beautiful new piece of Earth-bound astronomical research seems to shed light on both the surface, and perhaps sub-surface, of Europa. Mike Brown and Kevin Hand have used the Keck observatory to produce a very fine spectral map of the surface of this moon – they do a 40 times better job at resolving the frequencies of light than the Galileo spacecraft managed up close.

What they have discovered, in a nutshell, is that a previously unseen ‘salt’ – magnesium sulfate, litters some of Europa’s surface. But this magnesium compound is only on the ‘trailing’ face of the moon – the side that receives the worst dose of particle radiation from the potent nest of magnetic fields and plasma circulating in the Jovian system.

The suggestion is that this form of magnesium salt is produced as radiation pummels Europa’s trailing side and catalyzes a reaction between preexisting sulfate formed on the surface (with sulfur originating from volcanic Io) and something containing magnesium. But we don’t think that the magnesium is just floating around in space – so it must be coming from Europa itself.

The authors point out that sodium and potassium are also known to exist on Europa’s crust, so now we can add magnesium to the mix. It’s less easily ‘sputtered’ off the trailing face of the moon by radiation, while sodium sulfates and potassium sulfates tend to be removed, so the magnesium component gets enhanced.

But if magnesium wasn’t always in the form of magnesium sulfate (seemingly produced only on the radiation heavy side of the moon), what was it? The best hypothesis is that it, together with sodium and potassium, was combined with chlorine – and it gets to the surface from the deep ocean.

In other words, this is indirect evidence that Europa’s ocean is full of sodium chloride, potassium chloride, and magnesium dichloride. If those sound kind of familiar, well they should. As Mike Brown notes in an excellent series of explanatory posts, if you go and lick Europa it’ll probably taste like a mouthful of Earth’s oceans.

This is also not entirely unprecedented. Recent measurements of the water geysers from Saturn’s moon Enceladus also suggest the presence of sodium and potassium salts (although whether chlorine salts or sulfate salts is not known).

The next steps will be to look for the presence of chlorine – which is tricky when they’re in solids, less so when they evaporate into space. Long term this all adds to a body of evidence that not only does Europa indeed have an interior liquid ocean, but that ocean somehow gets onto the surface, bringing salts and perhaps whatever else is down there.

This would also offer a chance for surface material to get back into the ocean, carrying chemical energy. It’s possible therefore that we’re beginning to see the intimate workings of a truly alien world, one that might yield even more surprises in the years to come.

Who's the fastest of them all? (Credit: NASA)

Of all the spacecraft humans have launched, there have been some impressively fast movers. But which holds the record?

It’s not an entirely idle question. Apart from the wow factor, it’s an interesting yardstick for gauging our capacity to explore the cosmos, from familiar planets to the icy depths of space.

However, as I quickly discovered in writing this post, it’s not always an easy quantity to evaluate. For one thing, launch velocities differ from eventual cruise velocities. And fancy interplanetary maneuvers like the ‘gravity assist‘ can provide temporary speed boosts that have to be taken into account.

It also depends on what you measure velocity relative to. Far away from the Earth it makes more sense to work with heliocentric (sun-relative) measurements. And (as you’ll see) you need not be zooming away into the void at all to reach the highest sustained speeds.

We can start off easy though. Launch velocity is something very definite, tuned to the finest level possible in order to insert a mission into its optimal trajectory. The record holder is also easy to find, it’s the New Horizons mission to Pluto and the Kuiper belt.

Launched by NASA in 2006, it shot directly to a solar system escape velocity. This consisted of an Earth-relative launch of 16.26 kilometers a second (that’s about 36,000 miles per hour), plus a velocity component from Earth’s orbital motion (which is 30 km/s tangential to the orbital path). Altogether this set New Horizons barreling off into the solar system with an impressive heliocentric speed of almost 45 km/s or 100,000 miles per hour.

The Sun’s pull is relentless though, so sometimes you need a helping hand. In 2007 New Horizons had slowed to about 19 km/s and made a flyby of Jupiter to snag a gravity assist (where the spacecraft ‘stole’ a tiny bit of Jupiter’s momentum) in order to regain about 4 km/s – before settling in for the long coast outwards. In the first figure shown here you can see how this is going to play out – heliocentric velocity is going to slowly drop during the journey through the Sun’s ever weakening gravity field. However, when it encounters Pluto, the spacecraft will still whizz by at about 14 km/s relative velocity.

New Horizons' heliocentric velocity during its mission (taken from the JHU mission design document by Guo & Farquhar)

This velocity profile is pretty typical, although quite simple. For comparison I’ve included a similar plot for Voyager 2′s trajectory (and it’s worth noting that Voyager 1 presently holds the record for highest velocity the furthest from the Sun, currently clocking a healthy 17 km/s or 38,000 mph).

Voyager 2's heliocentric velocity versus distance from the Sun - plus (in blue) the solar system escape velocity at each location. (Credit: Cmglee, Wikipedia)

The numerous gravity assists and course alterations in Voyager 2′s ‘Grand Tour’ of the solar system are writ large in its velocity history. Both Voyagers were able to build their escape route from the solar system while also taking in the sights – an incredible accomplishment.

But what about the other record holders? In terms of pure heliocentric velocity, the current champions are two probes called Helios I and II that were launched in 1974 and 1976. They entered orbits that took them closer to the Sun than the planet Mercury.

The nearer you orbit to a huge mass like the Sun the faster you have to move, and the Helios sisters moved very fast indeed. Both hit orbital velocities in excess of 70 km/s – or about 150,000 miles per hour.

But they’re not going to hold onto pole position for much longer.

Juno - solar panels extended (NASA/JHU)

First, NASA’s Juno mission to Jupiter will be arriving in the Jovian system in 2016 and will enter a polar orbit around the gas giant. But Jupiter weighs in at 317 times the mass of the Earth. Falling deep into its gravity well will accelerate Juno to a velocity of about 160,000 miles per hour relative to the planet, before it can swing by, drop speed, and get into its mission orbit.

In 2018 though, a new NASA mission – Solar Probe Plus – will be launched. Designed to come as close as 8.5 solar radii to the Sun (that’s about about 5.9 million kilometers or 3.7 million miles), it will hit orbital velocities as high as 200 kilometers a second (450,000 miles an hour).

To just put that incredible figure into perspective – going this fast would get you from the Earth to the Moon in about 1/2 an hour. It is also about 0.067% the speed of light.

It turns out that the fastest spacecraft do indeed go to the stars, in this case our nearest one.

[Movie from JHU's Applied Physics Laboratory]

Still image of fireball video (RT/Youtube/Potapow)

[Updated:] About 7,000 metric tons of meteor streaked across central Russia on Friday 15th February 2013, its fireball leaving great contrails in the sky and generating explosive shockwaves that smashed windows and damaged buildings. Reports indicate a number of craters a few meters across as the debris impacted the ground.

The Earth is constantly encountering chunks of solid material in the solar system. Typically the relative velocity of these encounters is between about 17 kilometers a second and 50 kilometers a second – in other words fast. Our atmosphere provides a roughly 60 mile barrier to these speedy pieces, and frictional and pressure forces generate high temperatures as material passes through it – probably reaching up to about 3,000 F (1,600 C), hot enough to melt and boil even rocky material.

We’re seeing this all the time. The streaks of pretty meteors (they’re not meteorites until they hit the ground) are usually very high altitude events and caused by tiny crumbs of matter. This stuff is part of the detritus of the solar system, the same material that once formed planets. It has a wide range of compositions. Some is iron-nickel rich, the exhumed pieces of what was once a planetary embryo some 4.5 billion years ago. Other pieces are even more primitive, the clumped splatters of minerals that have never formed part of anything bigger – unprocessed and primordial.

It all comes in every size imaginable, from microscopic grains to great big asteroids and cometary nuclei that may be miles across. But the bigger they are, the rarer they are and the less and less likely it is for their orbits to ever intersect with ours. It does happen though, and across Earth’s history we’ve been hit by some pretty serious stuff – ask the dinosaurs….oh wait, you can’t.

The trail of the meteor across the sky (Youtube/Gregor Grimm)

The event in the Chelyabinsk region of Russia is a spectacular example of what was probably a chunk of material just 15 meters across, perhaps weighing in at about 7,000 metric tons. Russian sources estimate that it had an initial velocity of about 30 kilometers a second and a low trajectory that carried it across a very significant area. It seems to have exploded into fragments at a few kilometers altitude and impacted the ground in a number of locations.

To quote the Russian English-language news channel RT: “Army units found three meteorite debris impact sites, two of which are in an area near Chebarkul Lake, west of Chelyabinsk. The third site was found some 80 kilometers further to the northwest, near the town of Zlatoust. One of the fragments that struck near Chebarkul left a crater six meters in diameter.” They also report that many hundreds of people have suffered injuries – presumably mainly from flying glass or debris due to the shockwaves.

The flash was reported in a huge area from the Chelyabinsk, Tyumen and Sverdlovsk regions, to Russia’s Republic of Bashkiria and in northern Kazakhstan.

My very crude estimate of the energy of the material pegs it at a couple hundred kilotons TNT equivalent before it hit the atmosphere. This could produce an airburst explosion of 70 kT, possibly more. [Update: this meteor likely produced about 100 times less explosive energy compared to what the fly-by asteroid 2012 DA14 - see below - would have caused if it impacted Earth - a few tens of kT versus about 3 mega-tons].

What's claimed to be a collapsed roof/wall of a local zinc factory - due to the meteor shockwave/explosion (Photo from Twitter.com user @TimurKhorev)

Image from Meteosat 10 of object soon after it entered the atmosphere above central Russia (Copyright 2013 © EUMETSAT)

What’s interesting, although almost certainly coincidental, is that a known asteroid – the object 2012 DA14 – is passing close to the Earth right now. It’s been the subject of a certain amount of media attention because it’s one of the closer passages of an object (about 46 meters across) at about 27,700 kilometers (17,000 miles) that we’ve been aware of.

However, 2012 DA14 is approaching Earth from the terrestrial south, while the Russian event was due to an object coming in from the north – so it’s highly unlikely that there is a physical relationship between these two things. In fact it just highlights the fact that this kind of meteor event is happening more often than we perhaps usually know. Seventy percent of the Earth’s surface is water and effectively uninhabited – there are likely plenty of meteors that are simply not witnessed or reported by anyone.

Pluto's currently known moons (Credit: NASA/HST)

Far from the Sun planetary bodies can hold onto many more moons. The latest count for Pluto is five satellites, and the most recent two need names.

Back in 2011 and 2012 it was announced that Hubble Space Telescope observations of the Pluto system had spied first one and then another new candidate moon. For a long time the only known satellite of this distant dwarf planet was the object Charon. With about 12% of Pluto’s mass Charon orbits once every 6 days and 9 hours – close enough to cause the center-of-mass of the system to actually lie outside Pluto’s surface.

But in 2005 astronomers spotted additional satellites, Nix and Hydra. These were inferred to have masses barely 0.03% that of Pluto, mere crumbs about 40 to 60 kilometers across orbiting some 2-3 times further out than Charon. And now we know that there are at least two more moons, currently designated as P4 and P5.

It’s a fascinating example of how the long-term stability of planetary satellites improves with distance from a star. Even though Pluto is a mere 0.00218 times the mass of the Earth, out at this distance from the Sun the gravitational tides that make it hard for inner planets to keep moons are so small that satellites can abound.

It’s not all good news though. P5 was detected because observations were made to help plan for NASA’s New Horizons spacecraft flythrough of the Pluto system in 2015. Going at some 30,000 miles an hour, New Horizons is exceptionally vulnerable to damage from even the tiniest chunks of material. Finding P4 and P5 adds evidence to suggest that Pluto may be surrounded by lots of tiny pieces of stuff – perhaps remnants from a collision between Pluto and a Kuiper belt object that helped form the larger moons.

New Horizons is already so far from Earth that signals take about 4 hours to reach it, so real-time piloting through the Pluto system is not an option. Luckily it may be that just a simple course correction is needed to pass a little further from Pluto than originally planned to minimize the risk of collision.

Regardless of that, tradition has it that the moons P4 and P5 need ‘proper’ names. There’s a mandate from the International Astronomical Union (IAU) that these follow the naming of the rest of the Pluto system – drawing on Greek or Roman mythology about the Underworld. However if good enough alternatives are thought up it’s possible the IAU would be tempted.

And here’s where YOU can play a role. The SETI Institute has just launched a ‘Pluto Rocks’ website where anyone can pitch in to vote for both their favorite classical name choices for P4 and P5, and write-in for something original.

So why not take a little time to help name some of the latest moons in our solar system!

It may not look like much now, but ISON has the potential to become a Great Comet (Credit: NASA/JPL-Caltech/UMD (Tony Farnham))

NASA’s Deep Impact probe has captured images of Comet C/2012 S1 (ISON), as it moves past the orbital distance of Jupiter on what may be its first trip inwards to the Sun, and possibly a spectacular show.

Comets are notoriously fickle beasts. Chunks of primordial rock, dust, and volatile ices that formed some 4.5 billion years ago around our fledgling sun, they can occasionally fly on Icarus-like orbits that bring them to the inner solar system.

Increasing solar irradiation warms their surfaces and sublimates components like solid water and carbon dioxide – creating great tails of reflecting gas and glowing ions, along with streams of dusty carbon compounds and silicates.

Up close: the nucleus of comet Hartley 2 - also imaged by the Deep Impact/EPOXI mother craft in 2010. Spouts of volatiles are erupting from the surface (Credit: NASA/JPL-Caltech/UMD)

Some of these bodies are on long elliptical orbits that bring them back again and again to the inner solar sanctum. Halley’s comet for example has an approximately 75 year long orbit, and its glowing passage has been recorded by humans some 29 times and probably seen many more.

Others fall inwards from a still mysterious region beyond all known major and minor planets – the Oort cloud. This detritus from our solar system’s youth exists somewhere between about 2,000 and 50,000 times further from the Sun than the Earth is, perhaps even stretching to a light year from us.

It’s these long-period comets (each of which may or may not ever visit us again) that have the greatest potential to light up the brightest as they fall inwards, since they may be essentially pristine, their volatiles ripe for a spot of solar heating.

Comet C/2012 s1, or ISON  (International Scientific Optical Network) was discovered in September 2012 by Russian astronomers Vitali Nevski and Artyom Novichonok. It’s an extremely promising candidate for becoming a truly spectacular object both before and after its closest solar approach of 800,000 miles on November 28th 2013.

Comet 17P/Holmes in 2007 - a blue tail of ionized gas to the right (Credit: Ivan Eder)

Of course we’ve all heard this before. Over the years many newly spotted cometary bodies have been touted as ‘the next great comet,’ only to sputter and fizzle to something less than impressive. The problem is that the precise composition and physical structure of any cometary chunk is hard to predict, as is its reaction to increasing temperatures. No two cometary bodies are the same.

But we keep hoping, because a bright comet is something amazing, and over centuries and millennia there have been some truly great ones. Last century, in 1910, the “Great January Comet of 1910″ (C/1910 A1) was visible during the day and lasted a couple of months. The Great Comet of 1882 became bright enough in September of that year (around its closest approach to the Sun) to be visible in the sky adjacent to the Sun. And there have been many more witnessed across human history.

Comet ISON is looking promising. On January 17th NASA’s Deep Impact spacecraft (the surviving mother craft of the Deep Impact mission to collide a copper impact probe with comet 9P/Tempel – which it did successfully in 2005) was able to snap a series of images of ISON from a distance of about 493 million miles, as the cometary body approaches about 4.8 Earth orbital radii (astronomical units) from the Sun.

Here is a timelapse movie of these pictures, if you look carefully you’ll see that already there are signs of a glowing tail some 40,000 miles long. It’s possible that ISON will not disappoint.

The postulated Oort cloud (Credit:ESO)

All comets present a smorgasbord of scientific data. Their tails of particles and dust providing insights to the streaming solar wind and interplanetary magnetic fields, and their contents providing insight to the rich chemistry of our proto-planetary system more than 4 billion years ago.

Oort cloud objects are also intriguing because they may represent material stolen from our stellar siblings. A long-standing problem has been that the number of long-period comets seems rather high compared to our expectations for the population density of an Oort cloud formed from icy material flung outwards during planet formation.

In fact the numbers are amazingly discrepant. While most models of solar system formation suggest there could be some 6 billion icy chunks in the Oort cloud, the comet counts indicate a population of about 400 billion. Quite a conundrum.

In 2010 Hal Levison and colleagues used computer simulations to demonstrate that this apparent over-richness of cometary bodies could be explained if our Sun had emerged from its stellar birth cluster with more than its fair share of these outer pieces. In other words, dynamical pulling and shoving with its sister suns resulted in the acquisition of a vast number of alien cometary bodies.

So not only might ISON be a bright and beautiful creature as it approaches the Sun, it could be truly a visitor from the stars.

Andromeda (GALEX/NASA/JPL)

There is something beautiful yet ominous about our nearest large galactic neighbor.

The Andromeda galaxy is a trillion star behemoth that spans some six times the diameter of the full Moon when seen through a telescope. At only 2.5 million light years away from the Milky Way it’s barely an intergalactic stone’s throw from us, and the gravitational might of our two galaxies is pulling them together against the stretching expansion of the cosmos. Every year we get closer by about 2 billion miles. And, as I’ve written about before, in some 4 billion years or so we’ll begin a process of merger, a grand slow-motion galactic collision.

The outcome of this will most likely be a new system, our merged components perhaps dissolving into a giant elliptical galaxy, with stellar orbits thrown into a vast puff. No more Milky Way, no more Andromeda, just distant memories.

These observations were made by Herschel's spectral and photometric imaging receiver (SPIRE) instrument. The data were processed as part of a project to improve methods for assembling mosaics from SPIRE observations. Light with a wavelength of 250 microns is rendered as blue, 350-micron is green, and 500-micron light is red. Color saturation has been enhanced to bring out the small differences at these wavelengths. (ESA/NASA)

But until then we get to observe this beautiful spiral object. Andromeda seems to be producing stars at a slightly slower rate than the Milky Way, but this doesn’t mean it’s devoid of stellar birth. New images from the ESA/NASA space observatory Herschel allow us to map out the cooler interstellar dust and dense regions of star and planet formation by sensing far infrared and submillimeter wavelength radiation from this matter. At these wavebands photons are less attenuated by gas and dust and less confused with starlight, allowing astronomers to peer deep into Andromeda’s nurseries.

Andromeda - to the left in far infrared, to the right in visible light (ESA/Herschel/PACS & SPIRE Consortium, O. Krause, HSC, H. Linz)

They’re extraordinary images, and here I show a comparison with the visible light image of Andromeda. Stars are being born in rings, spokes, and spiral arm structures throughout our neighbor. Chances are that we look a lot like this for any hypothetical Andromedan astronomer peering back at us across the void.

The 'John Klein' rock surface, target for drilling. Scale of image is approximately 1 meter across. Image has been white-balanced to mimic Earth-illumination (NASA/JPL-Caltech/MSSS)

NASA’s Curiosity rover is preparing to drill for the first time, into what appears to be sedimentary rock criss-crossed by mineral-filled veins.

Back in September last year the Mars Science Laboratory carried by the rover found a rocky outcrop on the wall of Gale Crater that was full of a crusty mix of cemented pebbles. It matched signs of an alluvial-fan feature seen from orbit and was some of the very best evidence so far of significant historical water flow across the martian surface.

Light color mineral veins in martian rock - a strong clue to a water soaked past (NASA/JPL)

Now Curiosity has entered Yellowknife Bay, a terrain that exhibits all the signs of a different type of water presence. In fact this depression in the landscape seems to be entirely distinct from the earlier Gale Crater landing site about 500 meters away.

Here sedimentary rocks (formed from the crushed remains of earlier rocks) are filled with fractures and veins of what might be hydrated calcium sulfate (bassinite or gypsum) – deposited when water soaked this area. There are also nodules of deposited material, cross-bedded layering, and even a rather shiny pebble embedded in sandstone that’s provoked our human pattern recognition system into thinking there’s a martian ‘flower’ popping from the ground.

It’s the perfect place for a spot of prospecting.

Over the next few days to weeks Curiosity will try out its drill, attached to the end of its 7-foot robotic arm. The drill has a bore depth of about 5 cm, enough to get well past the weathered crust of these rocks and to retrieve the grindings of an ancient martian environment.

The drill with 'bit' attached. Cylindrical sheath channels material up for collection. (NASA/JPL)

It’s not an easy task. There are concerns that a Teflon coating on the drill bit may flake off – contaminating any samples. So the first task will be to sacrifice a small amount of the upper layers of rock as an abrasive ‘cleaning’ material for the drill – getting rid of any Earthly contaminants before going deeper.

Once it does we’ll have a new window onto Mars’ deep past.

'John Klein' site in raw color (NASA/JPL-Caltech/MSSS)

Cross-sectional map of Lake Vostok situation (before drilling was complete) (Credt: National Science Foundation)

Break out the vodka. The first confirmed sample of water from the subsurface Lake Vostok in Antarctica has been retrieved.

Almost a year ago, in February 2012 Russian scientists and engineers drilled to a depth of nearly 4,000 meters in the ice above Lake Vostok – a 1,300 cubic mile volume of liquid water thought to have formed some 20 million years ago and to have been effectively isolated from the outside world for at least 100,000 years and possibly for millions of years. This was the culmination of a 23 year effort to reach the lake.

As I wrote in a previous piece back in 2012, Vostok presents an intriguing case for the study of both extreme organisms and evolutionary isolation, as well as an environment that parallels some of those that we think might exist elsewhere in the solar system – either in the subsurface of Mars, or on icy moons like Enceladus or even Europa.

Now it seems that perseverance may have paid off. By withdrawing the drill last year the scientists were able to allow the high pressure water in the lake to expand up into the borehole where it then froze. A strategy designed to minimize the chances of contaminating the lake from above.

Because that was at the end of the summer season last year, and the return of the brutal Antarctic winter, they had to wait until now to return and extract this core sample. Although previously retrieved samples may have come directly from the lake, this will be the first one that they know for sure originated in the liquid part of this immense underground structure.

Russian state-owned news agency Ria Novosti quotes the Arctic and Antarctic Research Institute, part of the Federal Service for Hydrometeorology and Environmental Monitoring:

“The first core of transparent lake ice, 2 meters long, was obtained on January 10 [2013] at a depth of 3,406 meters. Inside it was a vertical channel filled with white bubble-rich ice,”

What’s expected to follow is an intense study of the physical and chemical qualities of the water ice and an investigation into whether there are signs of microbial life. It will be fascinating to see what they find.

This ended the year long mission of NASA’s Gravity Recovery and Interior Laboratory (GRAIL). The twin spacecraft spent most of this time orbiting the Moon’s surface at a scarily low altitude of about 31 miles, sweeping in tandem above the dusty terrain never more than 140 miles apart from each other.

Gravity map of the Moon (Credit: NASA/JPL-Caltech/MIT/GSFC)

Microwave telemetry between the spacecraft, the Earth, and the application of basic geometry let GRAIL monitor the distance between Ebb and Flow to a precision of about a tenth of a micron – half the width of a human hair.

As with any planet or satellite the Moon’s gravitational field is not perfectly symmetrical. Variations in the density and height of material produce tiny variations in the gravitational acceleration felt by other objects. By sensing Ebb and Flow’s varying movement in orbit a detailed map of the lunar gravity field was constructed. With a knowledge of the topographic features on the surface this can be turned into the equivalent of a medical tomographic reconstruction of the lunar interior – and it’s lumps and bumps.

The data is amazing, but GRAIL had one last gift to give. In the days leading up to their crash on the lunar surface the spacecraft returned imagery from their ever lowering orbits.

This is the quite surreal and beautiful timelapse footage taken by Ebb as it skimmed across part of the northern terrain of the Moon’s far side at an altitude of only 6 miles on December 14th 2012. Enjoy.

Fomalhaut and Fomalhaut b (inset) Hubble imagery (Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute))

It’s been an exciting few days for exoplanetary science. A slew of refined statistical measurements of the abundance of other worlds have made it clearer than ever that our galaxy is crammed with planets.

One in six stars should host at least one Earth-sized object in an orbit smaller than that of Mercury, implying that in total there are tens of billions of planets this size across the Milky Way.

But for me one of the most exciting announcements has come from new observations of the Fomalhaut system, a ‘mere’ 25 light years from us. Fomalhaut is a star some ninety percent more massive than the Sun and only a few hundred million years into its time as a hydrogen burning ‘main-sequence’ object.

Back in 2008 Hubble Space Telescope imagery confirmed that not only is Fomalhaut surrounded by a remarkable hoop-like structure of dusty material – encircling this system at more than 120 times the distance of the Earth from the Sun – but revealed that an object possibly of Jupiter size is orbiting at the apparent inner edge of this hoop.

This was quite a claim. It made this planet, Fomalhaut b, one of a mere handful of worlds directly imaged (as opposed to being detected indirectly as the majority of exoplanets are). It also raised a huge question – how could such a planet be on such an enormously large orbit, more than 4 or 5 times further out from its star than Neptune is in our solar system?

The Fomalhaut system in context - comparing to the solar system (Credit: NASA/ESA/A. Feild STScI)

For nature to build a planet in situ at these distances confounds many of our theories about planet formation. The problem was exacerbated by the estimates of the shape of the orbit that suggested it was relatively circular – indicating that the planet had not been flung to this position by earlier dynamical jostling with other planets.

It was indeed puzzling. My colleague Kristen Menou and I had recently prepared a paper where we estimated the rate at which astronomers might expect to find such large worlds on such distant orbits from their stars. The mechanism for their placement that we simulated was an earlier episode of intense gravitational interaction between the original planets around such a star. If planets form efficiently (and they certainly seem to do so) they can start off crammed into the orbital space close to their parent star. But this can result in dramatic gravitational instability, the systems are dynamically ‘hot’. To cool down they collide, eject, and fling planets onto larger orbits.

Dynamical cooling - close packed circular orbits (left) evolve to extended elliptical orbits with fewer planets over millions to tens of millions of years (C. Scharf)

There was a snag though. Our simulations, along with those from another group working on this problem led by Dimitri Veras, indicated that the remnants of such chaos – planets on large orbits – should also have highly non-circular, strongly elliptical orbits. Fomalhaut b did not seem to fit this pattern.

Flash forward to this week. The most recent Hubble imagery of Fomalhaut b, combined with the passage of time and an opportunity to refine the measurements of Fomalhaut b’s orbital path, now suggests that its orbit is in fact elliptical. At its closest passage to its parent star this giant world is estimated to be a ‘mere’ 4.6 billion miles away. At its furthest it reaches about 27 billion miles. Running these numbers indicates an orbital ellipticity, or eccentricity of about 0.7 – a 70% deviation from a circular path.

Our simulations tell us that this kind of orbit is almost precisely what you’d expect in about 5-10% of systems where strong dynamical cooling has taken place (yes, I’m patting myself on the back, along with congratulating my colleagues).

The new observations also reveal possible evidence for signs of another planet in the system that may be ‘slicing’ through this outer dusty hoop of material – it could be a candidate for the world that helped push Fomalhaut b to this orbit. As for Fomalhaut b itself, its mass is unknown, it could be anything between the size of tiny Pluto and Jupiter. It could also be surrounded by a disk or ring of its own, enhancing its apparent brightness.

Time will tell what’s really going on in this system, but it’s turning out to be a wonderful testbed for many ideas.

You look familiar.... (Credit: NY Zoological Society)

About three years ago I had an epiphany, or maybe it was a small bout of lunacy. I realized that I wanted to try to write a real book – something that wasn’t just another peer-reviewed journal article reporting the minutiae of a piece of research that precisely ten other people on the planet were genuinely interested in (one posthumously).

And so I did.

Except it wasn’t quite that straightforward, and I thought I’d share a few experiences with any of you considering taking this plunge.

First, let me be clear that I think that I have been incredibly, almost unbelievably lucky in how things have played out. I have heard so many tales of writer’s struggles, rejections, endless revisions, dodgy agents, brutal editors, and half-realized ambitions that I know my experience has been blissfully free of major hurdles.

So bear that in mind, and take the following collective snippets as simply one report from the trenches of popular science book writing.

The initial steps. Talk to friends and colleagues who’ve already done it and remember; if you’re a scientist you have an implicit advantage because you probably already have something you’re itching to explain to the world, and you probably know more about it than 99.9% of the population without having to lift a finger. Your disadvantage is that, well, you’re a scientist.

Although it’s not too hard to slither into the quasi-academic, quasi-popular market through a university-based publishing house, the world will open up much, much more if you get yourself a literary agent. Not only will they be vastly more knowledgeable than you, they will actually get out there to work on your behalf – a strange and wonderful concept if you’re coming from academia.

How do you get an agent? Talk to colleagues, talk to friends, talk to friends of friends. In my case, and I kid you not, I was led to my wonderful agent through my eldest daughter being in the Girl Scouts and the parent of another Scout being an experienced editor in the publishing business. Talk about serendipity.

Listen to your agent. Yes, put aside your ivory tower king-of-the-castle behavior and do what you’re told.

The initial big piece of advice my agent gave me was to start blogging. I wasn’t convinced that this was important, but (see previous point) I did what I was told. At first it was out on my lonesome and a year later, well, here we are at Scientific American. Best investment of time ever.

If you do blog, take it seriously and consider what people might want to read. Self-involved reportage of ‘my grand life in science’ is in my opinion a total turn-off unless it’s making a point or telling a real story (a rule that I’ll hypocritically ignore in this post). Write about the science, write with some passion, and above all treat it as continual practice for the big stuff. And remember, people who have a general interest in science want to understand – you have a certain responsibility as a purveyor of expert knowledge to communicate that knowledge with some accuracy. It’s not always easy, so be prepared to ‘fess up if you screw up.

It's all about words...

Start thinking about that book proposal. Maybe you already have a brilliant idea? Well, be ready to ditch it like cold coffee if your agent and editors stare at you with ill-disguised blank faces. They really are the experts here and the goal is for people to actually buy and read your book. A good book idea will feel that way to everyone involved, not just your ego.

Be helpful. If your agent says you need something on paper next week, do it. If they suggest you alter text, do it. Go back to behaving like an eager grad student.

If you are in the happy situation that you have an offer for your book – let your agent do the talking and trust that what’s good for them is good for you too. Figure out how long you think you need to write the book. Don’t give yourself too much time because procrastination is your enemy.

Write. I guess everyone has a different approach, but I found that breaking it down to a ‘daily quota’ of words was pretty helpful. By the end of each week assess how much you’ve done and (honestly) how much of it you’ll end up keeping. Be ready to jot down ideas. Don’t put it off no matter how inconsequential it may seem, by the time you’ve finished brushing your teeth you’ll have lost what made it seem so special.

Keep notes. That off-hand comment in a sentence? It may well need a footnote or end note by the time you’re finished, so pause and find a reference, write it down or paste it at the end of the word file. Trust me, you’ll love yourself much more in a few months time. This process is, for me at least, very different than when I write an academic article where ‘doing the references’ always comes last.

Keep reading. Read what you’ve written, read other things, read novels, read science, read blogs, read newspapers (yes, those antiquated things). That flow of words keeps you in the zone. And use every opportunity to practice your own writing, even daily emails present a chance to keep your grammar skills up to snuff – students and colleagues will be amazed at their erudite respondent.

Get feedback, especially from your editor if you can. Better to know that you’ve written the pop-sci equivalent of Soviet metaphysical free verse poetry early rather than late.

Remember your audience. One of the hardest things I’ve found writing popular science is to push past the (imagined) sense of my peers and colleagues looking over my shoulder. I’ve written long pieces only to realize I’ve slipped into academic defensiveness and rambling details that do absolutely nothing to convey the story but respond to anticipated critical questions from my darling fellow scientists. Don’t do it. Write for your intelligent but non-scientific friends. If you don’t have any of those, write for the people who do your taxes or fix your plumbing.

Finished? Hand it over and take a deep breath for approximately two weeks. You still have edits, edits, copyedits, edits of the copyedits, page proofs, 2nd pass proofs, galley proofs, end matter, cover copy, cover design, author bio, author picture (ugh), and much more to come. A 12 month gap between when you thought it was over and a finished product is not unusual.

If you get asked to record the audio version of your book, do it. Yes it’s a few days of exhausting, throat rasping, sensory deprivation inside a triple-glazed sound booth, but you’ll discover that the written word is very different than the spoken word. All those grammatical flourishes and subtle punctuation marks that looked so good in silence now make your tongue twist and your words stumble. It’s hard, but it’s an amazing lesson.

If you are lucky your publisher will care enough to want to help promote and advertise your book. Do anything you can to be helpful. Don’t say ‘I’m unavailable for the next 12 months’, say instead ‘my soul is available for free’. Don’t imagine for an instant that your book will pop like some virtual particle-pair from the vacuum and produce its own successful universe. Nope. Your willingness to go to bat will be vital.

Start figuring out what exactly the book is all about. Yes, really. You might think you know, after all you just wrote it, but now imagine you’re live on air with a radio station on another continent and they’ve just asked you why XYZ is important, and you have 30 seconds to speak.

At the launch and post-launch. Ever go to a bookstore to listen to an author and get a book signed? No, me neither. But you’ll be doing this, sans Powerpoint, sans sleep. Practice talking without notes, practice reading a bit of your book, practice being a performer rather than a lecturer. Remember, your audience may have all been to the pub beforehand (if not, well they probably should have) and you want them to be intrigued enough to part with their hard earned money. Yes, it’s that simple, you have become a salesperson. It’s the good fight though, because you really believe in the scientific story you’ve told and the importance of other people hearing it, right?

Live radio interviews: By phone or remote studio – I don’t know why they think this makes it easy, but producers will play you the live feed before you go on air and speak over it to let you know when you’ll be on. It’s like listening to a brilliant conversation where you have to butt in at precisely the right time with your feeble thoughts. Work hard at removing ‘Um,’ ‘Err’. Figure out more than one way to start a response – ‘So,’ ‘Well,’ and ‘Good question,’ get old very, very quickly.

Yep, that's you.... (Credit: The Strobridge Litho. Co., Cincinnati & New York)

You may give some ‘proper’ presentations – with Powerpoint and the audio-visual works. Science museums or other venues do this, and there is a burgeoning number of science ‘clubs’ springing up. These are almost always great fun, with audiences who are already more or less on your side. Resist the temptation to talk about ‘the book’, instead give people a reason to want to go look at the book because they’re so excited about what they’ve just heard.

Buy good pens. On one of my first signings I pushed too hard with a substandard pen and tore a hole through the precious pages that a loyal reader had just forked over good money for. Not good. Keep pens handy at all times.

Be prepared to do all of the above in a book ‘tour’. This is publisher-speak for a punishing schedule of travel, talking, and signing. It is actually fun, but by the end of it you’ll have no idea which hotel/airport/city/state/country you’re actually in. And then it will all be over.

Keep promoting. There are physical laws determining a book’s life, as far as I can tell. There’s momentum at the start, and as more people actually read the book there is a chance of slowing the natural dissipation of that momentum. There is also randomness. You’ll probably feel like an orphan pressing their face up against the candy-store window as you see other books flare into bursts of glory, even though they’re about the ‘science’ of cat barf. I guess we all deal with these things differently, but remembering that your book is in it for the long haul can help (a good book deal will keep it in print for several years).

Reviews can be good, middling, and bad. Unlike writing peer-reviewed journal articles, there is little real opportunity to rebut what’s said about your precious words out in the cold harsh world. Having said that, I think there’s only been one instance where I really lost any sleep over an appallingly inaccurate and somewhat negative review (whose inaccuracy rather ironically was in its claimed inaccuracies of the book, which it quoted inaccurately…good grief). Take a deep breath, and remember your mother loved you as a baby.

As much as you may hate it, social media can be a writer’s best friend. Facebook lets you make pages for a book, Twitter accounts can be a way to promote your efforts, and all that Google+ stuff may be helpful, if you can figure out what it all means. But the biggest piece of advice, which is the same as with live presentations, is to make stuff intrinsically interesting if you can. I know I’ve succumbed to the ‘Buy this book’ use of Twitter after a depressing glance at my Amazon sales rank (don’t laugh, you’ll be following that obsessively too). It doesn’t really work. Tell your audience something interesting and useful, be that expert-on-call and things will go much better.

Got friends or acquaintances who work in the media world? Time to buy them a drink or compliment them on their latest piece of reality TV dross. Don’t expect anything to happen, but maybe you’ll end up in front of a camera and maybe a viewer will recognize your name on the shelf of their local bookstore or on an Amazon ‘recommends’ list.

If you’re at a university, let them know what you’ve been doing. Some places seem to jump to promote local talent. Even if the response is lukewarm, keep reminding them. Don’t feel dismayed that your colleagues are more popular as writers than you can reasonably hope to be (I inhabit the same campus as Brian Greene and Oliver Sacks, and Neil deGrasse Tyson is just down the road). Just keep working at it.

Finally. The book is on shelves, the reviews are in, and there might just possibly be a royalty check in the mail that’ll pay for your next haircut. It’s decision time. Was it worth it? Has inattention to your research program for the past year and a half produced ill-tempered students and a mountain of unprocessed data? Or do you have a desperate urge to keep writing, keep engaging with a public you’d forgotten existed until the past few months?

It’s your call. For me it’s a no-brainer, I’ll write and I’ll keep being a scientist. The only challenge is how to work 48 hour days when the universe conspires to cycle through day and night on Earth in only 24.

And yes, my new book will be out in 2014. See how I delayed mention of it? I even avoided saying that it’s called The Copernicus Complex, and that it’s all about a rip-roaring quest to discover our significance or insignificance in the cosmos, because it’s important to give your audience some substance instead of endless advertising….