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> We can estimate how many comets are out there with orbital mechanics models, but what about objects originating from outside the solar system? We can estimat
by avian 6y ago
> We can estimate how many comets are out there with orbital mechanics models, but what about objects originating from outside the solar system?
We can estimate the frequency and size of impacts, regardless of the origin of the impacting body, from observing craters on the Earth, moon and other planets. Those show that the "end of life" impacts are pretty rare - the conclusion that also follows from the fact that we're having this discussion here.
- willis936 6y agoThe solar system has an orbital period of 250k years. Nearby systems do not have the same orbital period. I’m not sure galaxies are considered stable to individual stellar systems.
- breck 6y ago> The solar system has an orbital period of 250k years. I thought it was 250 million years, though maybe I'm misunderstanding you. [1] [1] https://www.sciencefocus.com/space/how-long-does-it-take-the-sun-to-orbit-the-galaxy/#:~:text=We%20tend%20to%20think%20of,to%20complete%20a%20single%20orbit https://www.sciencefocus.com/space/how-long-does-it-take-the....
- willis936 6y agoMy mistake! I didn’t check, but knew the value was in the range of “too long to assume our galactic neighborhood is static or even repeating but too short to not have had potential repetitions show up in Earth geology”.
- Gravityloss 6y agoThe dinosaur killer was estimated to be 10 km diameter. Oumuamua is much smaller, maybe 0.1 to 1 kilometers long and narrow.