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Here's another factor: over 4.5 billion years we really don't have a good idea of what close neighbours the Solar System has had. Stars are orbiting the Milky W
by jmyeet 3y ago
Here's another factor: over 4.5 billion years we really don't have a good idea of what close neighbours the Solar System has had. Stars are orbiting the Milky Way and I seem to remember reading not that long ago (hundreds of thousands of years) our closest neighbour wasn't Proxima Centauri but some other star that is now further away.
What other neighbours have we had? How bright have they been? How close have they been? Could they have been bright enough to melt ice? If so, would this impact the dust layer? Could they be massive enough to disrupt the "dusting"?
- trilbyglens 3y agoNone close enough to have any effects like that. If there had been any close enough to have a gravitational influence the planets orbits would be either super scrambled up, or they would have gotten yeeted off into interstellar space. "Close" in terms of stars is still super duper far apart.
- user6723 3y agoThe ancient cultures an every habitual continent astronomically identified their "gods" as Mars, Venus, and Saturn. Why did they do that?
- mock-possum 3y agoIt was an inside joke, we don’t get it anymore.
- ianburrell 3y agoWe know close stars back 4 million years, and 5 million years in future. The closest known was 0.17 at 1.2 million years ago. That is close enough to disturb Oort Cloud but not be more than bright star. I’m amazed that can go back that far with Gaia satellite data. There is a limit where the stars involved are too far away.