Elizabeth Barrette (ysabetwordsmith) wrote,
Elizabeth Barrette
ysabetwordsmith
  • Mood: busy

Homelike Solar System Discovered

Here's some exciting news for those of us interested in space colonization:

Astronomers have discovered a planetary system orbiting a distant star which looks much like our own. They found two planets that were close matches for Jupiter and Saturn orbiting a star about half the size of our Sun. Martin Dominik, from St Andrews University in the UK, said the finding suggested systems like our own could be much more common than we thought.


I think they're right; technology is moving closer to being able to detect Earthlike planets elsewhere. Meanwhile, finding a solar system whose set of gas giants is similar to our own is a good way of indirectly hinting at which systems might have undetected terrestrial planets.
Tags: news, science, space exploration
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  • 10 comments
alaneer

alaneer

April 7 2008, 20:24:13 UTC 13 years ago

This is indeed exciting. I've read about the plan to use the microlensing technique and was impressed. Didn't think it would produce results so fast though.

Now all the star system needs is an earthlike planet with a large moon in the proper zone, as it already has the other prerequisites for life, the gas giants.

Too bad we can't reach it in the unforseeable future.
anamacha

anamacha

April 8 2008, 09:27:43 UTC 13 years ago

why would an Earthlike planet *require* a large moon? And why would gas giants be prerequisites for life in a system?
alaneer

alaneer

April 8 2008, 14:29:10 UTC 13 years ago

A planet's spin needs to be stable in order for life to evolve. If Earth didn't have a large moon to stabilize its axial spin, it would eventually wobble too much. That would cause severe storms and even continent slides. Life could not survive under those conditions. Earth would even tumble over, as Mars probably had in the past because it lacks the mass of large moons/moon.

Jupiter and Saturn sweep most of the debris out of the Solar system, away from the inner planets, Earth in our case. The large gasous planets are massive, with massive gravitational wells and electromagnatic forces. If we didn't have them here, or at least one of them, the Earth would have been/would be bombarded with large asteroids and cometary debris. Like the one 65 million years ago that killed the dinasours. So in order for life to evolve and thrive, we need the Jovian planets.
anamacha

anamacha

April 8 2008, 23:35:21 UTC 13 years ago

makes sense -- you might want to look at my other comment in this thread, the one I made to the Original Poster.

ysabetwordsmith

Thoughts

ysabetwordsmith

April 8 2008, 17:10:10 UTC 13 years ago

The theory is that a large moon helps stabilize a planet's orientation. Since most of the planets in this system have fairly upright orientation, I'm somewhat dubious of the claim. On the other hoof, one of the planets is pretty much lying sideways. On the third hoof, life is creative and tenacious. It does seem to benefit from a large moon, but remember, we're working with a sample of one Earthlike world. We could be an anomaly -- almost certainly are, in one aspect or another. (Everything is weird someway.) Once life establishes itself, it has a good chance of adapting even to catastrophic changes. Earth has been frozen, steamed, and smacked with space debris many times, and we're still here.

Gas giants are shrapnel traps. They help reduce the amount of space debris that smacks into planets. This is good for life. We're pretty sure this theory is sound, because we can map out how their gravitational effects manipulate the asteroids and comets. A lot of their little moons are captured debris.

For a more thorough exploration into these ideas, I recommend ...

NASA's main site:
http://www.nasa.gov/

NASA's popular science site:
http://science.nasa.gov/

Science fiction is also excellent for thought experiments. There are many stories about space oddities such as biospheres that thrive on or are indifferent to debris impact or extreme climate fluctuations. Alan Dean Foster's Icerigger is a good example of extreme fluctuations. Also notable is Hurricane Moon by Alexis Glynn Latner, which explores the need for a moon orbiting a colony planet.
anamacha

Re: Thoughts

anamacha

April 8 2008, 23:27:51 UTC 13 years ago

ah, true -- it was very early when I posted my comment, and didn't think of the "junk trap" angle of gas giants (and large moons, too; look at all the craters on our moon).

Still, our gas giants are so far away from us -- it seems unlikely that they would be able to intercept all debris flying our way. Still, there are four of them, thus increasing the chances of such an interception.

If I recall correctly, the Earthlike planet they found in the show I watched was rotationally stable -- like our Mercury, it always presented just one face to its sun. I think this would make weather and such on that planet rather interesting -- \ for an interesting SF treatment of this idea, try MJ Engh's _Wheel of the Winds_.

Anyway, moons would be required for tides and such, but I don't think those would be necessary per se to support life.

Maybe our moon keeps the Earth in a stable orientation, even though it is tilted some with respect to the plane of its orbit? Such an orientation is what gives us our seasons; it would be rather different for a planet with no such tilt.
alaneer

Re: Thoughts

alaneer

April 8 2008, 23:58:41 UTC 13 years ago

It's true that they don't fling out or capture all debris, but they do most of them. And whend the Solar system was young there were much more stuff flying around. The distance is not relevant in this case because comets come from the Oort cloud, and the asteroid belt is close to Jupiter.

As to the tides of the Moon, you're right; they're not necessary to life. The Moon is tidelocked to the Earth, shows only one face, like Mercury is tidelocked to the Sun, but it's the Moon's mass that keeps the Earth's spin from changing too much, because of its large body the Moon has a gravity of its own.
anamacha

Re: Thoughts

anamacha

April 9 2008, 00:21:01 UTC 13 years ago

makes sense, yes, except for the fact that the asteroid belt is THIS side of Jupiter -- in other words it's not really relevant to the "jupiter traps flying space stuff" theory. It wouldn't trap stuff coming this way from the asteroids because of the relative placements.

So you're suggesting that if we didn't have the Moon to stabilize the Earth's rotation, we'd eventually flip pole-for-pole? Interesting theory. Have any idea what kind of timeframe that takes place in?
alaneer

Re: Thoughts

alaneer

April 9 2008, 00:45:06 UTC 13 years ago

The asteroid belt now is pretty stable as far as a belt of debris can be stable, but it wasn't so when life was beginning on Earth. It's true that it's on this side of Jupiter, but the Jovian mass and would still fling a debris knocked out of its orbit outward. Then too, there are some Near Earth Asteroids that come this way, so it's not a foolproof system. I'm not a an astrophysicist, so I don't understand the planetary mechanics on the mathematical level, but it works. (according to the experts)

It would take a very long time for the Earth's spin to destabilize, enough so the planet would tumble, probably on the scale of hundreds of thousands years, even millions. I'm only guessing. But it would happen. Some scientists think it happened to Mars.
anamacha

anamacha

April 8 2008, 09:26:31 UTC 13 years ago

yes -- I saw something like this on a program I watched on the Science Channel. I don't remember what it was called -- something about searching for other Earths.

At any rate, I don't remember the name of that system either -- but I don't think it was OGLE-2006-BLG-109L :)

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