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I've tried reading the paper, which is obviously less hand wavy than this mess of a blog post but pretty tough going for a layman. I still don't see how they conclude that the water arrived all at once instead of in a bunch of comets... https://www.science.org/doi/10.1126/sciadv.adw1280
Absolute garbage. The Earth has a nearly perfect circular orbit. Any collision with another planet would have pushed it off its orbit and caused it to at the very least created a more elliptical orbit that likely would have made the swings in temperature more deadly for life on Earth. This entire article is science fiction.
This makes some sense actually. Does anyone have a counterargument to this?
It's also ignoring the fact that we likely did have additional planets, but after interactions with other planets with nearby orbits, they would have been either ejected out of the solar system entirely, caused to collide, or herded into more circular (non-overlapping) orbits.
This is why Pluto is not a planet.
This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…
The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. e.g. Say chance of a random planet ever being hit by a water-carrying comet is one in a billion, then with 100B - 1T planets in the milky way it'd happen here 100-1000 times. If chances are only one in a trillion, and we're the one in the milky way, then there are still another…
But numbers can go arbitrarily low.
Absolute garbage. The Earth has a nearly perfect circular orbit. Any collision with another planet would have pushed it off its orbit and caused it to at the very least created a more elliptical orbit that likely would have made the swings in temperature more deadly for life on Earth. This entire article is science fiction.
How can it be science fiction if most scientists currently believe this?
I've tried reading the paper, which is obviously less hand wavy than this mess of a blog post but pretty tough going for a layman. I still don't see how they conclude that the water arrived all at once instead of in a bunch of comets... https://www.science.org/doi/10.1126/sciadv.adw1280
All at once is what explains the isotopic homogeneity (e.g. in oxygen) between the earth and the moon
All life on Earth is illegal immigrants from another planet.
Earlier quoted context omitted.
The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. e.g. Say chance of a random planet ever being hit by a water-carrying comet is one in a billion, then with 100B - 1T planets in the milky way it'd happen here 100-1000 times. If chances are only one in a trillion, and we're the one in the milky way, then there are still another…
> The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. But numbers can go arbitrarily low.
We had a good start. A Jupiter to clear the debris, a Theia impact to create tides and contribute to tectonics, a magnetic core, a shielded atmosphere. We had water delivered to us. Maybe even panspermia.
Maybe cell walls and mitochondria are hard. Maybe multicellular is hard. Maybe life on land is hard. Building lungs, rebuilding eyes, having actual energetic gasses on land...
Maybe life is easy, but intelligence is hard. Maybe civilization is hard.
Maybe technology development can only happen on dry land, because aqueous chemistry is hard in water. Sorry mollusks and cetaceans: you'll probably never be able to do chemistry or materials science.
Maybe you need water and carbon and other chemistries aren't robust enough.
Maybe you need lots of fossil fuel deposits to develop industry. And that requires growth without bacteria and decomposers for millions of years, implying a certain order to evolution.
Maybe you need a certain sized gravity well to escape.
Maybe surviving the great filter is hard and still ahead of us. Maybe every species can build tech where a kid in their garage can extinct the entire species by 3d printing grey goo.
There's just so much we don't know about how life could happen. Let alone intelligent life. We don't even know where we're headed.
Earlier quoted context omitted.
At the moment, rapid and massive expansion seems likely with tech only just on the horizon. Enough AI and robotics for an autonomous factory may be a mirage (such mirages have (metaphorically) happened before), but it seems like it's on the horizon. Even with relatively mundane growth assumptions, that can go from "species inventing writing" to "Dyson sphere completed, is now sending out seeds to every accessible gal…
Cmon the number of hypothetical extrapolations based on no data in these statements is beyond superstition to something like delusion
But contrawise, I do have data, they're broadly categorised as "history", "biology", and "all the stuff cited by Stuart Armstrong that time".
I've tried reading the paper, which is obviously less hand wavy than this mess of a blog post but pretty tough going for a layman. I still don't see how they conclude that the water arrived all at once instead of in a bunch of comets... https://www.science.org/doi/10.1126/sciadv.adw1280
Titan, and probably Uranus and Neptune, probably have their methane etc. as a result of outgassing - initially, the volatiles are embedded in the inner rocks, but as they gravitationally differentiate and heat - and are subject to tide-like interactions with other bodies - the volatiles are released.
(The real questions are "Why does Ganymede not have an atmosphere?" and "What's up with Venus, really?")