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Milky Way merger discovered 11.8 billion years ago
Astronomers have discovered evidence of an ancient galactic merger that occurred approximately 11.8 billion years ago, significantly earlier than previously documented major events in the Milky Way's history. Using data from the Hubble Space Telescope and the ESA's Gaia mission, a research team led by Davide Massari analyzed the age and chemical composition of globular clusters to trace the galaxy's evolutionary timeline.
The study, published in Nature Astronomy, identifies the swallowed dwarf galaxy as Low-energy-Kraken-Heracles (LKH). This merger occurred roughly 2 billion years after the Big Bang, pushing back the known timeline of major galactic collisions by about 1.8 billion years compared to the previously identified Gaia-Sausage-Enceladus merger.
Researchers estimate that the LKH galaxy contained approximately 500 million solar masses in stars, representing about a quarter of the Milky Way's mass at that time. This collision contributed significant amounts of stars, gas, and dark matter to the Milky Way, helping to shape its early structure and contributing to the formation of its inner core.
Entities
Bologna Observatory of Astrophysics and Space Science · Davide Massari · ESA · European Space Agency · Hubble Space Telescope · Low-energy-Kraken-Heracles · Low-energy-Kraken-Heracles · Milky Way · NASA · National Institute for Astrophysics · Nature Astronomy
Claims
What the coverage asserts, and how many sources carry each claim.
- [● 3 SOURCES] The Milky Way swallowed a dwarf galaxy approximately 11.8 billion years ago. ca.news.yahoo.com · www.phonandroid.com · www.independent.co.uk
- [● 2 SOURCES] The merger occurred roughly 2 billion years after the Big Bang. ca.news.yahoo.com · www.independent.co.uk
- [● 2 SOURCES] The LKH galaxy had a stellar mass equivalent to 500 million suns at the time of the merger. ca.news.yahoo.com · www.independent.co.uk
- [● 2 SOURCES] A collision with the Sagittarius dwarf galaxy began approximately 6 billion years ago and continues today. sea.mashable.com · mashable.com
- [● 2 SOURCES] The Gaia-Sausage-Enceladus collision, which occurred about 10 billion years ago, was previously considered the oldest major impact. sea.mashable.com · mashable.com
- [● 2 SOURCES] The discovery represents the Milky Way's earliest-known galactic merger. ca.news.yahoo.com · www.independent.co.uk
- [● 3 SOURCES] Astronomers used the Hubble and Gaia telescopes to study stellar clusters within the inner 20,000 light-years of the Milky Way. ca.news.yahoo.com · www.phonandroid.com · www.independent.co.uk
- [● 3 SOURCES] The absorbed dwarf galaxy is named Low-energy-Kraken-Heracles (LKH). ca.news.yahoo.com · www.phonandroid.com · www.independent.co.uk