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+--- Thread: Asteroids came from minor planets + Galactic tide coming our way (/thread-5664.html)
Asteroids came from minor planets + Galactic tide coming our way - C C - Jul 4, 2018
Study reveals secret origins of asteroids and meteorites
http://news.ufl.edu/articles/2018/06/study-reveals-secret-origins-of-asteroids-and-meteorites.php
EXCERPT: The study appearing online today in *Nature Astronomy* found at least 85 percent of 200,000 asteroids in the inner asteroid belt — the main source of Earth’s meteorites — originate from five or six ancient minor planets. The other 15 percent may also trace their origins to the same group of primordial bodies, said Stanley Dermott, lead author and a theoretical astronomer at the University of Florida...
VIDEO: https://youtu.be/LrY4zFxn2FI
The galactic tide coming our way
https://cosmosmagazine.com/space/the-galactic-tide-coming-our-way
EXCERPT: [...] In galaxy collisions, tidal forces can create long streamers of stars stretching out across the cosmos. When small galaxies fall into larger ones (which may one day be the fate of our Magellanic clouds), the stellar debris creates thin faint arcs, tracing their final orbit. When large galaxies come together, these streams can be flung out in tails thousands of light-years long.
The collisions can be dramatic in other ways as well, as galactic gas coming together can cause a burst of new star formation and feed central black holes. Over time the cores of the galaxies spiral together and the stars wash back and forth, blurring out the original structures to coalesce into an elliptical blob. We see galaxy mergers all over the sky, and especially in clusters of galaxies, where immense masses gather together into one structure. We also know, however, that mergers happen less often than they used to.
As the universe expands, the distance between galaxies not already tied together by gravity is getting larger, so they bump into each other less often. Over time, that will mean fewer stars, and a darker, lonelier cosmos. Meanwhile, we have Andromeda. When it hits, in about four billion years, it will be the biggest light show our galaxy has ever seen....
MORE: https://cosmosmagazine.com/space/the-galactic-tide-coming-our-way