PDA

View Full Version : Tha Drake equation??Bah humbug!!!!!



errorist
2004-Mar-25, 02:18 PM
If they find fossils or life on mars then the Drake equation is shot to pieces.

antoniseb
2004-Mar-25, 03:10 PM
Originally posted by errorist@Mar 25 2004, 02:18 PM
If they find fossils or life on mars then the Drake equation is shot to pieces.
No it isn't. I say this for two reasons:

First, life on Mars could have seeded life on Earth, If so, the likelyhood of life in other solar systems is unchanged, because we still count as only one example.

Second, and more importantly, the Drake equation is a bunch of unknowns all multiplied together. As we try to narrow the range of the unknowns, we narrow the range of the final number. If there is life on Mars, and it isn't DNA based, that increases the value of the fraction of planets capable of sustaioning life, and perhaps the fraction on which life evolves.

Fossils on Mars wouldn't shoot the equation to pieces, but it would up the currently expected value for the more pessimistic of us. [Personally, I guess there's three to five planets in the galaxy with life that can communicate to other planets].

http://www.activemind.com/Mysterious/Topic...e_equation.html (http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html)

Fraser
2004-Mar-25, 04:31 PM
As scientists are searching for life on Mars, there's a lot of support building for the theory of Panspermia, where bacteria travels in space and seeds various worlds. We know that asteroids can kick up material so that it can escape the Earth's gravity. We know that bacteria can survive in space for a long time. We know that meteors can enter the atmosphere of Earth or Mars in such a way that part of the rock stays cool all the way to the surface. Finally, there's evidence that bacteria can evolve pretty much "on the fly" when presented with a new situation that would kill it otherwise.

Over the course of billions of years, there must have been mountains of material transfered between the Earth and Mars. And if Mars was warm and wet at some point, life would have an ideal place to land.

By the time life is conclusively found to have existed on Mars, I don't think people are really going to be that surprised. It's likely our two biospheres have been linked together for billions of years, transfering material back and forth.

There's probably a cloud of bacteria in space going around our solar system that was kicked off of Earth and Mars. Some of this is probably getting blown out of our solar system, and leaving a trail of bacteria in our wake as our Sun goes around the Milky Way. We could have run into the trail of bacteria from another solar system, which would help to explain why life seems to have appeared instantaneously on Earth at the moment when conditions were possible to support it.

Even the authors of Rare Earth think that microbial life could be common in the galaxy, maybe even on every planet that has liquid water. Once you want to get larger than microbial life; however, there are many new factors that come into play. It might be that life on Earth was able to evolve into higher forms because Jupiter acted as a vacuum cleaner for comets and asteroids, or the tilt of our planet, or the tectonic plates.

It's probably time for a new Drake equation that considers some of the new factors that scientists understand are necessary for life.

Duane
2004-Mar-25, 08:07 PM
This is an interesting area of discussion. If you're interested, there is aDrake Equation Calculater (http://www.seti-inst.edu/seti/seti_science/drake_calculator.html) where you can plug in your own numbers for each of the varibles and come up with an estimate for the number of intelligent species in our galaxy or the universe.

The theory of Panspermia is interesting to me for two reasons. If the early Earth was the recipient of extra-solar baterium of some type which jump started life on the planet, there must still be an explanation of how life got started somewhere else in the first place. In my opinion, this is a 50/50 proposition at best at this time--that is, there is a 50% chance Earth was seeded and a 50% chance that life evolved here. As Fraser mentioned, if other life is found somewhere, it will be interesting to see if the DNA (assuming it uses DNA of course) is similar to DNA here.

Either way, the advent of life had to start somewhere, so research into how it arose is still very relevant.

I don't think the Drake equation needs to be revamped, the new factors simply refine some of the percentages used in the equation.

GOURDHEAD
2004-Mar-25, 10:11 PM
It might be that life on Earth was able to evolve into higher forms because Jupiter acted as a vacuum cleaner for comets and asteroids.......

I've read on several occasions that Jupiter has protected earth from comets and asteroids, but it does not seem to be intuitively obvious. My guess is that Jupiter would attract more stuff into the inner solar system than it would absorb and maybe cause it to hit the earth with greater speed than it would have otherwise. My guess is that its effect is pretty much a wash. As for multicellulars I think having a moon with as much relative mass as the earth has is more significant and is likely to have made the earth more unique in the developing of comples organisms.