Coolest White Dwarf Is a Glimpse of What Happens Long After Our Sun Dies

All good things come to a cold and dusty end.

[NASA’s Goddard Space Flight Center/Scott Wiessinger]

“So, what do you think happens after you die?”

The question was more of an accusation. The lady asking was sitting across from me at a Christmas dinner a friend of mine was hosting and the previous query was one about my religion. She wasn’t impressed by my response.

Granted, it probably wasn’t the ideal setting to say that I was an atheist, but I wasn’t going to lie either.

“Um, well…” I remember feeling vulnerable when I responded, especially as I’d only just met half the dozen people in the room, including the lady opposite, but I remember thinking: stick with what you know, Ian. So, I continued: “When I’m dead, all the elements from my body will remain on Earth,” — I didn’t want to go into much detail about my real plan of having my remains blended up into a jar and then launched into space (more on that in a future post, possibly) — “and those elements will get cycled through the biosphere through various biological, chemical and physical processes for billions of years. Eventually, however, all good things must come to an end and the sun will run out of fuel, ballooning into a huge red giant star, leaving what is known as a white dwarf in its wake.” (By her glazed look, I could tell she regretted asking, but I continued.) “If, and it’s a big IF, the Earth survives this phase of stellar death, our planet might be hurled out of the solar system. Or, and this is my favorite scenario,” — I’d hit my stride and everyone else seemed to be entertained — “it might careen inward, toward the now tiny white dwarf sun, where Earth will be ripped to sheds under powerful tidal forces, sending all the rocks, dust, and the elements that used to be my body, raining down onto the white dwarf.”

This is an abridged version. I also went into some white dwarf science, why planetary nebulae are cool, and how our sun as a white dwarf would stand as a monument to the once great solar system that will be gone five billion years from now. The recycled elements from my long-gone body could eventually rain down onto the atmosphere of a newborn white dwarf star — pretty cool if you ask me. This might be more of a cautionary tail about inviting an atheist astrophysicist to religious celebrations, but I feel my tabletop TED talk was good value for money. And besides, by turning that inevitable “what religion are you?” question into a scientific one, I hadn’t gotten bogged down with justifying why I’m an atheist — a conversation that, in my experience, never works out well over dinner.

So, why am I remembering that fun evening many years ago? Well, today, there’s some cool white dwarf news. And I love white dwarf news, especially if it’s about dusty white dwarfs. Because dusty white dwarfs are a reminder that nothing lasts forever, not even our beautiful 5-billion-year-old solar system.

One Cool Dwarf

A citizen scientist working on the NASA-led “Backyard Worlds: Planet 9” project has discovered the coldest and oldest white dwarf ever found. The project’s aim is to seek out as-yet-to-be-discovered worlds beyond the orbit of Neptune (re: “Planet Nine” and beyond). Through the analysis of infrared data collected by NASA’s Wide-field Infrared Survey Explorer, or WISE (inspired by data from the European Gaia mission), Melina Thévenot was looking for local brown dwarfs — failed stars that lack the mass to sustain nuclear fusion in their cores, but pump out enough infrared radiation to be detected. In the observations, Thévenot spied what she thought was bad data, but with the help of WISE, she found not a nearby brown dwarf, but a white dwarf that was brighter and further away. After sharing her discovery with the Backyard Worlds team, astronomers at the W. M. Keck Observatory confirmed that not only was that white dwarf lowest temperature specimen yet found, it was also very dusty. In fact, it’s thought that the white dwarf, designated LSPM J0207+3331, has multiple dusty rings. Its discovery, however, is something of a conundrum and the researchers think it may challenge planetary models.

“This white dwarf is so old that whatever process is feeding material into its rings must operate on billion-year timescales,” said astronomer John Debes, at the Space Telescope Science Institute in Baltimore, in a NASA statement. “Most of the models scientists have created to explain rings around white dwarfs only work well up to around 100 million years, so this star is really challenging our assumptions of how planetary systems evolve.”

Interesting side note: It was Debes who first got me excited about dusty white dwarfs when I met him at the 2009 American Astronomical Society (AAS) meeting in Long Beach, Calif. You can read my enthusiastic Universe Today article I wrote on the topic here.

After deducing the tiny Earth-sized star’s cool temperature — 10,500 degrees Fahrenheit (5,800 degrees Celsius) — the researchers estimate that the white dwarf is approximately 3-billion years old. The infrared signal suggests a copious quantity of dust is present, which is a bit weird. As I alluded to in my tabletop TED talk, after a sun-like star runs out of fuel and puffs up into a red giant, it will leave a shiny white dwarf surrounded by a planetary nebula in its wake. Should any mangled planet, asteroid or comet that survived the red giant phase stray too close to that white dwarf, it’ll get shredded. So, it’s poignant when astronomers find dusty white dwarfs; it means those star systems used to have some kind of planetary system, but the white dwarf is in the process of destroying it. That is the inevitable demise of our solar system in 5 billion years time. But to find a 3-billion-year-old specimen with a ring system doesn’t make a whole lot of sense — the white dwarf had plenty of time to consume all that dusty debris by now, a process, according to Debes, that should only take 100 million years to complete.

Debes, who led the study published in The Astrophysical Journal on Feb. 19, and his team, including discoverer and co-author Thévenot, has some idea as to what might be going on, but more research is needed. One hypothesis is that J0207’s dusty ring is composed of multiple rings with two distinct components, one thin ring just at the edge of where the star is breaking up a belt of asteroids and a wider ring closer to the white dwarf. It’s hoped that follow-up observations by the next generation of space telescopes, such as NASA’s James Webb Space Telescope (JWST), will be able to deduce what those rings are made of, thus helping astronomers understand the evolution of these ancient star systems.

Besides being the ultimate way to gain perspective on our tiny existence (and an excellent topic for an awkward dinner conversation), this research underpins a powerful way in which citizen scientists are shaping space science, particularly projects that require many human brains to process vast datasets.

“That is a really motivating aspect of the search,” said Thévenot, who is one of more than 150,000 volunteers who works on Backyard Worlds. “The researchers will move their telescopes to look at worlds you have discovered. What I especially enjoy, though, is the interaction with the awesome research team. Everyone is very kind, and they are always trying to make the best out of our discoveries.”

Faint Fossil Found in Solar System’s Suburbs

A tiny rock has been detected in the Kuiper belt, which may not seem like such a big deal, but how it was found is.

[NASA, ESA, and G. Bacon (STScI)]

We think we have a pretty good handle on how planets form. After the birth of a star, big enough clumps of dust and rock in the disk of leftover debris begin to accrete mass until they turn into spheres under the pull of their own gravity, jostling around, pushing smaller protoplanets out of the way and being shoved aside by, or smashing, into larger ones. Whatever planets survive this messy process end up becoming a solar system. We’ve seen this around other stars and aside from a few interesting twists on this model, we think we know what’s going on pretty well by now.

But there was one piece missing. The math says that to start the planet building process, you need a kind of planetary seed between one and ten kilometers wide. Since we happen to live in a solar system, we should be able to look outwards, towards the Kuiper Belt, which we think is made primarily from the leftovers of planetary formation, and see these protoplanetary fossils drifting across the sky. However, the process has proven to be rather tricky. These rocks are very faint and rather small compared to everything else we can usually see, so looking for them is kind of like trying to spot a grain of dust in a room illuminated only by moonlight, which is why we have so much trouble finding them.

Or at least we did until now, when a 1.3 kilometer Kuiper Belt Object, or KBO was spotted by a simple setup and commercially available cameras as it eclipsed background stars. While that might not sound like much right now, it’s actually an extremely important finding. First, it tells us how to find tiny KBOs so we can take a proper survey of protoplanetary leftovers. Secondly, it shows that we’re correct in our solar system formation model and demonstrated that predicted artifacts of baby planets that never quite made it do exist. The next part will be to try and detect more of these little planet seedlings to figure out how efficient the formation process is, and see what we can learn from that.

As noted, these finds don’t just apply to our own solar system, but to pretty much every planet in the universe. Just consider that mighty gas giants with swirling storms that could swallow Earth whole, exotic icy dwarfs with percolating cryovolcanoes and towering peaks dusted with reddish organic molecules, and tropical worlds with deep oceans teeming with life — which might even be home to an alien civilization living through its heyday — all started out as these little rocks lucky enough to clump together for a few hundred million years, find a stable orbit, and cool down enough to become a cosmic petri dish. They might not be impressive or exciting on their own, but that doesn’t mean they aren’t profoundly important.

Reference: Arimatsu, K., et. al., (2019) A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes, Nature Astronomy Letters, DOI: 10.1038/s41550-018-0685-8

[This article originally appeared on World of Weird Things]

Hitching a Ride on an ‘Evolving Asteroid’ to Travel to the Stars

The interstellar asteroid spaceship concept that would contain all the resources required to maintain a generations of star travelers (Nils Faber & Angelo Vermeulen)

When ʻOumuamua visited our solar system last year, the world’s collective interest (and imagination) was firing on all cylinders. Despite astronomers’ insistence that asteroids from other star systems likely zip through the solar system all the time (and the reason why we spotted this one is because our survey telescopes are getting better), there was that nagging sci-fi possibility that ʻOumuamua wasn’t a natural event; perhaps it was an interstellar spaceship piloted by (or at least once piloted by) some kind of extraterrestrial — “Rendezvous With Rama“-esque — intelligence. Alas, any evidence for this possibility has not been forthcoming despite the multifaceted observation campaigns that followed the interstellar vagabond’s dazzling discovery.

Still, I ponder that interstellar visitor. It’s not that I think it’s piloted by aliens, though that would be awesome, I’m more interested in the possibilities such objects could provide humanity in the future. But let’s put ʻOumuamua to one side for now and discuss a pretty nifty project that’s currently in the works and how I think it could make use of asteroids from other stars.

Asteroid Starships Ahoy!

As recently announced by the European Space Agency, researchers at Delft University of Technology, Netherlands, are designing a starship. But this isn’t your run-of-the-mill solar sail or “warpship.” The TU Delft Starship Team, or DSTART, aims to bring together many science disciplines to begin the ground-work for constructing an interstellar vehicle hollowed out of an asteroid.

Obviously, this is a long-term goal; humanity is currently having a hard enough time becoming a multiplanetary species, let alone a multistellar species. But from projects like these, new technologies may be developed to solve big problems and those technologies may have novel applications for society today. Central to ESA’s role in the project is an exciting regenerative life-support technology that is inspired by nature, a technology that could reap huge benefits not only for our future hypothetical interstellar space fliers.

Called the MELiSSA (Micro-Ecological Life Support System Alternative) program, scientists are developing a system that mimics aquatic ecosystems on Earth. A MELiSSA pilot plant in Barcelona is capable of keeping rat “crews” alive for months at a time inside an airtight habitat. Inside the habitat is a multi-compartment loop with a “bioreactor” at its core, which consists of algae that produces oxygen (useful for keeping the rats breathing) while scrubbing the air of carbon dioxide (which the rats exhale). The bioreactor was recently tested aboard the International Space Station, demonstrating that the system could be applied to a microgravity environment.

Disclaimer: Space Is Really Big

Assuming that humanity isn’t going to discover faster-than-light (FTL) travel any time soon, we’re pretty much stuck with very pedestrian sub-light-speed travel times to the nearest stars. Even if we assume some sensible iterative developments in propulsion technologies, the most optimistic projections in travel time to the stars is many decades to several centuries. While this is a drag for our biological selves, other research groups have shown that robotic (un-crewed) missions could be done now — after all, Voyager 1 is currently chalking up some mileage in interstellar space and that spacecraft was launched in the 1970’s! But here’s the kicker: Voyager 1 is slow (even if it’s the fastest and only interstellar vehicle humanity has built to date). If Voyager 1 was aimed at our closest star Proxima Centauri (which it’s not), it would take tens of thousands of years to get there.

But say if we could send a faster probe into interstellar space? Projects like Icarus Interstellar and Breakthrough Starshot are approaching this challenge with different solutions, using technology we have today (or technologies that will likely be available pretty soon) to get that travel time down to less than one hundred years.

One… hundred… years.

Sending robots to other stars is hard and it would take generations of scientists to see an interstellar mission through from launch to arrival — which is an interesting situation to ponder. But add human travelers to the mix? The problems just multiplied.

The idea of “worldships” (or generation ships) have been around for many years; basically vast self-sustaining spaceships that allow their passengers to live out their lives and pass on their knowledge (and mission) to the next generation. These ships would have to be massive and contain everything that each generation needs. It’s hard to comprehend what that starship would look like, though DSTART’s concept of hollowing out an asteroid to convert it into an interstellar vehicle doesn’t sound so outlandish. To hollow out an asteroid and bootstrap a self-sustaining society inside, however, is a headache. Granted, DSTART isn’t saying that they are actually going to build this thing (their project website even states: “DSTART is not developing hardware, nor is it building an actual spacecraft”), but they do assume some magic is going to have to happen before it’s even a remote possibility — such as transformative developments in nanotechnology, for example. The life-support system, however, would need to be inspired by nature, so ESA and DSTART scientists are going to continue to help develop this technology for self-sustaining, long-duration missions, though not necessarily for a massive interstellar spaceship.

Hyperbolic Space Rocks, Batman!

Though interesting, my reservation about the whole thing is simple: even if we did build an asteroid spaceship, how the heck would we accelerate the thing? This asteroid would have to be big and probably picked out of the asteroid belt. The energy required to move it would be extreme; to propel it clear of the sun’s gravity (potentially via a series of gravitational assists of other planets) could rip it apart.

So, back to ʻOumuamua.

The reason why astronomers knew ʻOumuamua wasn’t from ’round these parts was that it was moving really, really fast and on a hyperbolic trajectory. It basically barreled into our inner star system, swung off our sun’s gravitational field and slingshotted itself back toward the interstellar abyss. So, could these interstellar asteroids, which astronomers estimate are not uncommon occurrences, be used in the future as vehicles to escape our sun’s gravitational domain?

Assuming a little more science fiction magic, we could have extremely advanced survey telescopes tasked with finding and characterizing hyperbolic asteroids that could spot them coming with years of notice. Then, we could send our wannabe interstellar explorers via rendezvous spacecraft capable of accelerating to great speeds to these asteroids with all the technology they’d need to land on and convert the asteroid into an interstellar spaceship. The momentum that these asteroids would have, because they’re not gravitationally bound to the sun, could be used as the oomph to achieve escape velocity and, once setting up home on the rock, propulsion equipment would be constructed to further accelerate and, perhaps, steer it to a distant target.

If anything, it’s a fun idea for a sci-fi story.

I get really excited about projects like DSTART; they push the limits of human ingenuity and force us to find answers to seemingly insurmountable challenges. Inevitably, these answers can fuel new ideas and inspire younger generations to be bolder and braver. And when these projects start partnering with space agencies to develop existing tech, who knows where they will lead.

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