ET extremophiles?

[Blind groper]

When we read of new planets being discovered, around other stars, a common question asked is if there is life there. A very frequent rationale used is to refer to Earthly extremophiles, which live in, what to us is, very hostile conditions. Such as deep below the surface bacteria and nematodes, bacteria in hot springs etc.

I am unconvinced. The reason for my skepticism is that we do not yet know what conditions are required for abiogenesis. It is all very well to note that some life forms can thrive as extreme salinity, acidity, pressure, temperature etc. They have had over 3 billion years to adapt to such conditions. That does not mean that a planet that has such conditions will develop life. If life, for example, needs a pool at 45 C and 2% salt, before it can develop out of non living chemistry, then it will not develop and adapt to conditions that are extreme.

My view is that, until we know the conditions which non living chemistry needs to form the first life, we cannot make judgments about life on other worlds that have conditions an Earth extremophile might thrive in.

Any other views?

[cronus]

Life has changed the atmosphere etc here on earth radically since it started. Seeking the optimum conditions for life means not overlooking life altering the terrain. I'd hazard a guess aliens would be more adapted to earth than most orthodox scientific imagination suggests?

[Calilasseia]

We've a fair idea about the chemistry of abiogenesis though, and that it works in the laboratory in conditions intended to simulate a prebiotic Earth. Moreover, there's a raft of recent papers demonstrating that the synthesis of the simplest organic compounds required for life, can take place in interstellar space within cometary ices. Additionally, some scientists are eyeing Titan as a nice, juicy target for a mission constructed to detect possible exotic life.

[Blind groper]

That may be true, Cali, but I have read at least half a dozen proposals for different ways abiogenesis may have occurred, from radioactive beaches to hot springs, to cooler pools. From salty oceans, to fresh water lakes. We just do not yet know.

Titan may, or may not be a possible source of life. Only time and exploration will tell.

[Gawdzilla Sama]

How long until we have abiogensis sussed out? I'd like to see the faces on the fundies when that happens.

[PsychoSerenity]

That may be true, Cali, but I have read at least half a dozen proposals for different ways abiogenesis may have occurred, from radioactive beaches to hot springs, to cooler pools. From salty oceans, to fresh water lakes. We just do not yet know.

Titan may, or may not be a possible source of life. Only time and exploration will tell.

Well there may be many different ways it can occur. If so, we'll probably never find out how it did occur here, but that doesn't matter.

[Blind groper]

I think we can consider it cracked when we can duplicate it in the lab. That might even happen in our own life times.

[cronus]

Maybe seeded by comets....that means the initial conditions were quite different from a planet. If life arises most often in gas clouds that puts back the odds of figuring the precise conditions and stuff necessary, doesn't it?

[Gawdzilla Sama]

I think we can consider it cracked when we can duplicate it in the lab. That might even happen in our own life times.

It has to be repeatable to be science. The table top cold fusion fiasco of the early '80s stands as a reminder of that.