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Gravity! in black holes and our Solar System

Gravity! in black holes and our Solar System

This presentation is for an interactive lesson for middle schoolers (grades 6-8; ages 11-14). The material covered in this lesson is drawn heavily from this lesson from AstroEDU: https://astroedu.iau.org/en/activities/1749/what-is-a-black-hole-lower-secondary-level/ and meets a Michigan Department of Education Science Performance Expectation.

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Abbie Stevens

April 24, 2019
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Transcript

  1. Gravity! In black holes and our Solar System Dr. Abbie

    Stevens Event Horizon Telescope
  2. Gravity • Gravity is a pulling force between two or

    more things with mass • The more mass something has, the stronger the gravitational field it produces • Two famous scientists who described gravity: Newton and Einstein • Mass curves space; the more mass, the more space is curved, and thus the more gravitational pull it has
  3. What is a black hole?

  4. Myth or Fact? Credit: Peter & Trent Ninos

  5. Black holes have enormous mass • Mass: 3 Suns to

    billions of Suns Credit: NASA Credit: NASA Credit: Creative Commons
  6. Black holes have a huge escape velocity • Earth’s escape

    velocity: ~25,000 mph • The Moon’s escape velocity: ~5,300 mph • A black hole’s escape velocity: 670 billion mph
  7. What is a black hole? • Powerful gravity • Even

    light cannot escape Credit: NASA 8,000 miles 2,160 miles 239,000 miles
  8. Do you really know gravity? • Space • Mass •

    Bending • Newton • Einstein
  9. Re-visiting: Myth or Fact? Credit: Peter & Trent Ninos

  10. Hunting for a black hole

  11. Watching a black hole eat Credit: NASA

  12. What if the black hole isn’t eating? Black hole as

  13. Watching a black hole bend light

  14. Gravitational forces in the Solar System

  15. Credit: caltiva

  16. Relative distances in our Solar System 3 Mercury: 1.5 yds

    Sun: 0 yds Neptune: 120 yds Venus: 2.9 yds Earth: 4 yds Mars: 6.1 yds Jupiter: 20.8 yds Saturn: 38.1 yds Uranus: 76.8 yds 3
  17. • Big swirling gas cloud flattens under its own gravity

    • Dust clumps into rocks, which clump into planetesimals, which attract more dust and rocks by their gravity, and become planets Real picture of a protoplanetary disk Credit: ALMA; C. Brogan; B. Saxon Protoplanetary nebula → protoplanetary disk
  18. Summary •Mass bends space to form a gravitational field •Black

    holes are ‘black’ because their escape velocity is faster than the speed of light •Gravity was important in the formation of our Solar System within the protoplanetary disk Event Horizon Telescope: first-ever picture of a black hole!
  19. Fitting the Solar System in this room: distance • Sun

    – Mercury: 35 million mi • Sun – Venus: 67 million mi • Sun – Earth: 93 million mi • Sun – Mars: 142 million mi
  20. Fitting the Solar System in this room: distance • Sun

    – Mercury: 35 million mi • Sun – Venus: 67 million mi • Sun – Earth: 93 million mi • Sun – Mars: 142 million mi • Sun – Jupiter: 484 million mi • Sun – Saturn: 889 million mi • Sun – Uranus: 1.79 billion mi • Sun – Neptune: 2.8 billion mi ← total size of Solar System
  21. Fitting the Solar System in this room: size • Sun:

    864,000 mi • Mercury: 3000 mi • Venus: 7500 mi • Earth: 7900 mi • Mars: 4200 mi • Jupiter: 89,000 mi • Saturn: 75,000 mi • Uranus: 32,000 mi • Neptune: 31,000 mi ← total size for comparison Credit: Universe Today
  22. More resources https://www.nasa.gov/topics/solarsystem/index.html https://www.universetoday.com/ https://exploratorium.edu/ronh/weight/ CrashCourse Astronomy by PBS on

    YouTube (10-15 min episodes on gravity, black holes, the Solar System, etc.)