Friday, November 21, 2008

Another Young Planet Imaged?? In Beta Pic??

They seem to be coming fast and furious now -- which is expected, since the minute someone finds a winning formula, everyone tries to duplicate it.  A French team appears to have imaged a large gas giant (8x the mass of Jupiter) inside the dust debris disk surrounding the famous young star Beta Pictoris using the VLT (Very Large Telescope) in Chile.  The planet is apparently 8 AU (AU=Earth-Sun distance) from its parent star, which is supposedly the exact distance needed to explain the dynamics of the dust in the disk.

The reason I'm using these qualifiers is that unlike the previous detections, this one has not been confirmed by a second set of observations at a later time (in order to track the motion of the planet).  They are using arguments like "It's in the same orbital planet as the disk, and it's the right distance away, and... I really want it to be a planet...", but until they have conclusive proof that the object is actually bound to the star, this will have to be considered a "planet candidate".

But they are definitely right that it would fit in very nicely with previous results.  The Beta Pic disk is one of the most well-studied debris disks, and has long been known to have a very distinctive warp (see pic here) that is explained well by a planet on an inclined orbit at less than 20 AU (paper here).  However, we have no idea if the imaged object is on an inclined orbit, a circular orbit, an eccentric orbit, or any other kind of orbit - we have no information.  So we're going to have to wait and see if all the pieces fit together.

Wednesday, November 19, 2008

So, this is a post not about space specifically, but about popularizing science (which is another secret passion of mine - along with Fritos corn chips and the TV show Fringe - not in that order). I think it's fantastic that more people, both in academia and media, are talking about science in new ways that are tailored specifically for the new YouTube era.  From more weighty endeavors such as the Apple iTunesU (free online videos from university professors) and ScienceDebate2008 (harnessing the election obsession to shine the spotlight on how important science is to our country and our lives), to short science-oriented videos such as Slate's Grand Unified Weekly (a weekly update on cool science news, with flashy graphics), people are really getting energized about putting science front-and-center.  I personally think the obvious difference between the two presidential candidates on important science topics (even if they weren't pitched as science topics) made a big impact on the election, and I hope we can keep ratcheting up the exposure.  The more people realize how science makes life better, the more support science will receive.

Tuesday, November 18, 2008

A follow-up to the post from Friday about the new images of extra-solar planets:  a new paper coming out today searched for additional massive planets around Fomalhaut (the one with the planet at ~100 AU) and didn't find any between 15 AU and 40 AU (remember, an AU is an Earth-Sun distance).  The upper limit on mass is 2x that of Jupiter, so the search wasn't that sensitive (our whole Solar System would be undetectable), but it does at least tell us that the system isn't just an incredibly massive freak of nature.  So we're still left with the problem of how a massive planet (0.5 MJup or larger) would form at 100 AU in a normal planetary system.  More to come... 

Monday, November 17, 2008

OK, I've been newly energized by the first images of planets announced last week - plus I've finally started reading new research papers again - so I'm going to try to get back to writing a new post consistently.  Probably not every day, but whenever I see some new research that could use a nice little summary.

So here's today's new work - a paper on nano-diamonds in protoplanetary disks.  They observe the infrared signature of the dust particles at the exact wavelength coincident with the vibration of carbon-hydrogen bonds in diamond.  This isn't the first time emission from diamond has been observed, but so far there are only three objects that show it.  The diamond emission comes from the inner disk in stars that are bathed in X-ray radiation from low-mass companion stars - this heavy irradiation is required to turn the carbon molecules into diamond rather than graphite.  The current work nails this explanation by resolving different regions with diamond emission (inner disk) compared with non-diamond emission (outer disk).

You can use this idea to trace the disk chemistry - a very specific molecular structure can help tightly constrain the vertical disk structure and radiation environment - but it's not going to get you rich. The diamond particles are about 100 nm, which is the same size as your cellular chromosomes - kind of hard to put into an engagement ring.

Thursday, November 13, 2008

First Light from Planets!

It seems like they've finally done it:  an unambiguous image of an extrasolar planet (actually, several of them) around a main-sequence star (HR8799).  They've been getting close for several years - the image of 2M 1207b was an excellent start, but was often disparaged because 1) the imaged object (b) orbits a brown dwarf (a) rather than a "normal" star and 2) the mass of (b) may be large enough to place it in the brown dwarf range as well.  These new detections (as well as the detection of a planet around a well-known young star named Fomalhaut announced at the same time) have none of these uncertainties - the planet masses are well below the mass limit for a brown dwarf (~13x the mass of Jupiter), and the stars are both A-type main-sequence stars (1.5 - 2x the mass of our Sun).  Unless there turns out to be a major screw-up, the era of direct detection of exo-planets has begun!

Now let's turn to what's interesting about these two systems.  First, both stars are quite young (less than 100 Myr) - this means their planets are still hot from their formation, making them easier to detect.  It also means that much of the debris from planet formation still remains in the system, in the form of dust rings surrounding the planets.  These dust rings are much, much brighter than the planets themselves due to the much higher surface area available to radiate (look at the picture of Fomalhaut for a good idea of this), and this has lead many researchers to design ways to search for the presence of planets around young stars by looking for patterns in the dust created by their orbits.  These new detections corroborate these techniques - patterns can be seen in the dust that can be directly attributed to the planet, and help constrain the mass of the planet.

The second (and I think more interesting) fact is that all the planets are at very large distances from their parent stars - the three planets around HR8799 are between 25 and 70 AU (astron. units - Earth-Sun distance), while the planet around Fomalhaut has an orbital radius of 100 AU!!  For reference, the farthest giant planet in our own Solar System (Neptune) is thought to have formed at 15 AU from the Sun.  How do these massive planets form so far out?  Is it because the stars are larger?  This seems like it might explain the planet at 25 AU, but the others are really pushing it.  Do they form like stars - by collapsing out of the young protostellar cloud?  These planets form the opposite endpoint of the "Hot Jupiter" planets first discovered by radial velocity surveys - and they look like they will have the same mind-blowing effect on the planet formation community.

Tuesday, June 3, 2008

Baby Planet Around a Baby Star

A new frontier in planet detection has now been breached! The first almost-Earth-mass planet has been discovered orbiting a sub-stellar primary object - more commonly called a 'brown dwarf' (a name coined by Jill Tarter, for all you SETI aficionados).  A decent review by can be found here, but the article makes the mistake of calling the host star a 'normal star'.  In fact, brown dwarfs are more like giant planets than normal stars - they span the mass range between gas giant planets (like Jupiter) and very-low-mass stars, with very cool surface temperatures and low luminosity.  For a long time they were considered to be an exotic stellar species - they weren't detectable in visible light, and some theorists speculated that they couldn't be formed at all in stellar clusters.  With the advent of very sensitive infrared telescopes, detecting brown dwarfs is like shooting fish in a barrel - but finding a planet around one is a rare feat.

This discovery puts an exclamation point on the idea that low-mass stars can form planets - which is both a little surprising and a very good thing for planet detection.  If we believe that the amount of protoplanetary material scales with stellar mass, and our Solar System had just enough material to form our current suite of planets, then we would end up finding very few planets around smaller stars (there just wouldn't be enough stuff).  However, this seems to not be the case - planet-hunters are finding lots of planets around low-mass stars (see the Extrasolar Planets Encyclopedia for a full count). This has been perplexing for planet formation theory (we're still working on it), but has been cause for celebration among those searching for the little buggers - since low-mass stars are much more common than high-mass stars, this means more (and smaller) planets are waiting to be found.

Wednesday, May 14, 2008

New astronomy education websites

Both Microsoft and Google have released astronomy exploration projects to allow students and enthusiasts to explore the heavens, according to an article in the New York Times. Google Sky and Microsoft's new entry, WorldWide Telescope, promise to bring astronomy to the myspace generation, and I hope they succeed at that. However, I was more interested in a short line in the article that mentions a professional version of the Microsoft product is being developed in conjunction with the Harvard Smithsonian Center for Astrophysics.

(I am disappointed that the Google team, with a stated desire to organize all the world's information, isn't the impetus for the professional product.)

When I arrived at graduate school, my first project, in 2003, was to analyze observations the group had taken in 1998 and 1999. No one had gotten around to looking at the images, because with the advent of CCD's, it is incredibly easy to collect data, and much more difficult to find people and time to analyze it. Additionally, there are several all sky surveys that are collecting massive amounts of data for one or a few particular reasons (such as finding planets), and the data could be used for so many more explorations. However, all the data needs to be reduced and refined to a common level of usable information. These projects at Microsoft and Google are hopefully the first step towards bringing large disparate data sets together for consistent usage. Wouldn't it be fantastic to plug in an area of the sky and see at a glance all the digitized data available from the last few years and then analyze that imagery over time using the different data sets? Telescope time wouldn't just be used by the group requesting the time, but anyone who finds a use for the data. New discoveries could be pulled from old datasets all the time, and new telescope time could be more efficiently allocated only on those areas that haven't received any attention.

There are certainly a lot of scientific and technical challenges standing in the way of a project like this. But I think Google has some pretty smart guys. I hope they can take a crack at it.

By the way, apologies for the absence of posts, while I was moving to a new apartment

Sunday, April 27, 2008

Chinese space dominance?

There is an interesting bit on CNN, nominally categorized as election news, which considers US space resources for the next president, and promotes the idea that China will surpass US space dominance by the end of the next president's next term. I am inclined to consider this fear-mongering, or at the very least fishing for a story, and the inclusion of a quote by Bob Zubrin sort of solidifies it for me.

I am a pretty big fan of Zubrin, but I think he has a tendency to exaggerate in order to get people to listen to him (perhaps that is a necessity when discussing the space program). Speaking of the Chinese, Zubrin had this to say:
"And we're standing still. If we continue to stand still, by the middle of the next decade, their space program will be superior to ours and they'll be moving on to the moon and Mars, while we're ... looking back on our former greatness," he said.

That is a gross exaggeration, because up to now, the Chinese have basically been repurposing Russian space technology. I don't think the Chinese have shown definitively they can create their own technology, and they would need to do that in order to put people on the Moon or Mars.

I support the space program, and I want it to succeed compared to the programs of the Russians and the Chinese, but I don't think screaming about the sky falling is the way to do it. At least I hope it isn't.

Friday, April 25, 2008

I'm surprised Russia does as well as it does

There were some complications recently with the Soyuz capsule which returned the International Space Station crew to Earth. The capsule made a steeper-than-normal descent and missed its target landing zone by 260 miles, and though some systems were damaged, the passengers are fine. I've always heard before that though the Russians seemed to compete with the US on the space race, they were never able to develop the precision technology that would be required to land a man on the Moon. I don't know if I believe that, but 260 miles does seem like a pretty big error.

However, I think what is more remarkable is the annual budget of the Russian Federal Space Agency, and their remarkable accomplishments with basically no funding. The annual budget of NASA is around $16 billion, with around $500 million spent on each shuttle launch. Compare that to the annual budget of the Russian space agency, which is around $900 million. With those kind of numbers, I am amazed that Russia is the space force it is.

Additionally, it makes a bit more sense why Russia would allow space tourists to pay $20 million for a ride up to the space station. With one passenger, they can increase their budget by 2%. You think NASA would let someone come along for the ride for an extra 2%, or $300 million? I hope they would.

Sunday, April 20, 2008

Yuri's Night

This post is a little late for this year, but in case you're looking for things to put on your calendar for 2009...

Yuri's Night is a fun celebration every year on April 12th, marking the anniversary of Yuri's Gagarin's flight as well as the first space shuttle flight. This year, there were about 200 parties around the world in something like 50 different countries. We had a party at NASA Goddard that included a chance to see Science on a Sphere, a really cool way to show some of the awesome science that we do at Goddard.

For more details on the Goddard party, check out this link:

Also, I was interviewed by a TV station in Baltimore on April 10th about the party, so if you'd like to check that out, take a look:

Wednesday, April 16, 2008

German boy schools NASA, suggests asteroid may hit the Earth

This is an interesting article, especially considering our recent post on asteroids impacting the earth. A German school boy considered the probability of the Apophis asteroid hitting the Earth in 2036, when it will be coming closest to the Earth, as published previously by NASA. NASA said that the asteroid would pass near the Earth, but probably not hit us. NASA ultimately calculated that there was a 1 in 45,000 chance that the asteroid would hit us. However the school boy, Nico Marquardt, calculated also the possibility that the asteroid would hit a satellite in an earlier close encounter with the earth in 2029. The chance of the asteroid hitting a satellite (and the resultant change in velocity), increased the probability of an earth impact to 1 in 450 in 2036. What is even better than his results is the fact that the kid is 13 years old, and he was doing this work for a science fair project. How fantastic. I think his future is bright (um, unless the earth is destroyed with a massive asteroid he discovers.)

Friday, April 11, 2008

Obama Wants to Kill Space Exploration

It's official (check out this article for a good commentary) -- and sad. It doesn't stop me from supporting him for President (which I do), and i certainly agree that the current state of the space program isn't very inspiring, but putting space exploration completely on hold until "the mission is clearer" makes absolutely no sense -- he's basically arguing that we should stop working on the problem because we don't have a good solution yet. That makes no sense. Space and space exploration is one of the hottest topics in science today, and relegating it to the "not inspiring" category -- by someone who says he's all about inspiration -- seems completely myopic. If he wants inspiration and change in the status quo, he should see NASA and the whole space exploration effort as the perfect opportunity for re-invigoration, not cancellation.

And pitting it against pre-K education programs?? Of course it's going to lose -- another victim of a standard Washington budgeting ploy, by someone who says he wants to change the system. If he compared the budget of the space program with other long-term exploration science goals (things like particle colliders, deep sea exploration, etc.), and then justified his position based on a clear ranking of each of these goals and the overall budget plan for exploration science in general, I would at least respect his decision. Instead, by weaseling out he looks like he's trying to sweep it under the rug like any other politician. And that's just sad.

Thursday, April 10, 2008

UK Astronomy Under Threat

My first project as a Ph.D. candidate was to analyze NGC 6940, a galactic cluster, for transit events. The cluster was observed from the Isaac Newton Group (ING) of telescopes at La Palma in the Canary Islands. It is a popular destination for British astronomers, because it was fairly easily accessible and the telescopes are British-funded.

Now, it seems that ING and several other UK astronomy projects are threatened by funding cuts. It is a real shame, but I think American astronomers should follow this closely. However tight US scientists think their budgets are, it can be more difficult elsewhere. Brits don't even have the anti-science sentiment that can be found around the US. Instead, this reduction in resources is simply a budget crunch. The research councils, including the STFC, which funds astronomy, are funded by the UK government, and there simply isn't enough money to go around.

In the US, students have rightly complained that higher education costs have increased 5-8% annually, but when public funds don't keep pace with education and research, tuition costs (and to a much smaller extent, private fundraising) have to fill the gap. The UK education system has only recently allowed tuition fees, and those aren't even allowed in some places, so instead you have the situation where good science is shuttered, and projects are canceled.

What a shame.

Monday, April 7, 2008

Baby planet found

A colleague at St. Andrews announced this past week that she had observed a protoplanetary bulge around HL Tau. I previously wrote on the difficulties of figuring out how planets formed, because basically it seems that it takes such a relatively short time to form planets, and because forming systems don't necessarily lend themselves to easy observation.

I might argue that it is difficult to say that this is a planet instead of a brown dwarf, but this is pretty new territory. We can see it forming in the disk of a star (which is traditionally defined a planet), but it seems to be a bit above the deuterium burning limit of 13 Jupiter masses.

In any case, kudos to Jane and her team for pushing the limits knowledge of exoplanets.

Sunday, April 6, 2008

Asteroids will kill us all!

Well, not really, I suppose. A new article in the journal Icarus describes how we might attempt to deflect near earth asteroids if they were on a collision course with Earth (purchase required).

There is a pretty good write up of the article at Ars Technica, which is free-er to read than the actual journal article (that is to say, it is free).

It is comforting to report that the basic gist of the article is that it is possible to save ourselves from a collision if we were watching the asteroids sufficiently far in advance to be able to deflect them decades before their actual collision with the Earth. At that point, we could apply a relatively small amount of force in order to knock the asteroid off its intercept course (that sounds Star Trekkie).

This brings up a good point, brought up by a friend a few years ago, when he attended a lecture about the statistics of destruction, and found that chances of dying by asteroid impact (1 in 20K) were higher than dying by tornados (1 in 60K). Since my home town just had horrible twisters late last week and my family spent the night in the hallway, this is especially timely for me. You are probably thinking, "how could dying by asteroid impact be common? I've never met anyone who's died by asteroid, but I know people die in tornadoes."

Well, it comes down to statistics, and the amount of destruction that an asteroid can inflict. Let's take easy numbers, and take a look. We know from geological evidence about how often large meteors hit the earth. There was a meteor in Russia in 1908 that knocked trees down in an 800 square mile area. Let's assume that one of these events happens every 100 years and can kill 50% of the inhabitants in a city. Let's also assume that for the next 1000 years cities will average about 10% of the land coverage in the world, and that over the next 1000 years the average size of a city will be 10 million people. So, over the next millennium, 10 large-ish meteors will hit the Earth, 70% will fall in the ocean, and 30% will hit the land. Of the 30% that hit the land, 3% will hit cities (because cities cover 10% of land). The 3% meteors will kill 50% of 10 million, so 150K on average over the 1000 years. This contrasts the 50 people per year who are killed by tornadoes, which would only mean 50K deaths from tornadoes over 1000 years. All of this should make asteroids scarier than tornadoes, but in this situation we don't really fear the unknown asteroids, we fear the tornadoes.

My numbers of course are all rough estimations, but it shows how important the work is to attempt to safeguard humanity against meteors. The tens of meter sized objects (like in Russia), are not really all that concerning (unless you are caught underneath it), but the hundreds of meter sized objects are. We might not get a second chance after something like that.

Tuesday, April 1, 2008

Virgin and Google having a little fun

Google and Virgin today announced product Virgle, a manned mission to Mars complete with an application, website, and video call to action.

Now, of course they are having a bit of fun, but what a great way to have a laugh. They've put together a full website that allows all of us who hope and dream to pretend, for just a bit, that perhaps we will get to Mars in our lifetime, and that perhaps, space exploration can become the purview of citizen scientists, instead of a few government employees.

Reading through their material certainly puts a smile on my face. Right now I am trying to think of what to put in my application video...

Monday, March 31, 2008

A little bit of knowledge...or 21st century luddites

So, there is an article in the New York Times that discusses two men filing a lawsuit to stop CERN from operating the Large Hadron Collider:

Walter L. Wagner and Luis Sancho contend that scientists at the European Center for Nuclear Research, or CERN, have played down the chances that the collider could produce, among other horrors, a tiny black hole, which, they say, could eat the Earth. Or it could spit out something called a “strangelet” that would convert our planet to a shrunken dense dead lump of something called “strange matter.”

It actually worries me a little bit that this was such a popular article in the New York Times. Dennis Overbye is an excellent science writer, in my opinion, but I do worry a little bit that people who read the article won't understand the infinitesimal possibilities of what Wagner and Sancho are suggesting. Journalists in general tend to give equal weight to opposing viewpoints (and in general I suppose that is sound journalistic principle), but in science journalism, it is often disingenuous to give equal weight to say, the flat earth society against 100% of geologists who can show that the earth is spherical.

As one reads the article, however, it is very clear that Wagner and Sancho are woefully unable to make a cogent argument against the collider. Wagner "studied physics and did cosmic ray research at the University of California, Berkeley, and received a doctorate in law," while Sancho "describes himself as an author and researcher on time theory." I am not suggesting that I understand all the physics or possibilities of what could happen while operating the LHC, but I am comfortable suggesting that Wagner and Sancho certainly don't. They seem a bit like 21st century luddites, scared of the future.

My favorite line of the article is the concluding paragraph, which makes very clear what the reporter Mr. Overbye thinks of the lawsuit,
Dr. Arkani-Hamed said concerning worries about the death of the Earth or universe, “Neither has any merit.” He pointed out that because of the dice-throwing nature of quantum physics, there was some probability of almost anything happening. There is some minuscule probability, he said, “the Large Hadron Collider might make dragons that might eat us up.”

Saturday, March 22, 2008

Gamma ray burst observed from billion light years away

On 19 March the NASA Swift satellite observed a fifth magnitude gamma ray burst in the Bootes constellation. It was a remarkable discover, because the red shift of the observation suggests that the explosion originated seven billion light years away, sent at a time that the universe was only half its current age. Seven billion years ago, when this light was emitted, neither the Earth nor the Sun had been formed.

However, one of the overlooked aspects of this discovery is the swiftness (pun intended) with which the astronomical community responded to observing this gamma ray burst, which was visible with the naked eye for only about an hour before it faded. After Swift discovered the burst, it sent automated announcements to a network of world-wide telescopes, which in turn started to observe the burst. For short lived astronomical occurrences, such as gamma ray bursts or planetary microlensing, mobilizing a world wide network of telescopes means the difference between getting continuous observations versus getting eight hours broken with no observations for 16 hours.

This automated coordination gives astronomy a significant advantage in capture every possible interesting phenomenon.

Thursday, March 20, 2008

Arthur C. Clarke passes away

The long term health of scientific exploration rests squarely on inspiration. If young people are inspired by science enough to pursue a scientific career, then the brightest minds will be probing the deepest secrets of the universe, instead of chasing the biggest pile of money. The images of Hubble are definitely inspiring, but I'd say that for the last five decades the bigger contributor to scientific inspiration has been science fiction (and it isn't even funded by taxpayers!).

Arthur C. Clarke has been at the cutting edge of science fiction, blending a real understanding of science (he graduated with a physics degree from King's College London) with a fantastic creative imagination. He helped pull science fiction from the literary gutter into the main stream, inspiring both scientists and fellow science fiction writers along the way. The impact of the man on the advancement of space exploration cannot be overstated, as multiple generations grew up reading his novels.

On Tuesday, Mr. Clarke passed away in Sri Lanka, his home since 1956. He was knighted in 1998 by Queen Elizabeth II, and received too many awards to mention. His influence pushing space science forward will continue for the next century, or beyond.

Wednesday, March 19, 2008

Hubble finds methane on exoplanet; later, methane==life

Tomorrow Nature will publish an article where Mark R. Swain, Gautam Vasisht, and Giovanna Tinetti explain how they were able to tease out a discovery of methane in the atmosphere of HD 189733b using Hubble. In and of itself, the discovery is great, but what the discover portends is much more fantastic.

When I talk to people about my work in astronomy, often the subject of life on other planets comes up, and I am quick to tell them that evidence of life will be discovered on another planet in our lifetime, and probably in the next couple of decades. They are both intrigued and disappointed when I explain that we will find chemical signatures of life, and not intelligent aliens waving back at us (that, unfortunately, won't happen before my time is up on this pale blue dot.)

This discovery gets us that much closer to finding this chemical evidence of life. Methane specifically is interesting, because in an oxygen rich atmosphere, methane along with sunlight breaks down in millions of years. That might seem like a long time, but for the lifetime of planets, it is pretty small. So, when we find methane in an oxygen rich atmosphere, we know that it is being replenished at least every few million of years. One of the big, regular sources of methane on the Earth are animals and decomposing plant matter. This particular planet, HD 189733b, is a gas giant and much too hot for any type of familiar life, but if we can detect methane on this planet, we can eventually detect methane on smaller, more hospitable planets.

In an article in the New York Times on the discovery, Sara Seager, one of my Ph.D. supervisors, suggests that Hubble, though quite remarkable, wasn't built with exoplanets in mind, and that the next generation of space telescopes will add exponentially to our understanding of these extrasolar planets, and specifically Earth sized planets. She really hit the nail on the head. An entire generation of astronomers is currently searching for planets, mainly because of the possibility of finding an Earth analogue. Sure, many astronomers are searching for Hot Jupiters now, but I think all of them would admit that what really interests them is finding Earth-type planets, and specifically life on other planets. This discovery of methane brings us one step closer towards that ultimate goal of finding life.

Monday, March 17, 2008

Oh that Dextre!

I am a fan of manned space flight, I always have been, and I always will be. I am a fan not because of the science we can discover by sending people into space, but mostly because of the inspiration manned space flight (so much more than robotic missions) can provide for young and old people alike.

However, some people like to play the "it's good science" game with manned space flight. Good for them for fighting the good fight. Most of the time it comes down to biological experimentation, and I completely agree that the most beneficial science that can come from manned space flight is studying the human body and natural systems in microgravity or weightlessness.

This focus on biological systems in space is one of the reasons I thought it was pretty funny that astronauts today installed Dextre, a Canadian-built robot onto the international space station. This robot can complete some of the mundane tasks that heretofore astronauts had to complete with space walks, at great expense and danger to themselves. It is ironic, since the justification of the space station is that people are needed to do good science, that the astronauts have just replaced some of their usefulness with a Canadian robot.

Don't get me wrong, I think it was a great move, to automate everything on the space station that can be automated, so that only the most interesting questions can be addressed by the human astronauts. However, why not naturally move towards no astronauts at all, and fill the station with some Japanese built robots? Hopefully because a station full of robots won't inspire people like Kirk and Spock do.

Friday, March 14, 2008

Checking in on that Moon acreage you bought...

If you haven't seen the videos of the moon's surface coming back from the JAXA Selene / Kaguya spacecraft, check them out. We've all become slightly jaded about videos of space-scapes due to all the animations and high-quality sci-fi out there, so it's important to remember that... WE'RE FLYING OVER A REAL PLANET!!  The spacecraft is 100 km from the surface, equivalent to the highest flights by research aircraft here on Earth, and the HD videos have a resolution of 10 km.  The movies beautifully show the exquisite detail of the crater structures and the drastic changes in surface topography; I highly suggest one of the clips flying over the terminator (V-044-0067 for example) where the shadows give the most contrast.

As pointed out in a nice BBC article, one of the interesting astrobiological questions for lunar exploration concerns the possible presence of water in the shadowed regions of large craters. The water would be left over from giant comet impacts and conserved due to the consistently cold temperatures in the shadows (temps on the Moon are ~ 100 degrees C in the sun and -100 degrees C in the shade). While it wouldn't necessarily be worth much on Earth (how much would you pay to drink a glass of Moon water?), water would be an incredibly valuable resource for building a sustainable human presence. Additionally, analyzing the chemical properties (such as the amount of deuterium, a heavier isotope of standard H2O) of pristine water deposits could tell us a lot about where Earth's water came from - and whether Earth-like planets around other stars would have a similar amount of water as our home planet.

Thursday, March 13, 2008

Growing Planets

One of the big problems in planetary formation is getting rocks to stick together. The basic idea is that the swirling gases and particles going around a star eventually make their way to being planets. We basically understand how small particles start to stick together to make bigger particles, and we can certainly figure out how little planets coalesce in order to make big planets, but somewhere in between particles and small planets we get a little hazy.

Our understanding is not helped all that much by a dearth of observations for this "in-between" stage of rocks going around a star, because little rocks don't reflect too much of the stellar light. Additionally, this "in-between" stage is fairly short-lived, which already puts at a disadvantage to observing.

Fortunately, a group led by William Herbst just announced in Nature today evidence of a 3 million year old star with sand-sized grains around it. This helps push forward the understanding of planet formation, which should also give us information on the abundance of planets, and what stellar systems are the best candidates for looking for planets. A little bit more observational data never hurt planet formation theorists (well, it hurts, but only at first.)