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Great Lakes Lectures: How do we "see" black holes?

Great Lakes Lectures: How do we "see" black holes?

This talk was given in the Great Lakes Lectures series on May 27, 2021. Note that gifs and videos won't render in the pdf here.

Watch a video of me giving this talk (and struggle as a weather forecaster) here! https://www.facebook.com/101977881748388/videos/765172087493089

Description:
Black holes formed from dying stars are the densest things in the universe. They have ten to one hundred times the mass of the Sun crammed into a space that is only tens of miles across. Black holes get their name because their gravity is so strong that not even light can escape, so they look black to us. However, even though light can't escape from inside them, we still know where lots of them are. Scientists can find and study black holes from effects they have on the space environment around them. In this talk, I'll tell you about the ways we have of finding black holes and learning more about their extreme physics.

More information:
https://science.nasa.gov/astrophysics/focus-areas/black-holes https://wkar.pbslearningmedia.org/resource/black-holes-crashcourse-1033/black-holes-crash-course-astronomy/

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Abbie Stevens

May 27, 2021
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Transcript

  1. Image: NASA/JPL-Caltech How do we “see” black holes? Dr. Abbie

    Stevens Great Lakes Lectures
  2. Black holes • A lot of stuff (mass) in a

    very small space • Very powerful gravity • Escape velocity faster than the speed of light! Image: J. Provost, ScienceNews.org imagine 3D space like a 2D fabric
  3. Video: NASA/GSFC/J. Schnittman Black holes • Event horizon • Singularity

    • Photon sphere • Accretion disk Not pictured: relativistic jets The “danger zone” is very small!
  4. Black holes Image: Event Horizon Telescope collaboration No limit on

    how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”)
  5. Black holes Image: Event Horizon Telescope collaboration No limit on

    how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”) Quick interlude: Universe is really big, numbers get really big
  6. Black holes Image: Event Horizon Telescope collaboration No limit on

    how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”) Quick interlude: Universe is really big, numbers get really big 1 thousand seconds ≅ 16 minutes
  7. Black holes Image: Event Horizon Telescope collaboration No limit on

    how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”) Quick interlude: Universe is really big, numbers get really big 1 thousand seconds ≅ 16 minutes 1 million seconds ≅ 11 days
  8. Black holes Image: Event Horizon Telescope collaboration No limit on

    how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”) Quick interlude: Universe is really big, numbers get really big 1 thousand seconds ≅ 16 minutes 1 million seconds ≅ 11 days 1 billion seconds ≅ 32 years
  9. Black holes Image: Event Horizon Telescope collaboration Biggest black hole

    ever seen: 60 Billion times the mass of our Sun Smallest black hole ever seen: 3 times the mass of our Sun No limit on how big they can get! Small black holes are formed from the death and collapse of a big star (“stellar” or “stellar mass”) Big black holes have been around since very early in the universe, at the centers of galaxies (“supermassive”)
  10. Can’t just grab one, put it on a table, shine

    a light on it, and study it Video: NASA/GSFC/J. Schnittman How do we study them? To see it, need to wait for one to send light in our direction We “see” black holes by looking at effects on their space environment
  11. Image: Event Horizon Telescope collaboration Taking a picture using radio

    light
  12. Image: Event Horizon Telescope collaboration Taking a picture using radio

    light Computer simulation showing what it might look like if we had higher- resolution images
  13. Image: NRAO/AUI Taking a picture using radio light

  14. Image: ESO/O. Furtak Taking a picture using radio light

  15. Taking a picture using radio light Image: NRAO

  16. Image: Event Horizon Telescope collaboration Taking a picture using radio

    light Lines show polarization of the light
  17. Image credit: NASA/CXC/M. Weiss Eating its star-friend (X-ray binaries) Star

    friend Black hole Accretion disk
  18. Image credit: NASA/CXC/M. Weiss Star friend Black hole Accretion disk

    20 million degrees F Eating its star-friend (X-ray binaries)
  19. Video credit: NASA Eating its star-friend (X-ray binaries)

  20. The first black hole we saw is called Cygnus X-1,

    in 1972. Eating its star-friend (X-ray binaries) Image credit: NASA/CXC/M. Weiss
  21. Type of light Gets through Earth’s atmosphere? Approx. scale of

    wavelength? The electro-magnetic spectrum The colors that we see are a very small part of all the types of light that exist. Images: Shutterstock, NASA X-ray telescopes
  22. The electro-magnetic spectrum Type of light Gets through Earth’s atmosphere?

    Approx. scale of wavelength Images: Shutterstock, NASA X-rays from space can’t get through Earth’s atmosphere, so we put X-ray telescopes on satellites and launch them into space on rockets! X-ray telescopes
  23. Video: NASA/GSFC Image: Caltech X-ray telescopes

  24. Eating other gas (AGN & quasars) Image credit: NASA/CXC/M. Weiss

    Chandra Deep Field Low X-ray Mid X-ray High X-ray Video: NASA/CXC/SAO/K. Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)
  25. Black hole as ☆ Nearby orbiting stars Sagittarius A-star (Sgr

    A*) at the center of our Milky Way galaxy! 4.3 million times the mass of the Sun
  26. Image credit: NASA/CXC/M. Weiss Smashing together Video: S. Ossokine/A. Buonanno/T.

    Dietrich (MPI for Gravitational Physics)/R. Haas (NCSA)/SXS project
  27. Image credit: NASA/CXC/M. Weiss Smashing together Video: T. Pyle, Caltech/MIT/LIGO

    Lab LIGO Virgo
  28. Image credit: NASA/CXC/M. Weiss Smashing together Image & video: Caltech/MIT/LIGO

    Lab
  29. Image credit: NASA/CXC/M. Weiss Video: T. Ramirez/G. Lovelace/SXS Collaboration/LIGO-Virgo Collaboration

    Smashing together
  30. Bending light from behind them

  31. Bending light from behind them Image: NASA

  32. Image: NASA/ESA/HST Bending light from behind them The strong gravity

    of the black hole acts like a lens, bending and distorting the image. Image: J. Rhoads(ASU)/WIYN/ AURA/NOAO/NSF
  33. Bending light from behind them Image: NASA/ESA/HST

  34. Image: NASA/JPL-Caltech How do we “see” black holes? Taking a

    picture using radio light Eating its star-friend Nearby orbiting stars Bending light from behind them Smashing together Eating other gas
  35. Q&A time! Image: NASA/JPL-Caltech alstev@msu.edu @abigailStev github.com/abigailStev Dr. Abbie Stevens

    Great Lakes Lectures
  36. Q&A time! Image: NASA/JPL-Caltech alstev@msu.edu @abigailStev github.com/abigailStev Dr. Abbie Stevens

    Great Lakes Lectures
  37. Image credit: NASA/CXC/K. Divona

  38. RXTE Science drivers: spin distribution of black holes, accretion disk

    winds, disk-jet connection, neutron star equation of state, burst oscillations, gamma-ray bursts, LIGO counterparts, tidal disruption events, discovering new sources, etc! Video from NASA Mission Design Lab, April 2018 § Proposed Probe-class space telescope, “medium” budget: $1B for development and 5 years of operations § Combines strengths of NICER and LOFT: high throughput X-ray timing with good spectroscopy § If selected, launch in 2032 on a Space-X Falcon Heavy