From: Indy Kochte <kochte@s...>
Date: Wed, 15 Oct 2003 16:27:45 -0400
Subject: [semi-OT] extrasolar planets - where are the kra'vak??
Greetings, everyone Just a little blurb, I just returned from a very exciting two-day conference in Washington, D.C. (more exactly College Park for those in the area ;-) that covered the current findings and future work on extrasolar planets. Sat through 23 lectures in two days plus examined 50-odd posters on various topics in the field. I'm not going to summarize the entire conference, but I will tell you that there is a "new" class of planet out there (not yet discovered, but give them time) called "ocean planets". These would be (nominally at this time) Neptunes or Uranuses in what is known as the "habitable zone" (the zone where it is warm enough for water to be in a liquid state; inside the zone water is a gas, and outside the zone water is ice) (do I hear a call for water-based scenarios? ;-). So now there are four basic planet types: gas giants, ice planets (includes ice giants), terrestrial (rocky), and ocean. Thus far of the 120 planets known, they are pretty much all gas giants (a few terrestrials around pulsars, but that's it). But it'll only be a matter of time before the ice planets and ocean planets will be discovered. Terrestrials around sun-like stars will not be far behind. There was a little talk about habitable zones around gas giants, but it requires an extremely complicated orbital mechanics, and no one was quite willing to discuss that in detail. ;-) But no one was ruling it out, either. There are a large number of ground and space missions being either proposed or put together to continue the search. Given that I think they are overly optimistic in their capabilities and scale them down accordingly, it is likely we may be detecting terrestrial planets around other sun-like stars within 10 years. In that time frame it should be possible to start detecting certain biomarkers in these systems, and determine if life might be possible. We've already detected sodium and hydrogen on one extrasolar planet. At some point in the not too distant future we'll be able ot pick up oxygen, ozone, water (they are searching for it now), methane (most of it on Earth is biologically-generated), and nitrous oxide (which is produced by bacterias in the soil; Dave and Beth and elaborate on this ;-). Eventually we should be able to detect vegetation on other worlds (simply by the type of reflected spectra of the planet). My guess is that this won't happen, though, for another 15-20 years. :-/ Further down the road (my estimation ~50 years; sooner if you listen to some of the speakers ;-) there are being speculated two missions: Life Finder and Earth Imager. THe latter is currently considered monstrously difficult and daunting; the current estimated cost is about what the current deficit is for the U.S. Life Finder has more realistic goals in the 50 year time frame. It proposes to use from 5 to 80 8-meter mirrors scattered about an area in space roughly 100 km across. And with this they can (or should) be able to pick out Earth-like terrestrial planets *and* confirm evidence of life (whatever it is) within 3.5 (with 5 mirrors) to 15 parsecs (with 80 mirrors). That's ~11 to just shy of 50 lightyears out. So, with this techonology in the early/mid-21st century, why hasn't humanity detected the Kra'Vak homeworld already?? ;-) Mk