What do you think about Panspermia?

The closer ecosystems are, the more probable it becomes, imo.
I'm not convinced about the universal "pan" stuff, though.

>>9118323
It makes a lot of sense to me: the initial steps of life, like getting some simple self-replicating protein are fairly unlikely, so the huge surface area of space dust helps that along, then the dust plants these proteins on Earth (or some other planet) where they then evolve into complex life. That is much more likely than proteins themselves appearing on Earth.

Panspermia merely delays the question of where life comes from. Even if it's found microscopically throughout the universe, that still doesn't doesn't tell us WHERE it comes from.

Also, f it existed throughout the universe that doesn't make sense, because Earth would have been seeded with life many times, not just once. Yet all life on Earth has DNA in common, and isn't fundamentally different from itself.

>>9118323
It's one of the most important scientific questions we'll face, imo. And one of the hardest. We can get a quick glimpse of the answer in the not so far future, though. If we happen to find life in one of Jupiter's satellites, if it's DNA based, panspermia gets a boost, otherwise it's most likely kill. If life gets different architectures in something as close together as the solar system, then it's unlikely we'll find similar life among different stars.

>>9118323
It becomes more probable as the universe ages, at least within galaxies. But it's more likely that the building blocks are produced in space and spread like that rather than from already extant life. Unless maybe it's common for advanced spacefaring species to dump their waste in space during travel.

>>9118467
What if viruses are the result of a second origin of life, hence their radical differences from cellular life?

>>9118459
>much more likely than proteins themselves appearing on Earth.
How are you assessing the likelihood?
Venus and Mars are the only two source candidates in this solar system, and unintentional interstellar travel seems VERY unlikely.
So if your proteins _did_ originate in the solar system, there's at least in 1/3 chance they started right here on Earth.
The alternatives (non-planetary origin and interstellar travel) seem a lot less likely than abiogenesis.

I don't think you're really grasping the scale of the Earth in relation to a protein molecule, and the vast potential for various proteins to form.
A protein molecule is much smaller than a normal, eukaryotic cell.
There are tens of trillions of cells in a human body.
Look how small we are compared to the Earth's surface.
Now consider the tens of millions of years between the end of the hadean eon and the earliest life.

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>>9118548
>What if viruses are the result of a second origin of life,
Viruses generally aren't considered to be alive.
This is largely because they are so dependent on other cells for reproduction.
That dependence also means they probably aren't alien to the DNA-style system of life.
pic unrelated