RE: [semi-OT] extrasolar planets - where are the kra'vak??

Because they watched the video on "How not to be seen".

Michael Brown

-----Original Message-----
From:	Indy 
Sent:	Wednesday, October 15, 2003 1:28 PM
To:	GZG mailing list
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