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Comment by legrande | Hacker News Reader

> We believe the change was sparked by a few small precursor proteins that performed key steps in an ancient metabolic reaction

Anyone believe the Panspermia[0] theory?

> Panspermia proposes that organisms such as bacteria, complete with their DNA, could be transported by means such as comets through space to planets including Earth.

For all we know there could have been an Earth-like planet that had life in the early solar system, and they got destroyed by large impacts, and some of that life rained down on Earth (in a simple form).

There is also the theory that life propagated from distant star systems that harbored life (or still do) and had enough time to spread to Earth.

[0] https://en.wikipedia.org/wiki/Panspermia

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That doesn't really change the question if how life originated though, does it? It only proposes another place of origin, not a method of origin.

Yes indeed. But maybe the conditions for life to form are so exotic, that they are not to be found on earth?

Why would we believe that, though? Why bother with the extra layer of indirection, through an environment we know even less about?

Then there's the fact that life appeared on earth almost as soon as it was possible for it to exist. Either it was easy and formed really quickly on Earth, or space is/was so full of it that earth got contaminated almost immediately... which still implies life is common and easy. Panspermia just doesn't help.

"Panspermia just doesn't help."

It helps exploring other options, since we are still unable to create artificial life. No one is saying to stop those experiments. But maybe they cannot succed, in the same way the alchimists could not create gold in the middle ages - because some fundamental understanding or ingredient is missing. (today we can create gold, but it is not worth it with our current technology)

"Either it was easy and formed really quickly on Earth, or space is/was so full of it that earth got contaminated almost immediately"

Or it was just random chance, that a "contaminated" comet hit earth at the right time, or an alien vessel passed by and planted life seeds. We simply don't know. So we cannot rule those options out at this moment. And "almost immediately" is still in the timespan of millions of years, so plenty of time for many asteroids to hit the earth and possibly bring life.

Isn't Panspermia kind of irrelevant to answer the actual question of how life started? It's just passing the buck on to another planet.

The important part to the question is not about where, but how.

Kind of, but wouldn’t that free us up to use even more exotic parameters in our simulations? Maybe there are seed conditions that simply aren’t present on Earth.

My thinking with panspermia at least is the building blocks may be relatively common but planet earth is a unique environment for harboring life. Kind of like why we define a “Goldilocks zone” to look for et life

> For all we know there could have been an Earth-like planet that had life in the early solar system

“For all we know” isn’t that convincing of an argument given that we know so little about life’s origin.

"For all we know" is an expression that conveys a lack of knowledge/certainty, so they're using the phrase in a way that makes perfect sense.

I think this idea would be more credible if we had evidence that the earliest organisms were quite complex, with sophisticated metabolic pathways. That would be highly unlikely to evolve in a single step. As it is, it seems like early life on Earth developed from extremely simple roots. That doesn't exclude panspermia, but it means IMHO we have no compelling evidence for it and that even if it's true the organism that seeded Earth was probably very primitive.

I've always imagined this as plausible. Confronted with the infinite, it seems not only probable, but possible.

I would imagine us doing it ourselves in the future.

We might have already done it in an interplanetary way with mars.

EDIT: reading the wikipedia entry, I found this funny:

... fragment of the Orgueil meteorite ... Despite great initial excitement, the seed was found to be that of a European Juncaceae or Rush plant that had been glued into the fragment and camouflaged using coal dust. The outer "fusion layer" was in fact glue.

Panspermia isn't very good against the Fermi paradox. It makes life (and the signs of it) too abundant.

Panspermia is a great idea and we should be initiating it by sending the hardiest DNA organisms everywhere!

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