Special Science Teleclass: Black Holes

This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too!

We’re ready to deal with the topic you’ve all been waiting for! Join me as we find out what happens to stars that wander too close, how black holes collide, how we can detect super-massive black holes in the centers of galaxies, and wrestle with question: what’s down there, inside a black hole?


  • marble
  • metal ball (like a ball bearing) or a magnetic marble
  • strong magnet
  • small bouncy ball
  • tennis ball and/or basketball
  • two balloons
  • bowl
  • 10 pennies
  • saran wrap (or cup open a plastic shopping bag so it lays flat)
  • aluminum foil (you’ll need to wrap inflated balloons with the foil, so make sure you have plenty of foil)
  • scissors
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31 Responses to “Special Science Teleclass: Black Holes”
  1. bac051201 says:

    I used a basketball and a football

  2. Reena Willamson says:

    I knew earth would never fall into a black hole

  3. Reena Willamson says:

    Is there really a BLACK HOLE in our galaxy?

  4. Reena Willamson says:

    How do you know that a BLACK HOLE can kill you?

  5. Aurora says:

    That can’t ever happen, because we’re not anywhere NEAR any black holes! And since nothing could escape a black hole once past it’s event horizon… well, did you have another question?

  6. Aurora says:

    Check out the videos in Unit 7, and based on physics you’ll learn how physicists think about it. (You actually time travel every time you look through a telescope!)

  7. Reena Willamson says:

    How do you know if time traveling is even possible??

  8. Reena Willamson says:

    hi I was thinking what would happen if earth would happen to fall into a BLACK HOLE and how would we escape it if it did??

  9. Melanie Williamson says:

    awesome, thanks! -Gabe

  10. Aurora says:

    Maybe… and you might be the one to do it! 🙂

  11. Melanie Williamson says:

    Thinking of how time changes with black holes, do you think we could use that science to create time travel?

  12. Aurora says:

    You’ve asked a lot of great questions. Let me point you in the right direction so you can continue to answer your own questions (that’s what great scientists do!)

    All atoms have mass, and anything with mass has gravity. Black holes have a lot of atoms squished together into a very small space, so they have a lot of gravitational force associated with them. Black holes are objects that have so much gravity that the escape velocity is greater than the speed of light.

    Here’s information about a black hole that is generating sound waves 57 octaves below middle C in the Perseus Cluster:

  13. James says:

    Hello Mrs. Lipper, Thank you for such a fascinating video! Quick question…maybe…If black holes are made up of only time and space into which supernova particles are sucked, then how can they produce gravity? To have gravity you need mass, right? But in the vacuum of space there are only a few helium and hydrogen atoms (or so I have read). Does that mean that black holes are made up of time, hydrogen, and helium? What does space consist of that it can be distorted by gravity?

    On a side note (you probably already know about this), I just read an article about black holes making noise. We cannot hear the noise, of course, but we can see the sound waves moving through the particles leaked by the black holes and nearby galactic gas. The peaks and troughs of the sound waves can be detected by respectively brighter and dimmer x-rays. I wonder, can we detect black holes by the sound waves they produce?

  14. Courtney Caron says:

    my mom thinks its a nova special.

  15. Aurora says:

    Can you point me to an article that you’re reading so I can understand more about what you’re referring to?

  16. Aurora says:

    Scientists don’t think that the x-rays come from the black hole itself (inside the point of no return), but rather the strong gravitational pull of the black hole causes objects to squeeze and accelerate on its way in, and some of these particles are jetted out into space before they actually cross the threshold due to the path they take in the accretion disk.

  17. Courtney Caron says:

    I still don’t understand how x-rays are emitted from a black hole when not even light has the velocity to escape it.??

  18. Courtney Caron says:

    theirs a new theory that the black hole doesn’t suck in things but it just bends light could you explain this to me i don’t get it?????????????

  19. Aurora says:

    The pull of gravity is different (and very intense!) at your head than it is at your feet, so you get stretched!

  20. Chris Thornhill says:

    Why do you turn into a noodle?????

  21. Lisa Dage says:

    id find the invisabel kid by footprint

  22. Lisa Dage says:

    Man That Video Was Long!

  23. Aurora says:

    Good question… no one knows.

  24. Kaye Nielsen says:

    what is inside a black hole?

  25. Aurora says:

    No, anitmatter is matter with opposite electrical charge, not opposite gravitational forces. Our universe couldn’t exist if that were the case!

  26. Christian Engman says:

    Could antimatter have negative gravity?

  27. Aurora says:

    A white hole only exists on paper – it’s purely theoretical, meaning that no one has ever see one.

    It’s a time reversal of a black hole, which means that the event horizon (the disk that forms around the hole itself) instead of attracting material in (the way a black hole does), a white hole spits light and matter out. The white hole still attracts matter the way a black hole does, however the event horizon would move away from matter so that nothing could ever cross it and enter the white hole.

    As a side note: a white hole is what happens when you write down a complicated set of equations and geometry to describe a black hole and set the mass at the center to zero, which doesn’t happen in the real world (you can’t collapse a star and wind up with no mass.. a black hole is a star that is collapsing forever.)

  28. Laura Swick says:

    What is a White Hole?

  29. Dolores Andral says:

    i loooooooooooove black holes

  30. Aurora says:

    Our supermassive black hole at the center of our galaxy isn’t actually feeding right now – stuff has to fall in for it to be eating. And we’re also orbiting at a pretty good clip and not on a path that would take us into the black hole. Does that help?

  31. Kristi Kerr says:

    Hi! We would like to know if a black hole is at the center of our galaxy, why aren’t we sucked in?

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