4 ms·
Isaac Arhur touches on this subject in one of his videos, Intergalactic Colonization [1]. Basically, the void between galaxies isn't actually that much of a vo
by cletus 8y ago
Isaac Arhur touches on this subject in one of his videos, Intergalactic Colonization [1].
Basically, the void between galaxies isn't actually that much of a void. It's just in intergalactic space stars tend to be hundreds or thousands of light years apart rather than the 5-10 (where we are in the Milky Way) or, say, in light weeks or less in the galactic center.
It's known (and he talks about) stars being ejected from galaxies. This is important because a lot of intergalactic stars have high metallicity and are likely to at least some of the time still have their planetary systems.
It is interesting to consider where these stars came from. A nearby galaxy being the obvious candidate. I wonder if the 3D velocity measurements can be precise enough to ever determine this to a high degree of likelihood. It would be cool to find some intergalactic visitors in our own galaxy.
[1]: https://www.youtube.com/watch?v=xRB7a89Jh7w https://www.youtube.com/watch?v=xRB7a89Jh7w
- valarauca1 8y agoDealing with dark matter halo's is likely non-trivial. While the science is still out, the most likely dark matter candidate is 15-50 solar mass black holes [1]. The idea of having thousands's of light years of empty space with the same approximate black hole density as the galactic disk, but without the dust, gas, or stars to see their effects is rather a horrifying barrier to exploring the halo stars. [1] This is a possibly theory. It is counter to axion theory (massive weakly interactive particles) as Axions require CPT violations we can't create experimentally, and LIGO is seeing collisions of black holes in the correct mass range, and which can't be created via stellar collapse (as they're just too big). Which lends some credibility to this mass range (also it wouldn't impact the CMB so the theory holds a fair amount of water).
- drjesusphd 8y agoHorrifying in what way? In the sense of being nearly impossible to navigate taking into account their gravitational effects? If these black holes are just as dense as in the galaxy, wouldn't that make navigating the galaxy just as difficult? The distances are longer, but that just means corrective burns have a stronger effect on the future trajectory.
- everdev 8y agoAskEthan did a great write up about this exact scenario and if planets could escape along with the star: https://medium.com/starts-with-a-bang/ask-ethan-can-stars-escape-from-the-galaxy-with-planets-intact-e8b6f4bf73ef https://medium.com/starts-with-a-bang/ask-ethan-can-stars-es...