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All black holes great and small

All stars bright and beautiful,
All black holes great and small,
All spirals and ellipticals,
‘Twas gravity built them all.

Long-time readers no doubt already know this, but I love all black holes, great and small. Of the many topics I write about, I think black holes may be my favorite: they are laboratories for the most extreme gravity in the Universe, but also shapers of their host galaxies through the material they churn. Even though their reputation is that of a cosmic vacuum cleaner, they pump a lot of matter into the surrounding space; thanks to the light that material emits, black holes rank as some of the brightest objects in the Universe.

The radio galaxy Hercules A, seen in visible light (the galaxy at the center, background galaxies) and radio light, which shows the huge jets of matter streaming from the galaxy's central black hole. [Credit;  NASA, ESA, S. Baum & C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)]

The radio galaxy Hercules A, seen in visible light (the galaxy at the center, background galaxies) and radio light, which shows the huge jets of matter streaming from the galaxy’s central black hole. [Credit; NASA, ESA, S. Baum & C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)]

Quasars and blazars, ergospheres and event horizons: all of these things are topics in my upcoming CosmoAcademy class, “Introduction to Black Holes”. This online course begins next Tuesday, October 1, and runs for four 1-hour sessions. The class meets from 9  to 10 PM US Eastern time. Sign up today! No prior knowledge of black holes is required, and we’ll discuss the following subjects (though probably not in this particular order):

  • What is a black hole? How gravity bends light, and extreme gravity can trap light
  • The structure of a black hole: event horizons, ergospheres, and the “no-hair” theorem
  • Observations of black holes: from Cygnus X-1 to supermassive black holes in galactic centers
  • Active galactic nuclei: how black holes can become some of the brightest objects in the cosmos
  • Role of black holes in shaping galaxies: accretion, jets, and feedback
  • At the event horizon: black hole entropy, Hawking radiation, evaporation
  • Other topics as we have time and interest!

Update: due to an error in the ticket price, this class was twice as expensive as it should have been. The correct price should be a lot more palatable!

 

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