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?
Materials:
- 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
White holes are theoretical cosmic regions that function in the opposite way to black holes. Just as nothing can escape a black hole, nothing can enter a white hole. Reminder, as of 2023, black holes have been well documented to exist. White holes are just theory.
Hey Aurora
Can you explain what a white hole is?
A human would be unconscious from the radiation long before spaghettification occurs.
Aurora,
Do you think a human is conscious and aware when they would become spaghetthified if they fell into a black hole? Do we think it would be painful? Or would they be unconscious by then?
Thank you for your insight on this!
With all mammals, hair follicle have cycles of growth and no growth. Various mammals have different hair growth cycles. After a certain amount of time, each piece of hair falls out and a new one starts in its place.
Thanks that cleared up a lot.
My cat went into a truck and the fan cut some hair off so I was wondering why, when hair grows (on a cat) it stops at a special length but, if it gets cut it grows again?
The space around black holes is not fully understood. Just like the star is more or less a sphere (like a ball), astronomers consider black holes to be a sphere. So there really isn’t a back or front.
I suppose that would be called “popping the balloon”.
The best example is the supermassive black hole at the center of our galaxy. We call it “Sagittarius A*”.
No, we wouldn’t be able to see the star because the light would be blocked. But even a regular star can block light if it is between us and another star.
To clarify, the earth orbits around the sun. We often think of the earth orbiting the sun. Actually, any two objects orbit a point that is common between them. The point is called the barycenter. Since the sun is so much bigger than the earth, their barycenter is within the sun.
The barycenter between the earth and its moon is within the earth’s surface. So we say that the Moon orbits the earth.
Black holes have a very strong gravitational pull. But they only pull things in if they get to close. Objects that fall into a black hole are pulled apart some energy and material is thrown out into space, but most material becomes part of the very dense core of the black hole. It is possible for stars to fall into a black hole, if they get to close. Scientists even think there are times there black holes collide with each other.
It is remarkably unlikely that a star and the earth could collide. Planets are much smaller than stars. If a star and a planet collide, the planet would be torn apart and then fall into the star. This is true even for Jupiter, which is still much smaller than a star.
Our sun is just another star. If two stars collide, they either tear each other apart, or form one big star. However, it is possible for the new, bigger star to explode. This is call a nova.
Actually most stars we see in the night sky are in with our eyes are much bigger than our sun.
Stars are very, very far apart from each other. So it is extremely unlikely that a star will ever interfere with our solar system.
All planets in our solar system have some sort of atmosphere. We don’t know very much about the atmospheres, (or lack of them) for planets outside our solar system (exo-planets).
When water freezes in an ice tray, the top layer of water often freezes before the rest of the cube. When this happens, a little hole sometimes remains in the surface of the ice. As water freezes, it expands. As water freezes in the middle of the cube, it is pushed out that little hole. This process creates the little spike you sometimes see in ice cubes.
does a black hole have a back and if so can a star, asteroid, planet etc. be sucked in through the back?
since we say were ‘blowing up a balloon’ what would you call it if you exploded one?
is there a black hole bigger than the biggest star? what is a name of a black hole ? i want to try to find one on stellarium.
could you see a star if a black hole was in front of it?
why if we are closer to earth than the moon but still in space do we not start revolving around it?
I also looove this science program and I really like your hair.
Do black holes suck stuff into them? And if so were do they go? Do the get crushed, vaporized, or just disappear? Do stars get sucked into black holes since black holes were stars? And another thing if a star were to crash into earth would the star burn the earth or would the star disappear because of our atmosphere ?? Since stars move why haven’t any cross paths with planets? Could a star explode a planet with no atmosphere? Are there planets with no atmosphere? What would happen if a star went through Jupiter or another gas planet? Would a star going through the sun create a solar flair? What would it look like? has it happened before? would the sun explode if a star bigger that the sun where to collide with it, I know there aren’t any stars bigger than the sun in the Milky Way but if there were?
Random Question not about astrophysics at all
I was having soup for lunch but it was too hot, so I got the ice out of the freezer. My question is why does the ice freeze with a icicle coming out the top? Its not like we freeze it upside down.
When we think of black holes, usually we think of them as pulling material in. However as they pull material in, that material heats up and can be expelled out with high amounts of energy that we can see as jets, or beams, that blast outward into space and slam into any surrounding material.
From Enora (Cypress, Texas) : When a star explodes, it becomes a black hole. When a black hole explodes, does it become anything?
Yes you can! Did you watch the time dilation videos in Unit 7?
Yes a binary system is where one star revolves around the other, or both revolve around a common center not inside either one.
“making seem to age 5 years, in 15 years.” I meant making you pretty much age 5 years while everyone else ages 15 years. would allow you to see 100 years into the future, without aging 100 years, the drawbacks being that you have to move pretty fast, you would have to wait for some time before reaching 100 years, and you wouldn’t be able to go back.
Can you really “time travel” with time dilation? Because I think that when you move at a certain speed you can essentially age slower so that people on earth would age normally, but they would seem to age slower than you, making seem to age 5 years, in 15 years.
Also, black holes are so good at turning things into energy that you could power Norway for a year by throwing 7 cats into a spinning black hole.
Two stars that revolve around each other called binary stars, right? Just asking because I’m curious.
I knew earth would never fall into a black hole
Is there really a BLACK HOLE in our galaxy?
How do you know that a BLACK HOLE can kill you?
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?
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!)
How do you know if time traveling is even possible??
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??
awesome, thanks! -Gabe
Maybe… and you might be the one to do it! 🙂
Thinking of how time changes with black holes, do you think we could use that science to create time travel?
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:
http://science.nasa.gov/science-news/science-at-nasa/2003/09sep_blackholesounds/
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?
my mom thinks its a nova special.
Can you point me to an article that you’re reading so I can understand more about what you’re referring to?
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.
I still don’t understand how x-rays are emitted from a black hole when not even light has the velocity to escape it.??
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?????????????
The pull of gravity is different (and very intense!) at your head than it is at your feet, so you get stretched!
Why do you turn into a noodle?????
id find the invisabel kid by footprint
Man That Video Was Long!
Good question… no one knows.
what is inside a black hole?
No, anitmatter is matter with opposite electrical charge, not opposite gravitational forces. Our universe couldn’t exist if that were the case!
Could antimatter have negative gravity?
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.)
What is a White Hole?
i loooooooooooove black holes
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?