How do scientists "see" black holes? with Skype A Scientist and MSU SciFest

These slides accompany a virtual presentation I give for middle school and high school science classes through the Skype A Scientist and MSU SciFest programs. I adjust the subset of slides I use based on the audience. There are videos in quite a few of the slides that don't render in the PDF version saved here.

You can read more about me and my background, and get in touch for a talk or creative project, on my website: https://abigailstevens.com/

Transcript

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

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2. First: what is
   astronomy?
   • Astronomy: stuff in
   outer space
   • Astrophysics: physics
   of stuff in outer space
   • Also: astrochemistry,
   astrobiology,
   heliophysics, Earth &
   planetary sciences,
   near-Earth space
   physics
   Image: NASA/ESA/HST
   Tools: math, computer programming,
   creative problem-solving, teamwork
   

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3. 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
   

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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”)
   

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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
   

   View Slide

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
   

   View Slide

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
   

   View Slide

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
   

   View Slide

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”)
   

   View Slide

10. Can’t just grab
    one, put it on a
    table, shine a
    light on it, and
    study it
    Video: NASA/GSFC/J. Schnittman
    Black holes
    To see it, need to
    wait for one to send
    light in our direction
    

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11. Image: Event Horizon Telescope
    collaboration
    How do
    we see
    them?
    taking a
    picture using
    radio light
    

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12. Image: Event Horizon Telescope
    collaboration
    How do
    we see
    them?
    taking a
    picture using
    radio light
    

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13. Image credit: NASA/CXC/M. Weiss
    How do
    we see
    them?
    eating its
    star-friend
    

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14. How do
    we see
    them?
    eating its
    star-friend
    Video credit: NASA
    

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15. The first black
    hole we saw is
    called Cygnus
    X-1, in 1972.
    How do
    we see
    them?
    eating its
    star-friend
    Image credit: NASA/CXC/M. Weiss
    

    View Slide

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

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17. The electro-magnetic spectrum
    How do
    we see
    them?
    with X-ray
    telescopes
    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!
    

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18. Video: NASA/GSFC
    How do
    we see
    them?
    with X-ray
    telescopes
    

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19. Black hole as ☆
    How do
    we see
    them?
    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
    

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20. Image credit: NASA/CXC/M. Weiss
    How do
    we see
    them?
    smashing
    together
    Video: S. Ossokine/A.
    Buonanno/T. Dietrich (MPI
    for Gravitational Physics)/R.
    Haas (NCSA)/SXS project
    

    View Slide

21. Image credit: NASA/CXC/M. Weiss
    Video: T. Ramirez/G.
    Lovelace/SXS
    Collaboration/LIGO-Virgo
    Collaboration
    How do
    we see
    them?
    smashing
    together
    

    View Slide

22. How do
    we see
    them?
    bending light
    from behind
    them
    

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23. Image: HST
    How do
    we see
    them?
    bending light
    from behind
    them
    The strong gravity of the black hole acts
    like a lens, bending and distorting the image.
    

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24. Image credit: NASA/CXC/K. Divona
    

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25. Dr. Abbie
    in school
    • Middle school and high school:
    physics, earth science, math,
    computer programming
    

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26. • Middle school and high school:
    physics, earth science, math,
    computer programming
    • College: small liberal arts college
    • BA, physics major, math minor
    Dr. Abbie
    in school
    

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27. • Middle school and high school:
    physics, earth science, math,
    computer programming
    • College: small liberal arts college
    • BA, physics major, math minor
    • Graduate school: large research
    universities
    • MSc in physics, in astrophysics
    group
    Dr. Abbie
    in school
    

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28. • Middle school and high school:
    physics, earth science, math,
    computer programming
    • College: small liberal arts college
    • BA, physics major, math minor
    • Graduate school: large research
    universities
    • MSc in physics, in astrophysics
    group
    • PhD in astronomy, in large
    astronomy research institute
    Dr. Abbie
    in school
    

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29. •Middle school and high school: physics,
    earth science, math, computer programming
    •College: small liberal arts college
    •BA, physics major, math minor
    •Graduate school: large research universities
    •MSc in physics, in astrophysics group
    •PhD in astronomy, in large astronomy
    research institute
    In high school, I wanted to do
    architecture and engineering, so I
    took physics and math. Then in
    physics I was introduced to
    astronomy!
    • Learn about things that interest
    you, and keep an open mind!
    Dr. Abbie
    in school
    

    View Slide

30. •Middle school and high school: physics,
    earth science, math, computer programming
    •College: small liberal arts college
    •BA, physics major, math minor
    •Graduate school: large research universities
    •MSc in physics, in astrophysics group
    •PhD in astronomy, in large astronomy
    research institute
    In high school, I wanted to do
    architecture and engineering, so I
    took physics and math. Then in
    physics I was introduced to
    astronomy!
    • Learn about things that interest
    you, and keep an open mind!
    In college, I changed majors twice!
    (environmental policy, theater),
    nearly added math as a double major
    • It’s ok to change your mind!
    Dr. Abbie
    in school
    

    View Slide

31. •Middle school and high school: physics,
    earth science, math, computer programming
    •College: small liberal arts college
    •BA, physics major, math minor
    •Graduate school: large research universities
    •MSc in physics, in astrophysics group
    •PhD in astronomy, in large astronomy
    research institute
    In high school, I wanted to do
    architecture and engineering, so I
    took physics and math. Then in
    physics I was introduced to
    astronomy!
    • Learn about things that interest
    you, and keep an open mind!
    In college, I changed majors twice!
    (environmental policy, theater),
    nearly added math as a double major
    • It’s ok to change your mind!
    • Keep your hobbies!
    • Mental wellbeing is so important!
    Dr. Abbie
    in school
    

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32. Job prospects
    in astronomy
    • Academia
    • Researcher
    • Professor (research +
    teaching)
    • Lecturer/instructor
    (teaching)
    • Education and public outreach
    • Planetarium director
    • Outreach coordinator
    • Content at educational
    nonprofits
    • Industry
    • Data science
    • Quantitative analytics
    • Software development
    

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33. Image: NASA/JPL-Caltech
    Q&A time!
    

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