00:04Scientists posit that the Milky Way galaxy, the one we live in, absorbed as much as half
00:08of all of its mass from devouring other galaxies.
00:11Now our nearest galactic neighbor is doing the same, and scientists are observing the
00:15phenomenon in action.
00:17Andromeda is that nearby galaxy, situated just over 2.5 million light years away.
00:22Astronomers have now identified more than 7000 stars that have become part of that galaxy,
00:26and they say it all happened around 2 billion years ago.
00:29This was all observed with the Dark Energy Spectroscopic Instrument, or DESI, a device
00:34meant to measure the impact of dark energy on the universe's continual expansion.
00:38The researchers say the absorption of another entire galaxy was likely the cause, bringing
00:42with it thousands of stars.
00:44With the authors of the paper writing, quote,
00:46We have never before seen this so clearly in the motions of stars, nor had we seen some
00:50of the structures that result from this merger.
00:52Those structures include stellar streams, debris, galactic shells, rings, and plumes.
00:57Adding that much of the material within the inner halo of Andromeda comes from a single merger,
01:02one to two billion years ago.
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