Was the Milky Way a Quasar?
PBS Space Time・13 minutes read
The Milky Way galaxy, once thought to have a calm history, has revealed violent past events, including the discovery of massive gamma ray structures called the Fermi Bubbles. These bubbles, originating from the central black hole, play a crucial role in understanding the galaxy's evolution and potential future events, emphasizing the importance of monitoring Sagittarius A* for insights into the Milky Way's activity.
Insights
- The Milky Way, despite its overall calm history, contains a massive black hole at its center, along with smaller black holes, hot gas clouds, and massive stars, hinting at a complex and dynamic internal structure.
- The discovery of the Fermi Bubbles, massive gamma ray structures formed through Inverse Compton Scattering, suggests a violent past for the Milky Way, with energy equivalent to 100,000 supernova explosions, potentially originating from a mini AGN phase near the central black hole.
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Recent questions
What are the Fermi Bubbles?
Massive gamma ray structures above and below Milky Way.
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The Universe: Countless Wonders of the Milky Way (S2, E4) | Full Episode | History
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Dark matter - what we're really made of | Michelle Thaller | TEDxBinghamtonUniversity
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Summary
00:00
"Violent Past and Potential Future of Milky Way"
- The Milky Way galaxy has a relatively calm history compared to other galaxies, but recent discoveries suggest a violent past that could recur.
- Despite the calmness of the Milky Way, it houses an enormous black hole at its center, along with smaller black holes, hot gas clouds, and massive stars.
- The Fermi Bubbles, massive gamma ray structures extending 25,000 light years above and below the Milky Way, were unexpectedly discovered.
- The Fermi Bubbles were hidden by the gamma ray glow of the Milky Way, but their high-energy gamma rays distinguished them.
- The Fermi Bubbles were formed through Inverse Compton Scattering, involving extremely energetic electrons interacting with light.
- The energy contained in the Fermi Bubbles is equivalent to that released by 100,000 supernova explosions.
- The Fermi Bubbles likely originated from a mini AGN phase triggered by gas influx or a star's proximity to the black hole, leading to star formation and supernova explosions.
- Recent studies using the MeerKAT telescope array discovered radio bubbles near the Galactic core, likely originating from the central black hole and magnetic field-accelerated electrons.
- The X-ray activity of the Milky Way's central black hole has been increasing, hinting at potential future events, although Earth's atmosphere absorbs most gamma rays.
- While the creation of new Fermi Bubbles may not be imminent, monitoring the activity of Sagittarius A* provides insights into its influence on the Milky Way.
14:29
"Concordance diagram reveals Earth's true age"
- In a crystal, the concordance diagram shows a linear correlation due to cracks, with lead-206 to uranium-238 ratios on the Y-axis and lead-207 to U-235 on the X-axis following a curved line. The U-238 decays quickly in the first few billion years, then U-235 dominates later, creating the classic concordia curve.
- Various historical claims on the Earth's age, from medieval Jewish scholars to Archbishop James Usher, are debunked, with the latter pinpointing the Earth's creation at 4004 B.C. on a Sunday at 9:00 A.M., which was proven incorrect due to a slight time discrepancy. Tasha Montgomery's zodiac reference is critiqued for overlooking the precession of the equinoxes, leading to the conclusion that Earth is a Taurus.
