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Your tea leaves are sound. I think this is why those of us interested in this are very much hanging out for results from our explorations of Mars. It's pretty
by infectoid 7y ago
Your tea leaves are sound.
I think this is why those of us interested in this are very much hanging out for results from our explorations of Mars. It's pretty much our only opportunity to see if life emerged twice in the same planetary system under similar conditions.
What are the chances?
On the positive side Mars had pretty much all the ingredients for life (chemically) and had a long enough period for at least something intersting to develop. On the negative side, the environment was still different to ours (gravity, climate, whether, etc).
We still aren't clear on what conditions need to met for like to get going. This is why both positive or negative results on Mars are exciting.
My favourite theory is that life actually takes ages to get started so much so that it started on Mars and finished on Earth (from Mars being impacted and debris making it to Earth). Kind of like a passing of the torch.
Mars: "Crap. I'm dying. Hey Earth, can you take this thing I've been working on?"
Earth: "Yep. No worries. I got this. Will try to send some back in a few billions years. Take care."
- opportune 7y ago>It's pretty much our only opportunity to see if life emerged twice in the same planetary system under similar conditions. Well there's also Titan, Enceladus, and Europa right? Titan is by far the most exotic but it could serve as an example of what happens when life evolves under a radically different environment. It has some complex organic molecules there and a very interesting/varied geology and topology. Enceladus and Europa could exhibit very similar conditions to those of the deep sea on Earth as well, which could very well be where life originated. Also at one point even Earth could have became a "snowball" planet and still able to sustain life: https://en.wikipedia.org/wiki/Snowball_Earth https://en.wikipedia.org/wiki/Snowball_Earth
- codesushi42 7y ago>It's pretty much our only opportunity to see if life emerged twice in the same planetary system under similar conditions. You mean carbon based life. Methane based life may be a possibility, and you wouldn't have found it on Mars. You might find it on Titan.
- dredmorbius 7y agoMethane is an organic (carbon-chain) molecule: CH4. Titan would have a low-temperature carbon-based chemistry, but it would remain carbon-based if focused on methane. Alternative hypothetical biochemistries usually focus on silicon.
- codesushi42 7y agoTrue. But a methane based lifeform would be radically different than the carbon based lifeforms found on Earth, and would have emerged separately.
- dredmorbius 7y agoOddly, that wasn't your claim.
- codesushi42 7y agoIt was. Read the OP's claims about Mars. Mars alone does not provide the answer about whether or not life evolved independently in our solar system.
- hdfbdtbcdg 7y agoCan you elaborate?
- codesushi42 7y agoThey would not have cell membranes with phospholipids for one thing.
- hdfbdtbcdg 7y agoWhy not? Methane is a hydrocarbon. We are made of hydrocarbons. I just can't understand what the chemical difference is. Are these differences because of oxygen? I.e. life forms of C+H vs lifeforms of C+H+O?
- aiyodev 7y agoUnfortunately, we cannot be certain life on other planets in our solar system did not originate on our own. It has been determined that meteor that killed the dinosaurs possibly seeded planets and mas far out as Saturn with microbes.
- onlyrealcuzzo 7y agoWasn't Venus at one time more Earth like than Mars? Why is Mars the only chance?
- satyenr 7y agoBecause Venus’ atmosphere is full of Sulphuric Acid and various greenhouse gases which wouldn’t allow life as we know it to exist.
- drran 7y agoOur atmosphere is full of Oxygen, which is very poisonous gas, which killed 99% of live organisms on Earth. See https://en.wikipedia.org/wiki/Great_Oxidation_Event https://en.wikipedia.org/wiki/Great_Oxidation_Event Life adapts.
- dredmorbius 7y agoThere's some speculation that Venus may have been far more earthlike for some, possibly much, of its history. Similarly, Earth wasn't particularly earthlike, in contemporary terms, for much of its history -- sometimes far hotter, frequently far colder.