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More fun are the couple of comments in the article. I am still not sure if it is sarcasm or an actually half-decent theory.
by rishav_sharan 6y ago
More fun are the couple of comments in the article. I am still not sure if it is sarcasm or an actually half-decent theory.
- madaxe_again 6y agoI actually kinda like that retrograde moon hypothesis - it’s heavy on inference and induction, but it largely meshes neatly with observed phenomena - although if you had had an alien biosphere come crashing into earth, you’d expect to see that in the tree of life, and afaik there isn’t a sudden injection of completely novel phyla at 540ma - just evolution of what was there before.
- rbanffy 6y agoIf an independently evolved biome were introduced, it'd be on a totally different tree, sharing very little with our own.
- ramraj07 6y agoTrue unless we assume venusivian and terrestrial life both had a common origin
- ComputerGuru 6y agoIt would be insanely improbable for independent life to have formed separately in such close proximity. The odds of that are entirely dwarfed by the far more likely panspermia scenario.
- rbanffy 6y agoIs there any evidence of a panspermia?
- ramraj07 6y agoNo more than evidence of life forming on earth which is zero. I've thought about it semi professionally for long, and my bet would be on panspermia. Heck, my bet would be that all life in our galaxy is probably from the same origin; it seems fairly easy for at least some microbes to survive on rocks for really long periods of time, and my guess would be that once one form of life takes hold in a place other competing forms would probably get fully eliminated. Thus it stands to reason that panspermia is more probable. This is supported further by how quickly life seems to have appeared on earth the moment it was habitable (followed by how it took billions of years after that to evolve in any meaningful way).
- dr_zoidberg 6y agoYeah but it also talks about "oversized moons" and then cites Titan and Triton as examples of oversized moons of Saturn and Neptune. Why is that worong? Titan is not oversized, in comparisson to Saturn. It's a normal, larger-than-Selene (Earths moon, but not that much larger really). Compared to Mercury, it is larger in radius, but less massive (about 1/3rd the mass). Now let's look a bit at Selene. It's an "oversized moon" at a bit more than 1% our planets mass. If that was the criteria for oversized moons, then Saturn would require an Earth-like planet orbiting around it to be considered to have an "oversized moon". Another thing to consider: if we're thinking 1% mass as the parameter, it would've required a far larger moon to crash (from a retrograde orbit) to change Venus's rotation from prograde to retrograde. Now on to Triton... it didn't form with Neptune. It's suspected of being a Kuiper Belt Object captured by Neptune that will eventually disintegrate from tidal forces once its retrograde orbit gets it close enough to the planet. If it had been formed 4 billion years ago with the planet, that would've already happened. All in all, I'm not a astronomer nor planetary scientist, just a software engineer who really likes astronomy and got a few math and physics class at uni. But this "twin planets with oversized moons" theory has very little substance.
- fit2rule 6y ago>sudden injection of completely novel phyla at 540ma Octopus. https://qz.com/1281064/a-controversial-study-has-a-new-spin-on-the-otherworldliness-of-the-octopus/ https://qz.com/1281064/a-controversial-study-has-a-new-spin-...
- baxtr 6y agoWhat the heck does the reference to Velikovsky mean?
- lopuhin 6y agoCheck out https://en.wikipedia.org/wiki/Immanuel_Velikovsky#Ideas https://en.wikipedia.org/wiki/Immanuel_Velikovsky#Ideas