Weird Exoplanet Orbits Could Screw Up Alien Life 161
astroengine writes "Life is good in the Solar System. We have Jupiter to thank for that. However, if the gas giant's orbit were a little more elliptical, there's every chance that Earth would become rather uncomfortable very quickly. Researchers looking at the zoo of exoplanets orbiting distant stars have simulated several scenarios of differing exoplanet orbits and find that many don't resemble our cozy Solar System. In fact, weird exoplanet orbits may be the deciding factor as to whether extraterrestrial life can form or not."
Re:"Weird"? (Score:4, Insightful)
Complex life is another thing, of course... (or - we're frakked, because the aliens will turn out to be total badasses; due to evolving in very harsh conditions ;p )
I'm guessing where they evolved will make precious little difference, we've built tools to let us survive far more than our bodies could take. What's a little bone exoskeleton against a kevlar vest? I'm fairly sure it's only in Avatar you can fire a machine gun all over a beast's face and not have it become a bloody pulp.
Re:"Weird"? (Score:5, Insightful)
For complex life to develop, you need conditions that do regularly provide evolutionary pressure, without completely wiping out all life.
Asteroid impacts are fine and even very useful for wiping out stagnant populations (like the dinosaurs) and giving room for new species to develop into, but they shouldn't be so big that they demolish the entire planet, or occur so often that no life is possible on the surface of the planet. Jupiter plays a huge role in that.
But there are also other factors. I'm pretty sure that our big moon and the tides it generates are a big factor in creating ever changing environments that provide a lot of opportunities and evolutionary pressure for populations, and that's all caused by a devastating Mars-sized impact. But another one like that would easily wipe out all life here.
Weather, seismic activity, it all plays a role. I definitely think our planet has a good chance of being reasonably unique.
Hmmm, (Score:5, Insightful)
First, Although the smaller inner planets would be hard pressed for life the moons of the gas giants orbiting closer to the sun could harbor life. There are only 8 (Or 9) planets in our solar system but there are over 300 moons.
Add to this that scientists seem to expect that life will only evolve on rocky earth like planets so it seems like a small chance. I know that the earth is the only example of life bearing planet that we have but to expect all life in the universe to exist in the same way that we do is narrow sighted. It would not surprise me to find out that there are fish swimming in a methane ocean on a distant planet in temperatures that would kill us.
Some day I fully expect to hear "It's Life, but not as we know it" and it not be a star trek reference. Well, Ok, how about only 1/2 a star trek reference. ;)
Um yeah. (Score:5, Insightful)
Of course, the fact that we are finding these weird systems may simply be because they are the easiest to detect and all the stars with planetary systems like ours are thought to not have planets because we can't detect the planets using current methods and data.
Remember, Jupiter orbits the sun once every 12 years. So, if we were trying to detect our own solar system at 10 light years, how long would it take to detect Jupiter's effect on Sol's position?
Is it a surprise... (Score:4, Insightful)
Comment removed (Score:5, Insightful)
Re:"Weird"? (Score:1, Insightful)
Re:Is it a surprise... (Score:2, Insightful)
Re:"Weird"? (Score:5, Insightful)
True, but highly elliptical orbits pose not only the problem of harsh conditions, but of rapidly changing, oscillating conditions. This becomes a problem for the evolution of a biochemistry because every complex chemical system is only stable in a rather narrow interval. If the oscillation is large enough, there might just be no stable biochemistry possible.
Given that you need a reasonable amount of complexity to implement the basic necessities of life, in particular information storage, as well as a metabolism, I don't see much of an alternative to a carbon-based biochemistry. Carbon-based chemistry is the most versatile system, able to build a near infinite variations of molecules - this is a singular property among all the elements.
However, organic molecules tend to be not overly stable outside of a rather small temperature range. On the one hand, this is good for life, because it provides the necessary chemical reactivity and flexibility to make a living system possible. On the other hand, this severely limits possible habitats for extraterrestrial life. On the gripping hand, the conditions on Earth are not just favourable for any random biochemistry, they are favourable for the most complex class of chemical compounds possible. This does not exclude the possibility of other biochemistries adapted to other conditions, it does, however limit the set of possible conditions for life.
Re:Weird Exoplanets (Score:3, Insightful)
which raises another question... is there not a single enlisted man in the entirety of star fleet? everyone seems to be a commissioned officer.
Re:"Weird"? (Score:3, Insightful)
If it were not that I were residing on the very same planet, I would find it unthinkable that such a planet could exist. Things with low probabilities do happen, especially during billions of years and as yet uncountable floating rocks.
This is one of those cases where the Anthropic Principle is very relevant: had such a planet been impossible, there wouldn't be anyone around to consider such a planet would be unthinkable. The only universe that can be observed is one where such a planet is possible.
Re:"Weird"? (Score:4, Insightful)
Asteroid impacts are fine and even very useful for wiping out stagnant populations (like the dinosaurs) and giving room for new species to develop into
Um I'm not aware of any evidence that dinosaurs were "stagnant". They were continuously evolving to fill niches as environments changed, and exceptionally successful at doing so.
The K-T Event was obviously "useful" from the perspective of us mammals since it gave us a chance to shine and fill niches the dinosaurs previously had. It's conceivable mammals still would have out-competed dinosaurs eventually, but anything but guaranteed. So from our perspective it was a good thing.
But saying the mass extinctions of the past were "useful" from a neutral viewpoint because they got rid of "stagnant" groups like the dinosaurs sounds like an unjustified value judgment to me.
Weather, seismic activity, it all plays a role. I definitely think our planet has a good chance of being reasonably unique.
Unique, sure. Snowflakes are unique, but the differences rarely matter.
What I'm saying is, sure there will be plenty of planets with properties that make it difficult if not impossible for life to evolve. Sure our planet has a unique set of circumstances. In between, there's a wide variety of possible planets where life could hypothetically evolve, just with a different path than ours. And so far there's little evidence that this wide gray area is unpopulated (though sadly little evidence *for* these planets, but our ability to detect those planets if they exist is quite limited).