Science Do you believe in Panspermia?

[Pinguinboy]

Panspermia:
Panspermia is the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids, and planetoids.


Well, I do believe a bit in it (no, I didn't watch too much Star Trek), because why should we be the only (unique) lifeform?

 

[Urwumpe]

No. Aside of a lack of evidence, there is a logical gap inside it: if life did come from space, how did it evolve in first place? Somewhere it must have started - without Panspermia.

And if it started somewhere without Panspermia, why can't this have started right here?

 

[Sky Captain]

I think it is possible, after all it is proved in experiments that bacteria can survive in space and also survive g forces involved in meteorite collisions.

 

[Urwumpe]

I think it is possible, after all it is proved in experiments that bacteria can survive in space and also survive g forces involved in meteorite collisions.

But can they also be inside meteoroids?

 

[Wishbone]

Andromeda Strain was a great book (haven't seen the movie).

 

[SiberianTiger]

It's a matter of scientific theory and not one of a belief.

And proving the theory is easy: Earth must have been a "biologically dirty" planet for quite a while. Go find a life in Solar System, prove its connection to Earth life, and panspermia theory if effectively proven.

 

[Urwumpe]

Or find an meteoroid that is contaminated with those chemicals that directly responsible for life to form. Must not be bacteria. But bacteria would be much better.

 

[T.Neo]

I think it is possible for biological material to be transferred between planets in the same star system. We already know that rock-swapping occurs, I don't see why a bacterium couldn't hitch a ride within a rock and be ejected on a course to another planet.

But on interstellar scales... no. Bacteria can remain dormant for long periods of time, but not that long.

And as an explanation for alien life looking exactly like Earth life, or similar to it? Definitely, definitely not. The genes for evolving humans, or pelicans, or elephants, are in no bacterium. Those organisms arose via mutation and natural selection, in conditions that are unique to Earth. In fact, even if you converged exactly on 90% of the Earth's history- a feat that in itself would be practically impossible, you would likely end up with a very, very different end product than the world we live in today.

 

[Sky Captain]

But can they also be inside meteoroids?

If a rock containing bacteria gets ejected from Earth when big asteorid strikes then it would be possible for bacteria to be inside meteorid and potetially travel to some other place in solar system although given environmental conditions on other planets it is unlikely Earth life could take hold there at least on the surface.

---------- Post added at 08:42 PM ---------- Previous post was at 08:35 PM ----------

But on interstellar scales... no. Bacteria can remain dormant for long periods of time, but not that long.

What if the rock that's carrying life is size of a planet? Suppose a life bearing planet gets gravitationaly ejected from its home system and flies off in interstellar space. Even after the surface freezes a nuclear decay heat would provide conditions suitable for bacteria deep underground for very long time.

 

[Urwumpe]

If a rock containing bacteria gets ejected from Earth when big asteorid strikes then it would be possible for bacteria to be inside meteorid and potetially travel to some other place in solar system although given environmental conditions on other planets it is unlikely Earth life could take hold there at least on the surface.

I don't ask if it could potentially contain bacteria. I ask if it really does. Potentially it could also contain unicorns. Potential pizza is pizza that does not stop you from feeling hungry.

Can you understand the difference? It is not about forming an endless chain of hypothetical what-ifs, that eventually result in an infinitesimal chance for something happening. Maybe all your hypothetical reasoning is at one point actually impossible and wrong, and all meteoroids that we could catch in space contain no life at all.

 

[T.Neo]

What if the rock that's carrying life is size of a planet? Suppose a life bearing planet gets gravitationaly ejected from its home system and flies off in interstellar space. Even after the surface freezes a nuclear decay heat would provide conditions suitable for bacteria deep underground for very long time.

Perhaps, but I see the odds for capture, or close approach, of the planet to another star system to be very small.

I also doubt that life-bearing planets are ejected from systems every day... :shifty:

 

[Sky Captain]

I don't ask if it could potentially contain bacteria. I ask if it really does. Potentially it could also contain unicorns. Potential pizza is pizza that does not stop you from feeling hungry.

Can you understand the difference? It is not about forming an endless chain of hypothetical what-ifs, that eventually result in an infinitesimal chance for something happening. Maybe all your hypothetical reasoning is at one point actually impossible and wrong, and all meteoroids that we could catch in space contain no life at all.

Well yeah chances are small for everything happening just right, but it is plausible and then there is that meteorite found it Antarctica which may contain traces of Martian bacteria.

 

[jinglesassy]

Perhaps, but I see the odds for capture, or close approach, of the planet to another star system to be very small.

I also doubt that life-bearing planets are ejected from systems every day... :shifty:

Well with 400 billion stars in our galaxy and there are billions of galaxies so the probabilities of a life-bearing planet to be ejected once a week is fairly high. That is if life is able to start on other planets.

 

[Sky Captain]

Perhaps, but I see the odds for capture, or close approach, of the planet to another star system to be very small.

I also doubt that life-bearing planets are ejected from systems every day... :shifty:

Capture by another star would be very unlikely even chances that the ejected planet would make a close approach to another star are very small. most likely if it somehow got ejected it would be lost forever in interstellar space.

 

[Urwumpe]

Well yeah chances are small for everything happening just right, but it is plausible and then there is that meteorite found it Antarctica which may contain traces of Martian bacteria.

Or may not. Or contains bacteria from Earth. Or not.

I know the Martian antarctic meteorite evidence claim, but it is pretty much overinflated by public science writers, the actual science behind the meteorite is less exciting.

https://secure.wikimedia.org/wikipedia/en/wiki/ALH84001

If you read carefully, you will find that the biologic explanation proponents are actually residing on circular arguments and the scientific form of trolling: Inversion of the responsibility for evidence.

They simply say "Because it is not shown that biologic reasons are impossible, it has shown that it must be biologic and that all people who are saying different are not explaining all features of the meteorite"

Which is, in layman's terms, bollocks.

 

[jedidia]

Well, if panspermia holds up, it could at best be a suplemental way for life to spread. Even with panspermia, life had to evolve somewhere, so it can happen in other places too.

I like the concept of panspermia, simply for the reason of science fiction: Panspermia gives you organisms with the same basic proteins in a given region of space, which means that some of the plants and animals humans might encounter on other planets might actually be edible for them. The chances for this without panspermia is rather slim, which is why I generally use panspermia when I make up an SF-setting, simply for the fact that a lot of organisms on different worlds having at least some basic commonalities doesn't really make sense without it.

That doesn't mean that it actually fits reality, of course. But it's an elegant way to avoid an obvious hole in your world building.

 

[T.Neo]

Even then you can run into problems with some odd biology causing problems with consumption of alien organisms. I suppose though that a good deal of organisms on Earth are edible, though we are talking about eukaryotes. Has anyone eaten boiled bacteria?

Chirality isn't the only problem with consuming alien life- it could contain wholly different chemicals, that we've never seen before- ones that could have strange, even lethal effects on humans. Or they could have a biology dependant on arsenic or something and it would kill us outright.

Novel biochemicals as medecines... hmm... better get working on those spaceships.

 

[jedidia]

Chirality isn't the only problem with consuming alien life-

Of course it isn't, but you can at least process it to something digestable. If a lifeform is made up of completely different proteins it is effectively useless for any purpose. It's like trying to run an Atari disk on Windows...

 

[Urwumpe]

It's like trying to run an Atari disk on Windows...

The other way around works. :lol:

 

[jedidia]

No kidding?? :blink: