Astronomy

For the first time, astronomers have created a data-driven estimate for how many black holes are in our Universe: more than anyone expected.

Our Universe appears to be expanding and cooling, having originated some 13.8 billion years ago in a hot Big Bang. However, it's plausible that what we see from inside our Universe is simply the result of being inside a black hole that formed from some parent Universe. If the black holes that form in our cosmos give birth to baby Universes, perhaps we arose from the formation of a black hole ourselves.

If you said "with the Big Bang," congratulations: that was our best answer as of ~1979. Here's what we've learned in all the time since.

cross-posted from: https://lemmy.sdf.org/post/6593278

On July 19, 1952, Palomar Observatory was undertaking a photographic survey of the night sky. Part of the project was to take multiple images of the same region of sky, to help identify things such as asteroids. At around 8:52 that evening a photographic plate captured the light of three stars clustered together. At a magnitude of 15, they were reasonably bright in the image. At 9:45 pm the same region of sky was captured again, but this time the three stars were nowhere to be seen. In less than an hour they had completely vanished.