Bioastronomy 2007

By Aaron on July 16, 2007 at 12:15 pm | In Blog Posts |

I’ll be blogging from the bioastronomy 2007 conference in Puerto Rico this week.

Update #2 here

Update #1 here
Greetings from Puerto Rico!

I’ll try to keep a daily blog of activities and news from Bioastronomy 2007, one of two (usually) semi-annual meetings in the world of astrobiology. It officially runs from July 15 to July 20. However, I arrived Friday the 13th for AbGradCon, a sorta-annual conference organized by and for astrobiology graduate students only.

They had good funding so we have around 50 participants all over the world. Friday night I drove a car with people from USA, Mexico, Slovakia and Spain. We visited a bioluminescent bay about 2 hours away from the capital of San Juan. After some flailing, we found the departure point, then hit a local roadside pavillion to eat some puerto rican bread and chicken and drink sangria. It was good.

We hit the water and the bioluminescence was cool. Any movement in the water produced green-yellow light. Occasionally a fish would dart by like lightning and the wakes of the kayaks glowed like fire. Putting your hand in the water was like looking at something from that recent Nicolas Cage movie. For ecological reasons you can’t swim, but it was super tempting. The only prob was it was too crowded. You have to kayak for around 25 minutes through a narrow channel in mangrove trees to get to the lagoon. Each group has about 5 kayaks and when we passed there was mass chaos. It is pitch black so you can’t see anything except glowsticks tied to the kayaks. Imagine floating, slow speed bumper cars in the dark.

Yesterday was the 1st day of talks. Some notes:

(Note: I left my abstract list in my room so I don’t have the presenters’ name with me. During lunch break I’ll go back to my room and will update the blog with their names.)

• The theory that most of Earth’s water comes from cometary impacts is losing some of its lustre. The dueterium/hydrogen isotope ratios measured in comets differ from those found in our oceans. However, only a few bright comets have been measured so far thus this could be a selection effect (i.e. comets with these isotopes may tend to be brighter, but not representative of most fainter comets). Thus, the next step is to measure fainter comets, which requires large scopes like those on Mauna Kea. So far, the astronomers have been clouded out during each of their scheduled observing runs.
• It’s possible that high energy particles hitting the surface of Europa can lead to oxidation of the ice and thus be a source of oxygen for a subsurface ocean. Add hydrothermal vents and you get a good recipe for carbon dioxide and methane, two key biomarkers (ingredients for and products of life).
• There has been lots of recent announcements concerning methane on Mars. Most of those come from astronomers and NASA. I’ve noticed here that chemists, the experts in the field, are much more suspicious. They say we don’t understand the chemistry of Mars so we can’t claim to know the sources of any detected methane. It could be life, but it could also be meteoric impacts, radiolysis in the regolith and other processes I couldn’t understand. (I regret not taking chemistry in college.)
• Methane, hydrogen and photons mix well on Titan. And in the laboratory such mixtures always lead to creation of lots of prebiotic molecules. The problem is the lack of oxygen. It was proposed that oxygen could be temporarily released on Titan through cryovolcanism (processes similar to those on Enceladus and Triton) or meteoric impacts. These processes can melt ice on the surface and release oxygen into the atmosphere. What shocked me was the length the melted ice can exist before refreezing. A paper by O’Brien et al. (2005) estimates that an impact of a 15km object would create a melt that lasts about 100-1000 years. A 150km object impact would melt ice for 1000-10000 years, the same as a cryovolcanic dome.

There were lots of nice posters and more info. We’re hoping to setup a wiki or something to post the proceedings (talks, PDFs, etc.). If it occurs I’ll of course mention it on the home page.

These astrobiology graduate students are much better at speaking than your typical professional astronomy conference. Everyone used technology appropriately and defined their jargon. The talks were all over the place: chemistry, biology, astrophysics, etc. And this brings me to the best part of this conference. It’s interdisciplinary, so you meet people that you normally don’t get to hang out with. It keeps the discussions from getting too techie and geeky too. For example, tonight I swam with an evolutionary biologist explaining to me the core debates in the field, a Kinsey Institute researcher describing their wild experiments and two marine biologists with underwater flashlights and goggles, giving us a tour of the beach marine life. How cool is that?

That’s it for AbGradCon. The next update will cover the first day of the official conference, BioAstronomy 2007

Update #1

Hey, all. Here is a summary of some stuff I caught yesterday and today, so far. With the lead author’s name in parenthesis.

• The question of water on Mars isn’t so much whether water exists, but has it ever existed in stable environment. Current evidence points to existence of water, but does not address the issue of stability. His team has been able to define Martian history in terms of three distinct eras. The first era created the phylocilicates and likely included large bodies of stable water on Mars. This lasted about 1.5 billion years and through the early bombardment periods of the solar system. Heat was supplied by volcanic activity and bombardment. The era ended when bombardment ended and also the internal dynamo of the planet (which drives geologic activity) stopped. The next era created the sulfates and consisted of large bodies of water, but they were not stable. This was followed by the current period, which is quiet, dry and has lasted about 3.5 billion years. The important consequence of this theory is that Mars could only have been habitable during that first era. (Bibring)
• The Spirit rover has found evidence of oxidation of iron not caused by liquid surface water. Basically, the red color of Mars is due to very slow oxidation by water vapor in the atmosphere over billions of years. The “dark” areas of Mars are high altitude and just haven’t had time yet to oxidize, but will eventually also become red. Also, Spirit found evidence of early geologic activity and impact changes in the basalt, suggesting a volcanic early history of Mars. At Husband Hill, they found evidence that oxidation can happen without oxygen, which could be an energy source for life in darkness. In other words, sunlight is not needed for life so we should look into dark craters, subsurface areas, etc. (DesMarais)
• RNA and DNA are chiral structures which lead to polarization of reflected light. Thus, light reflected off of vegetation covered areas on planets with life should be polarized. This was tested using Earthshine, sunlight reflected off the Earth to the Moon and then reflected back to the Earth. (This is why under dark conditions you can make out the entire Moon even when only a crescent is lit by the Sun.) They found expected polarity (a few percent) and now are looking at how to use this to search for life on extrasolar planets (which will obviously be orders of magnitude fainter). (Woolf)
• Spectra of the entire Earth from space has not yet been consistently recorded. This surprised me as we routinely take spectra of other objects all the time. But the problem is clear: you have to be far away to do it. One group is proposing a small explorer mission to NASA to send a spacecraft out to take spectra of Earth across many phases using techniques similar to those used to image distant planets. This will give us a good calibration spectra to compare extra solar planets with. The group has received prelim funding to make a full proposal to NASA. (Atri)
• One poster said that galactic colonization by a lifeform is unlikely. It claims that there is a limit to the growth of a race in a solar system and that limit is based on the amount of energy that can created. The most efficient long term (over billions of years) fuel source is nuclear fusion of deuterium. Yet, even with that eventually a civilization will reach a point where it can only sustain itself, but it can’t grow. This makes the desire and possibility of galactic colonization unlikely. They claim there is a only a window of a few hundreds years in which a civilization will have both the means and the desire to attempt it, which certainly isn’t enough time. Then, again billions of years later, the civilization will be able to attempt it again, but probably won’t have the desire yet. Of course, this is sci-fiesque speculation, but fun thought experiments nonetheless. (Dutil)

The conference continues to be unique. The audience is very aggressive in Q/A, unlike most astronomy meetings. The last time I saw anything like this was at a GRB conference in 2000. Back then GRBs were the sexy area of astronomy (not any more, extrasolar planets are the cause celeb - for now). Yesterday a few audience members were downride rude (especially one woman from the University of Arizona). But that is only during Q/A. The side sessions, lunches, poster sessions, etc. continue to be incredibly fruitful and everyone I meet in person seems very cool and eager to share.

Update #3
Wednesday we went on field trips to some local places, including a tour of Arecibo, the largest telescope in the world. It was very hot and muggy due to a calm wind. The telescope is showing its age, but is about to get a new paint job. In fact, a couple of weeks ago some scaffolding collapsed and injured a bunch of workers painting the telescope. Since then painting, and observations, have been stopped while an investigation is conducted. Arecibo is in some major funding troubles. NSF, one of their prime funders, has announced they want to discontinue funding. However, the staff expect some funding will be eventually be found (from NSF or elsewhere), hence why the paint job was continuing. There were tons of school buses visiting with kids running all over the place. Arecibo’s E/PO activity seems to be working well. I have lots of pictures and video which I’ll post soon and maybe turn into a video podcast. I don’t have my USB cable or else I’d post them now.

I saw about half of the talks on Thursday and Friday and will summarize some interesting points below.

• One speaker summarized the current thinking on Martian microbes. On the surface, it is not likely due to UV radiation, missing organics and lack of liquid water. Just below the surface, it is not likely due to temperature (too cold), oxidation, low pressure and few, if any, organics. For a terrestrial like microbe to exist on Mars right now it would have to be: 1. Highly resistant to physical and chemical insults, a psychrophile (cold temps), an anearobe, a haliophile (likes salt), autotroph (gets carbon from air), and a hypobarophile (grows in low pressure). So far, we haven’t found any microbes on Earth that fulfill all of those conditions.
  (Nicholson)
• Placozoa are the beginning of te animal tree of life. They place an important role in the timeline of evolution for reasons such as being at the point when the first nervous systems are being formed. Biologists are learning much more about them by looking at midochondria and (soon) DNA, allowing them to look back to ancient time from the present. (Ward)
• There was supposed to be discussion to form an astrobiology society. Instead, they ran out of time and someone just stood up and spoke for 10 minutes in support of it. Later, word on the street is that such an organization may already exist, but has an unfortunate name that doesn’t sound like astrobiology (something about “searching for origins of life”, which is only one part of astrobiology). So, sadly, the political debate has already begun.
• There were neat talks about te Habitable Zone, one of my favorite topics of astrobiology. One speaker (Franck)said that out of the 86 known extrasolar planets that exist in a habitable zone around their parent star, 18 are actually situated in positions better than ours on Earth. Another speaker (Turner) mentioned that saltier seas can widen the habitable zone around a star. If a sea is as salty as the saltiest seas on Earth (Dead Sea-which really isn’t dead, etc.) then the Habitable Zone can become 32% larger.
• Debate was also heard about the existence of life and planets around red dwarf stars. The majority of stars are red dwarfs ~(75%), so the debate is important to the Drake Equation. The problem is that red dwarfs are cool, so the Habitable Zone has to be close. When a planet gets close enough to its parent star, it becomes tidally locked (same side always faces the star). So one side gets very hot while the other stays cold. The question is whether planets can redistribute the energy efficiently enough to keep at a stable and moderate temperature. No one knows.
• The Terrestrial Planet Finder (TPF) was mentioned on a TON of slides. Most speakers spoke of it as if it was a real mission. But it isn’t. NASA virtually cancelled it last year. Officially, they “zeroed out” the budget, which doesn’t cancel it but removes all funding indefinitely. As long as we have the Moon-Mars initiative, it wont’ happen. Happily, the ESA is working on Darwin and a “Super Earth Explorer” mission concept that may due much of what TPF was designed to do.
• In terms of stmospheric biomarkers, the Earth would have emitted its strongest biomarkers during the protozoic era (although some markers are still strongly emitted - such as CO². So it behooves us to look for biomarkers around younger planetary systems. Biomarkers will also be stronger in systems around the outer edge of the Habitable Zone and around red dwarfs. Also, we should be looking for antibiomarkers such as H² or CO, which are “free lunches” for life and therefore rapidly used up by life. So if they exist, then life probably doesn’t. (Meadows)
• Tinetti reported on a paper she authored which appeared in Nature last week which reports on the detection of water vapor in a hot jupiter planet. That is important because it confirms the “Kinetic” model of planetary atmospheres, which had predicted CO and H²O in hot jupiters (Liang et al. 2003, 2004). That means we have an atmospheric model we can use to predict what to expect in other planets and tune our observations to those areas.

As for the conference itself, it has continued to provide some unique moments. I heard the hotel is complaining because no one is going to the 24-hour casino they have here. Of course, we’re all scientists, we know the odds. There has also been quite a bit of in situ amore’, usually but not exclusively, among the younger crowd. This meant lots of roomate exchanges were happening, which led to lots of hijinks as people tried to check out and saddle up their debts. Hey, don’t say I ever leave out the good stuff!

I have had a terrific time here. The hotel and Puerto Rico are both nice places. But most of all, the field of astrobiology is in good hands. The multidiscplinary and international nature makes it so more fun than your typical astronomy meeting. It certainly has challenges also, as creating collaborations requires out of the box thinking. This is an area that the public loves as well. I plan to get more heavily involved as there aren’t too many educators here. The next major astrobiology meeting is in April. If funding comes through, I’ll blog from there too.