Saturday, February 21, 2009

Stargeek Atlantis

A science post is a good way to ease back in, yes?

Before October 1995 we didn't know there were any. We thought they were there, we figured they sort of had to be, but we didn't know. But then there was one. And then two. And three. And ten. And more. And more. It even turned out that yeah, a few that we saw as far back as 1988 and thought were, actually were. And as of this week, there are about 340 known extrasolar planets, planets orbiting stars other than the Sun.

And the more astronomers look, the better they are able to look, the more they find. In January, astronomers at UCal Santa Cruz were actually able to get information about the atmosphere of one such planet. And in February, the COROT space telescope discovered the smallest extrasolar planet yet known, one just twice the size of the Earth.

What's more, observations from NASA's Spitzer space telescope indicate that the materials making up the Earth and the other rocky planets in our solar system could be common in the universe - so rocky planets could be, too.

How common?
There could be one hundred billion Earth-like planets in our galaxy, a US conference has heard.

Dr Alan Boss of the Carnegie Institution of Science said many of these worlds could be inhabited by simple lifeforms. ...

[B]ased on the limited numbers of planets found so far, Dr Boss has estimated that each Sun-like star has on average one "Earth-like" planet.

This simple calculation means there would be huge numbers capable of supporting life.
And scientists are looking for them.
The telescope Nasa is preparing for launch next month won't reveal if there is intelligent life in the Universe, but it should at least provide concrete evidence that there are places like Earth for ET to live.
The mission is the Kepler space telescope, scheduled for launch in less than two weeks and its purpose is to look for Earth-sized and smaller planets.
Once Kepler is in orbit, it will have one primary task: pointing to a fist-sized section of the Milky Way Galaxy and keeping still so that its light-collecting electronic devices, known as CCDs, can do their job. ...

As sensitive as Kepler is, it will not be able to directly image a planet, which would require detectors capable of picking up relative changes in starlight on the order of one part per billion, as compared to Kepler's 10 to 40 parts per million.
Which means that any finds would have to be verified from ground-based telescopes so that electronic noise and other false hits can be filtered out. The advantage of Kepler is that it can monitor thousands of stars simultaneously and so be able to tell astronomers where to look.

One thing to bear in mind is that, as Dr. Boss noted, even Earth-like planets with life are likely
"to be inhabited with things which are perhaps more common to what Earth was like three or four billion years ago." That means bacterial lifeforms.
But on the other hand,
[r]ecent work at Edinburgh University tried to quantify how many intelligent civilisations might be out there. The research suggested there could be thousands of them.
G'Kar, are you out there?

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