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Black Holes in the Universe
Transcript of Black Holes in the Universe
A Universe full of Black Holes
Black Holes are...
• massive objects so dense that nothing (including light!) can escape their gravitational potential.
How can we detect Black Holes?
How big are Black Holes?
They come in all sizes, depending only on the mass of what made them.
Let's learn about Black Holes!
Can we see them?
How are they created?
How do they grow?
How big are they?
Do they die?
Some supermassive black holes are actively accreting the matter around them... we call these quasars.
Intense friction in the accretion disk produces huge amounts of heat and light, making the small region around the black hole brighter than all the stars in ~1000 galaxies combined!
When Black Holes Light Up!
Beacons in the Distant Universe
If you squished the Earth into a black hole, it would be the size of....
... a grape!
Micro-black holes are so small they have
almost zero mass.
They are created naturally by cosmic rays hitting our atmosphere and can also be produced in the man-made Large Hadron Collider (a 17-mile long particle accelerator in Switzerland).
Supermassive Black Holes
millions of times more massive than our Sun
are about the same size as our Solar System!
A black hole created by the death of a massive star ends up to be...
... only 5 kilometers in radius!
Because quasars are so uniquely bright,
we can see them from the very distant corners of the Universe - as much as 13 Billion light years away!
Our local supermassive black hole is about to feed!
26,000 light years away, in the center of our galaxy, the Milky Way's supermassive black hole is getting ready to consume a gas cloud about 3 times the mass of Earth.
Black Holes are...
• created in nature during the violent deaths (supernovae) of massive stars.
Common Misconceptions about Black Holes
Black Holes exist only in theory.
We have had good observational proof of the
existence of black holes for about 20 years, and we can even watch stars orbiting a black hole in the center of our own Milky Way Galaxy!
Black Holes are cosmic "vavcuum cleaners", sucking up everything in the Universe!
Actually, black holes have a gravitational attraction just like anything else with the same mass in the universe. What makes them special is that they are very dense. The mass of a black hole is very compressed, and as long as you stay outside the “horizon” (boundary), you won’t be trapped by it.
Our Sun will become a Black Hole when it dies.
Actually, stars have to be at least ~25 times more massive than our Sun to become a black hole at the end of their lives. Our Sun will evolve into a white dwarf, a small, hot star about the same size as Earth.
Do Black Holes Die?
We don't think so.. though theoretically they can slowly evaporate!