Where in the solar system would you like to see a sample returned from most?

[Omicron314]

Huh, I never knew this about Titan. I was going to say a subsurface sample of Europa or maybe one of Saturn (we still don't know what the upper atmosphere is composed of) but Titan seems to be a very interesting choice.

Which leads me to wonder, how many planets in the solar system have or once had life? Earth and perhaps once Mars, although one may have seeded the other's. Europa is a big possibility; its subsurface ocean is likely full of nutrients. Enceladus also has liquid water: perhaps it has the same situation as Europa. Maybe even microbial life floating in the atmosphere of Venus or creatures residing in the skies of the gas giants, like in 2010: Odyssey Two. And now there is a prospect for life on Titan, offering a biochemistry utterly unlike our own. Although personally, I'd be happy if just one or two of these were confirmed.

[Kryten]

They would many of the ice blocks would be sized, could bacteria survive being frozen for millions of years?

Very doubtful. DNA (or RNA or PNA, or any other theoretical precursor) will chemically break down over long periods of time. Even without taking the heightened radiation environment into account, the upper limit for a viable genome is probably in the region of tens of thousands of years, the record being thirty-thousand.

[magnemoe]

Very doubtful. DNA (or RNA or PNA, or any other theoretical precursor) will chemically break down over long periods of time. Even without taking the heightened radiation environment into account, the upper limit for a viable genome is probably in the region of tens of thousands of years, the record being thirty-thousand.

The thought about an larger ice block was that the bulk would give protection about radiation. Regarding DNA breakdown you are probably right, only benefit is that this would be an very cold and it would slow down chemical processes a lot however many millions years would stretch it.

[Idobox]

On Earth, everywhere we find liquid water, we find life. As a result, we think liquid water is a very good indicator of possible life.

Finding life anywhere, even if it has a common ancestor with Earth's, would be gigantic news, and would mean space agencies would get tons of money to send probes to other candidates.

Europa has the closest environement to Earth, and whatever we find there will be very interresting. If there is liquid water but no life, Earth's cousins or separate life will teach us a lot.

The imbalance in Titan's atmosphere an be explained without life, you just need a catalyst. Sending our one probe there and coming back with some boring non biological life while not knowing what happens in Europa would feel like a waste.

[K^2]

Very doubtful. DNA (or RNA or PNA, or any other theoretical precursor) will chemically break down over long periods of time. Even without taking the heightened radiation environment into account, the upper limit for a viable genome is probably in the region of tens of thousands of years, the record being thirty-thousand.

Bacteria are a bit more resilient to RNA breakdown, some more than others. While they tend to have the main RNA loop, many also utilize plasmids which do provide some redundancy. Fragments of main RNA loop can also become plasmids, and plasmids from one damaged cell can be absorbed into another under right circumstances. Some of these processes are assisted by viruses which can hijack RNA sequences and transfer them to other bacteria.

In other words, while bacteria may be beat up pretty bad by radiation and other environmental factors to the point of not really being functional in the environment they are used to, if they end up in an environment rich with the kinds of organic compounds they need and without any predators or competition, they might be able to recover. So if you have a planet with primordial soup primed to bear life, an asteroid from another world carrying remnants of colonies of bacteria might be just the thing to jump-start the process.

But what it really comes down to is that we don't know just how long it would take for life to start spontaneously given the right environment on large enough scale. Nor do we know what that environment has to be, or how large of an area has to be just right. So we don't know how unique such conditions are, and we have no idea how common this is in the universe. Panspermia provides an out even if conditions are very specific and times required are statistically very long. If you can get some barely functional RNA from one planet to another, then the requirements for the environment are fairly straightforward and planets with such an environment should be relatively common. And since the bacteria don't have to be delivered in good, working condition, the time that a rock can spend in space between worlds is much, much longer.

[Moar Boosters]

Venus.

Not much chance of finding life there. Just for the technical achievement of us building something that can visit, survive, and escape from a place more hostile than the bible's depiction of hell.

[SargeRho]

Europa's ocean, followed by Titan's seas, and Io's surface.

[nettcod]

Europa and Titan. Maybe Mars too.

[Drunken Hobo]

Lake Vostok, obviously. A sterile example of liquid water would be great to have. If we find life, it'd help the cause for checking Europa & Enceladus.

That or one from a deep Martian cave or lava tube. See if it's still damp down there and if anything's growing. Martian polar caps might be interesting too.

[nhnifong]

Lake Vostok! hah. That's on a certain off-limits planet if I recall...

[K^2]

Not to mention that there have already been samples retrieved from it and more are planned to be retrieved once it has a chance to settle down after being drilled into.

[Drunken Hobo]

Lake Vostok! hah. That's on a certain off-limits planet if I recall...

Yep, but if we can't do it properly at home, what's the chances we'd be able to do it elsewhere?

Not to mention that there have already been samples retrieved from it and more are planned to be retrieved once it has a chance to settle down after being drilled into.

I believe the current samples are a bit inconclusive due to the drill lubricant being mixed in with the sample. That's why I'd like to see a pure liquid water sample taken from the lake, although that'd be very difficult compared to the current method.