harbourwall
harbourwall t1_j289tuq wrote
Reply to comment by RegisterThis1 in How fast does the Milky Way spin? How far does Earth move through space in a year? by Sabre-Tooth-Monkey
And Eric Idle. It may be a bit silly, but his Galaxy Song really is a useful memory aid for a lot of the numbers being discussed here.
harbourwall t1_izuedpx wrote
harbourwall t1_irw4u2m wrote
Reply to comment by LevelPegging in The vast majority of the 150-400 billion stars in the Milky Way haven't been directly detected. Alpha Centauri is the nearest known star to Sol. What is the probability that there are nearer stars that remain undiscovered? by [deleted]
> Scholz's star
Can we tell if it has any satellites, or grabbed any out of the Oort cloud as it passed?
harbourwall t1_j52kumd wrote
Reply to comment by Slashy1Slashy1 in Given that reproduction is difficult or impossible when both animals have different numbers of chromosomes, how did so many species evolve to have so many different numbers of them? by MercurioLeCher
Inbreeding becomes less dangerous the more common it is, and people in early tribal groups were a lot more closely related than today. Genetic differences between groups increases and all it takes is a bottleneck event to make the tribe of 44s the new standard number of chromosomes. Speciation through increased diversity between many groups of genetically similar individual, followed by selective or random culling of many of those groups.
That's a viable explanation of how we ended up with 46 instead of the 48 the other great apes have.