51–60 of 279 posts
https://www.bnl.gov/newsroom/news.php?a=111648
I wonder how this ties in with the submitted link about Theia. And it will be interesting if we ever get similar trapped water discovered in martian rock.
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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…
Do other galaxies matter here? A civilization would need to be incredibly powerful to be detectable from another galaxy.
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 galaxy" on significantly less than the timescale of light crossing a spiral galaxy's disk.
(I'm not saying the article is wrong, just trying to understand.)
Imagine this sci-fi plot twist: Aliens make live habitable by hitting proto-Earth with a planet, so life can sprout there. They calibrated it such a way that angular size of Moon is the same as of Sun.
So the angular size has matched the Sun only for 450 million years.
In 50 million years it's angular size will be smaller and total solar eclipses will be impossible.
Note: Due to the Moon's orbit, the whole story is more complicated.
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Do other galaxies matter here? A civilization would need to be incredibly powerful to be detectable from another galaxy.
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…
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.
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Your assumption we need water for life to exist is in my opinion wrong. We only know Earth so assume that is what is needed for life to exist.
You’re getting a lot of negative feedback for whatever reason, but you’re absolutely right. I for one remember reading about possible silicon/methane based life, etc. Actually, here’s a whole wikipedia article on what you’re talking about. https://en.m.wikipedia.org/wiki/Hypothetical_types_of_bioche... Perhaps HN folks will lose your scent now and direct their snark there
https://en.wikipedia.org/wiki/The_Devil_in_the_Dark
https://lweb.cfa.harvard.edu/~ejchaisson/cosmic_evolution/do...
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…
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The equation itself makes no assumptions. But anyone trying to calculate something with it must. The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link: ne = the average number of planets that can potentially support life per star that has planets. fl = the fraction of planets that could support life that actually develop life at some poi…
Thanks, I read that part before I shared it. It's pretty clear to me, these are pretty well defined quantities, just hard to measure. What is unclear is perhaps the definition of life. But at no point does it assume a planet must be in the Goldilocks zone. So perhaps you want to point out those assumptions you are talking about to me, because I don't see them. Edit: the parent post has been edited substantially after…