Great Balls of ‘Space Mud’ May Have Built Earth and Delivered Life’s Ingredients

Artist’s impression of the molten surface of early Earth (NASA)

When imagining how our planet formed 4.6 billion years ago from the protoplanetary disk surrounding our sun, images of large pieces of marauding space rock slamming into the molten surface of our proto-Earth likely come to mind.

But this conventional model of planetary creation may be missing a small, yet significant, detail. Those massive space rocks may not have been the conventional solid asteroids — they might have been massive balls of space mud.

This strange detail of planetary evolution is described in a new study published in the American Association for the Advancement of Science (AAAS) journal Science Advances and it kinda makes logical sense.

Using the wonderfully-named Mars and Asteroids Global Hydrology Numerical Model (or “MAGHNUM”), planetary scientists Phil Bland (Cornell University) and Bryan Travis (Planetary Science Institute) simulated the movement of material inside primordial carbonaceous chondrite asteroids — i.e. the earliest asteroids that formed from the sun’s protoplanetary disk that eventually went on to become the building blocks for Earth.

A simulated cross section of a 200-meter wide asteroid showing its internal temperature profile and convection currents (temperatures in Celsius). Credit: PSI

It turns out that these first asteroids weren’t cold and solid lumps of rock at all. By simulating the distribution of rock grains inside these asteroids, the researchers realized that the internal heat of the objects would have melted the icy volatiles inside, which then mixed with the fine dust particles. Convection would have then dominated a large portion of these asteroids, causing continuous mixing of water and dust. Like a child squishing a puddle of dirt to create sloppy “mud pies,” this convection would have formed a ball of, you guessed it, space mud.

Travis points out that “these bodies would have accreted as a high-porosity aggregate of igneous clasts and fine-grained primordial dust, with ice filling much of the pore space. Mud would have formed when the ice melted from heat released from decay of radioactive isotopes, and the resulting water mixed with fine-grained dust.”

In other words: balls of mud held together by mutual gravity, gently convected by the heat produced by the natural decay of radioactive materials.

Should this model hold up to further scrutiny, it has obvious implications for the genesis of life on Earth and could impact the study of exoplanets and their habitable potential. The ingredients for life on Earth originated in the primordial protoplanetary soup, but until now the assumption has been that the space rocks carrying water and other chemicals were solid and frozen. If they were in fact churning away in space as dynamic mud asteroids, they could have been the “pressure cookers” that delivered those ingredients to Earth’s surface.

So the next question would be: how did these exotic asteroids shape life on Earth?


Hayabusa Re-Entry Video: Spacecraft Destruction at its Best

There’s not a lot to add to this video, it’s too awesome.

It was captured by NASA’s converted DC-8 jet that was flying over Australia when the Japanese Hayabusa spacecraft broke up during re-entry. I’ll let the video do the rest of the talking:

Oh yes, and that little dot ahead of the falling debris? That’s the sample return capsule before it was found int he Outback safely. Thank goodness its parachute worked (presumably).

For more spacecraft demolition awesomeness, read “NASA Aircraft Videos Hayabusa Re-Entry

Hayabusa Returns to Earth with a Flash

Hayabusa re-enters over the Australian Outback, generating a bright fireball (screen grabs from the JAXA video feed)

Staring hard at the live streaming video of the black Australian skies, I was hoping to see a faint streak of light glide across the camera’s field of view.

But no, it wasn’t that subtle.

Shortly after 9:51 am EDT on Sunday morning (or, for me, a far more civilized 2:51 pm GMT), the Japanese space agency’s (JAXA) Hayabusa’s mission officially came to an end, burning up in the atmosphere. However, a few hours before, the spacecraft released a 40 cm-wide capsule, sending it ahead of the main spacecraft. This sample return capsule would have a very different re-entry than its mothership.

As I watched the small dot of light on the horizon of the streaming video getting brighter and brighter — feverishly hitting the PRTSC button and using some rapid cut&paste-fu in Photoshop — suddenly it erupted, shedding light on the distant clouds that had been invisible in the night.

Far from the re-entry being a faint or dull event, it was dazzling (as seen in the screen grabs to the right).

So, after seven dramatic years in space, the Hayabusa mission has come to an end.

For the full story about how Hayabusa got hit by the largest solar flare in history, limped to visit an asteroid called Itokawa and how its sample-collecting kit malfunctioned, have a read of my main article on Discovery News: Hayabusa Generates Re-Entry Fireball Over Australia

Note: Thanks to everyone who re-tweeted the sequence of re-entry pics. As of this moment it has received over 30,000 views on Twitpic!

Gecksteroids! Asteroids and Geckos May Share Common Force

The asteroid Itokawa (as imaged by the Japanese Hayabusa probe) and a gecko tattoo. Bear with me, it'll make sense soon (JAXA)
The asteroid Itokawa (as imaged by the Japanese Hayabusa probe) and a gecko tattoo. Bear with me, it'll make sense soon (JAXA)

What do asteroids and geckos have in common? Not a lot, as you’d expect, but they may share a common force.

This rather strange notion comes from research being done by a team of University of Colorado scientists who have been studying the odd nature of the asteroid Itokawa. When the Japanese Hayabusa mission visited the space rock in 2005 (Hayabusa’s sample return capsule is set to return to Earth on June 13th by the way), it noticed the asteroid was composed of smaller bits of rubble, rather than one solid chunk. Although this isn’t a surprise in itself — indeed, many asteroids are believed to be floating “rubble piles” — the rate of spin of the asteroid posed a problem.

Itokawa spins rather fast and if only the force of gravity was keeping the lumps of rock together, they would have been flung out into space long ago. In short, the asteroid shouldn’t exist.

Although plenty of theories have been bandied around, one idea seems to stick.

More commonly found as a force that holds molecules together, the van der Waals force may bind the individual components of the asteroid together, acting against the centripetal force caused by its spin.

But where do the geckos come in?

Geckos are highly skilled in the “climbing up walls” department, and it’s the van der Waals force that makes this happen. Should the body of a gecko be tilted in such a way against a perfectly smooth, “impossible” to climb surface, the gravity acting on the little creature will trigger the force into action. Therefore geckos have evolved to exploit the practical application of van der Waals.

This has some rather interesting ramifications for asteroid evolution too. During early stages of asteroid formation, the larger fragments of rock are flung off; the centripetal force exceeds that of gravity. In the latter stages of development, only the smallest rocks remain behind, their mass small enough to allow van der Waals forces to overcome the spin.

So, there you have it, asteroids do have something in common with geckos. It seems only right to call these space rubble piles “Gecksteroids.”

Thanks to my Discovery News colleague Jennifer Ouellette for drawing the comparison between asteroids and geckos!

Source: Discovery News,

NASA’s Asteroid Mission: Scary but Useful

Things have been moving fast for NASA in recent weeks, culminating in President Obama’s inspiring speech at Kennedy Space Center on Thursday. I haven’t commented on the new direction for the US space agency’s direction thus far as I’ve needed some time to digest the ramifications of these plans. But generally, I’m positive about the scrapping of the moon goal in favor of a manned asteroid mission (by 2025) and Mars some time around 2035.

But it hasn’t been easy, especially after the Ares I-X test launch in October 2009.

The Ares I-X was the first new NASA manned vehicle my generation has seen take to the skies (I was only one year old when the first of the shuttle fleet launched, beginning nearly 30 years of low-Earth orbit operations, so that doesn’t count). Despite criticism that this test flight was nothing more than old tech dressed up as a sleek “new” rocket, I was thrilled to see it launch.

The end product didn’t matter on that day. Sure, we’ve been to the Moon before, but it just seemed like the best plan on the table. I was inspired, I felt excited about our future in space. Seeing how astronauts live and work on the lunar surface, using it as a stepping stone for further planetary exploration (i.e. Mars) seemed… sensible. Expensive, but sensible

But the overriding sentiment behind Obama’s new plans was that we’ve been there before, why waste billions on going back? Continuing with the bloated Constellation Program would have used up funds it didn’t have. Cost overruns and missed deadlines were already compiling.

So, the White House took on the recommendations of experts and decided to go for something far riskier than a “simple” moon hop. Things going to plan and on schedule, in the year 2025 we’ll see a team of astronauts launch for a much smaller and far more distant target than the moon.

The asteroid plan has many benefits, the key being that we need to study these potentially devastating chunks of rock up close. Should one be heading in the direction of Earth, it would be really nice to have the technological ability to deal with it. A manned mission may be necessary to send to a hazardous near-Earth asteroid. Think Armageddon but with less nukes, no Bruce Willis, but more science and planning. Besides, if a rock the size of a city is out there, heading right at us, I’m hopeful we’ll have more than 18 days to deal with the thing.

My Discovery News colleague Ray Villard agrees:

“A several month-long human round trip to an asteroid will test the sea legs of astronauts for interplanetary journeys. And, asteroids are something we have to take very seriously in coming up with an Earth defense strategy, so that we don’t wind up going extinct like the dinosaurs.”

Possibly even more exciting than the asteroid plan is what — according to Obama — will happen ten years after that: a manned mission to Mars. I can’t overemphasize my enthusiasm for a mission to the Red Planet; that will be a leap for mankind like no other. Granted, there is plenty of criticism flying around that we need to live on the moon first before we attempt to land on Mars, but looking at the new plan, we won’t be actually landing on Mars any time soon. A 2030’s mission to Mars will most likely be a flyby, or if we’re really lucky, an orbital manned mission.

And that’s why going to an asteroid will be a good first step. Spending months cramped inside a spaceship with a handful of crewmates will likely be one of the biggest challenges facing man in space, so popping over to a near-Earth asteroid first is a good idea. A Mars trip could take over a year (depending on the mission). Now, this is where technological development sure would help.

If NASA can plough dedicated funds into new technologies, new life support and propulsion systems can be developed. Those two things will really help astronauts get places quicker (avoiding boredom) and live longer (avoiding… death). For the “living longer” part, there appears to be genuine drive to increase the life of the space station and do more impressive science on it. As it’s our only manned outpost, perhaps we’ll be able to use it for what it’s designed for.

There are a lot of unknowns still, and Obama’s Thursday speech certainly wasn’t NASA’s silver bullet, but it’s a start. Allocating serious funding for space technology development whilst setting the space program’s sights on going where no human has been before will surely boost enthusiasm for space exploration. In fact, I’d argue that this is exactly what NASA should be doing.

Although I was dazzled by the Ares I-X, I can see that continuing with Constellation would have been a flawed decision. Launching a manned mission to explore an interplanetary threat sounds risky, but considering that asteroids are the single biggest cosmic threat to civilization, it sure would be useful to know we have the technology to send astronauts to asteroids, perhaps even dealing with a potential threat in the near future.

P/2010 A2 Was An Asteroid Collision (Says Hubble)

What you see here is something mankind has never seen before, the aftermath of an asteroid collision. This conclusion comes after the Hubble Space Telescope was commanded to take a closer look at a strange comet-like object pottering around in the asteroid belt between the orbits of Mars and Jupiter.

The truth is we’re still struggling to understand what this means,” said David Jewitt, a planetary physicist from UCLA. “It’s most likely the result of a recent collision between two asteroids.”

After P/2010 A2 was discovered in January, Jewitt managed to get observation time on Hubble to get a closer look of what was thought could be a rare asteroid-comet hybrid.

In the image, the object named P/2010 A2 has a very obvious “X” on its surface shaped pattern in its tale, possibly the location where a smaller body slammed into it at high speed. The result of this hyper-velocity impact produced a lot of debris and scientists think the comet-like tail being swept back by the pressure of the solar wind is dust and outgassing volatiles (like subliming water ice).

Although this kind of event has never been observed before, over the lifetime of the evolving solar system, events like this occur on a regular basis, in fact asteroid collisions have shaped the asteroid belt. Interestingly, it is thought this impact was caused by a collision of a “Flora family” asteroid, a type of object that may have wiped out the dinosaurs 65 million years ago. (Don’t worry, this collision won’t affect Earth in any way, the dinosaur thing is simply an interesting connection!)

What an incredible discovery, it’s fortunate that we have Hubble’s excellent eyesight to peer deep into the asteroid belt…

Sources: Reuters, Discovery News

Could P/2010 A2 be the First Ever Observation of an Asteroid Collision?

Something rather bizarre was observed in the asteroid belt on January 6. Ray Villard at Discovery News has just posted an exciting article about the discovery of a comet… but it’s not your average, run-of-the-mill kinda comet. This comet appears to orbit the Sun, embedded in the asteroid belt.

Comets don’t usually do that, they tend to have elliptical and inclined orbits, orbits that carry them close to the Sun (when they start to heat up, creating an attractive cometary tail as volatile ices sublimate into space, producing a dusty vapor). They are then flung back out into the furthest reaches of the Solar System where the heating stops and the comet tail disappears until the next solar approach.

But P/2010 A2 — discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey — has a circular orbit and it still appears to be venting something into space.

P/2010 A2 (LINEAR): A comet or asteroid debris? (Spacewatch/U of Arizona)

There is the possibility that it is a member of a very exclusive bunch of objects known as main belt comets (MBCs). MBCs are confused asteroid/comet hybrids that appear to spontaneously vent vapor and dust into space and yet stay confined to the asteroid belt. But, if P/2010 A2 is confirmed to be one of these, it will only be the fifth such object to be discovered.

So what else could it be? If the potential discovery of an MBC doesn’t excite you enough, it could be something else entirely: the dust produced by a hyper-velocity impact between two asteroids. If this is the case, it would be the first ever observation of an asteroid impact in the Solar System.

The asteroid belt isn’t the same asteroid belt you might see in science fiction; although there are countless rocky bodies in our asteroid belt, it is rare that these rocky bodies encounter each other. Space is very big, and although the density of asteroids in this region might be considered to be “high”, this is space we’re talking about, you can fly a spaceship through the region without having to worry that you’ll bump into something. The average distance between asteroids is huge, making it a very rare occurrence any two should hit. But given enough asteroids, and enough time, eventually asteroid collisions do happen. And in the case of P/2010 A2, we might have been lucky.

Asteroid collisions: Rare, but possible.
Asteroid collisions: Rare, but possible.

The chatter between comet/asteroid experts is increasing, and on one message board posting, Javier Licandro (Instituto de Astrofísica de Canarias, Spain) reports observing a secondary asteroid traveling with the cloud-like P/2010 A2.

The asteroid moves in the same direction and at the same rate as the comet,” reports Licandro on The Minor Planet Mailing List. “In addition, the P/2010 A2 (LINEAR) image does not show any central condensation and looks like a ‘dust swarm’.”

A short lived event, such as a collision, may have produced the observed dust ejecta.”

Therefore, this ‘comet’ may actually be the debris that was ejected after a collision between two asteroids. Although these are preliminary findings and it’s going to take some serious observing time to understand the true nature of P/2010 A2, it’s exciting to think that we may just have observed an incredibly rare event, 250 million miles away.

Source: Discovery News

xkcd: Probably Not The Best Way To Deal With An Asteroid


I hope we never see this day in the future, when the newscaster calmly informs us that an asteroid is on a collision course with Earth.

In any case, if this scenario did unfold, I’d like to think we’ll have the in-space technological capability to deal with the threat — but if we didn’t, I’m sure we’d work on it pretty damn quickly (given enough warning… if not… well, I’m out of ideas).

But please… don’t go strapping a nuclear warhead to the rock… it might not end quite so well.

Source: xkcd

Mining Asteroids: Not At Those Overheads

Where shall we start diggin'?

In The Future™, when mankind is Sufficiently Advanced®, nations, companies and entrepreneurs will be shuttling huge cargo spaceships to and from the asteroid belt. Asteroid mining is going to be the first REAL gold rush, “thars gold in them thar rocks!” But not only gold, we’ll be able to consume asteroids of all their constituents; platinum, iridium and silicon (silicon?). Global economies will be flooded with a new-found wealth being fed by the new Solar System’s bounty. Times will be good, after all, this is The Future™.

Although asteroid mining looks good on paper, once you do a little bit of adding up, you suddenly realize it’s actually one hell of an undertaking. Looking at the economics of asteroid mining is especially daunting, and believe me, my co-author Greg Fish has done the number crunching.

When Greg and I started out researching our book, Astroeconomics: Making Money from the Vacuum of Space, we initially made the assumption that the key way to make vast wads of cash in space is from asteroid mining. This assumption was purely based on… well, an assumption. A quick glance on the various space advocacy websites will demonstrate just how accepted asteroid mining is as a future industry. After all, science fiction has been telling us this for years. Given a sufficiently advanced technology, we’ll be able to build a spaceship, with a mining platform, send it to the asteroid belt (obviously a very short distance), fill up the cargo hold with ore (or, if we are that advanced, refined precious metals) and be back on Earth by a week next Friday.

However, when we looked at the situation, we decided to focus on the economics of the beast (in all honesty, Greg did the calculations, I can barely balance my own books, let alone the books of an entire space-faring industry).

Naturally, we assume it’s going to be businesses (not governments) wanting to mine asteroids, and we assume mining/spaceflight technologies that could possibly be available within the next few decades (and no, we didn’t consider nanotech; I’m thinking rock-eating nanobots wont be available in stores for a long while yet). We also assumed these space mining companies will want to make a profit (we might be wrong). Unfortunately, asteroid mining doesn’t make an awful lot of sense from a business perspective. The risk is too high, the overheads are whopping, and the payback — while impressive — won’t pay the bills. And then there’s nasties like space pirates and industrial accidents to consider, adding to the ‘risk’ factor.

All in all, it’s not a very attractive business proposition to build a mining fleet and send it on an interplanetary joyride; most businesses would rather set up a mining installation in the middle of Antarctica. But we’re not pouring cold water on the whole venture either, we’ve worked out a few ways future businesses can actually turn asteroid mining into an industry.

So, today, Greg contributed a guest article to my “other” blog, Space Disco on Discovery Space. If you want to find out more about the ins and outs of asteroid economics, have a read of Mining Asteroids And Getting Rich (Or Not)


Asteroid Tanning in the Solar Wind Salon

Asteroids tan fast in the solar wind (ESO)

In a study carried out by European Southern Observatory (ESO) scientists, it was found that asteroids are susceptible to sunburn. By comparing the material found inside meteorites here on the ground with the colour of asteroids floating in space, there is a huge difference; the asteroids in space are redder.

So far, this might not be too surprising, after all, the surface of Mars is red with ferrous oxides (rust), why shouldn’t asteroids be red too? Actually, asteroids aren’t necessarily made of the same stuff as Mars, and they aren’t getting tanned due to the Sun’s ultraviolet rays; asteroids are bathed in ionizing solar wind particles, causing the asteroid’s surfaces to redden over a period of time. And that period is short when compared with Solar System time scales. It only takes a million years for the surface of young asteroids (born from energetic asteroid collisions) to weather under the constant barrage of particles from the solar wind.

This has some interesting implications for asteroid studies. Possibly the most striking factor this study uncovers is the nature of near-Earth asteroids that have been observed exhibiting comparatively “young” surfaces, apparently free from solar wind reddening. Previously, astronomers have agreed that these young surfaces were down to recent asteroid collisions. However, the period of the solar wind tanning effect is much shorter than asteroid collision frequency. So even if two asteroids collided, in all likelihood, if we observed one of these asteroids, the solar wind would have weathered the surface back to its reddened state.

It turns out that some near-Earth asteroids have “young” surfaces due to gravitational interactions with planets as they pass. When this happens, the red dust is “shaken off”, revealing the untouched rock beneath.

For more, check out my article Young Asteroids Age Fast with a Solar Wind Tan on the Universe Today.