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Milky Way Melded With Smaller Galaxy in Long-Ago Cosmic Crash

Reuters

   The Milky Way, home to our sun and billions of other stars, merged with
   another smaller galaxy in a colossal cosmic collision roughly 10
   billion years ago, scientists said Monday, based on data from the Gaia
   space observatory.

   The union of the Milky Way and the so-called dwarf galaxy
   Gaia-Enceladus increased our galaxy's mass by about a quarter and
   triggered a period of accelerated star formation lasting about 2 to 4
   billion years, the scientists said.

   "Yes, indeed it was a pivotal moment," said astronomer Carme Gallart of
   Instituto de Astrofisica de Canarias in Spain, lead author of the
   research published in the journal Nature Astronomy.

   Galaxies of all types including the Milky Way began to form relatively
   soon after the Big Bang explosion that marked the beginning of the
   universe some 13.8 billion years ago, but were generally smaller than
   those seen today and were forming stars at a rapid rate. Subsequent
   galactic mergers were instrumental in configuring galaxies existing
   now.

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