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Title Page Janet Moore NASA Educator Ambassador. What is a Black Hole? Definition: a place where the escape velocity is faster than the speed of light.

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Presentation on theme: "Title Page Janet Moore NASA Educator Ambassador. What is a Black Hole? Definition: a place where the escape velocity is faster than the speed of light."— Presentation transcript:

1 Title Page Janet Moore NASA Educator Ambassador

2 What is a Black Hole? Definition: a place where the escape velocity is faster than the speed of light.

3 Close-up Picture of a Black Hole

4 Escape Velocity Definition: the velocity at which something must travel away from an object such that the gravity of the object cannot stop it.

5 Escape Velocity (2) Escape velocity depends on thegravity of the object

6 Escape Velocity (3) Low mass Medium mass High mass Very high mass for a given radius ^

7 Escape Velocity (4) radius decreasesincreases

8 What is a Black Hole? Its an object of high enough mass and small enough radius such that the escape velocity is faster than light. Nothing can escape.

9 Or, put another way …

10 The First Way A Black Hole Can Kill You Falling in

11 Down the Drain

12 Forcing the Issue The force of gravity from an object depends on 1) the mass of the object 2) your distance from it Black holes are really massive, And you can get really, really close But this means…. Gm 1 m 2 F= r 2 So if its really massive, or youre really close, the force is high.

13 Forcing the Issue (2) The force you feel CHANGES as you get closer. Something closer to the black hole feels MORE force. If you fall in feet first, you have a problem. STRETTTTTCH!

14 There is a Tide The change in force is called a TIDE Tides on surface of Earth (distance = 6400 km) : 1/1,000,000 th of a g DISTANCEFORCE (g) 6400 km , ,000,000 BLACK HOLE TIDES 6400 km F up F down (for a 3 solar mass black hole)

15 The Second Way A Black Hole Can Kill You Falling in Spaghettification

16 Why the long face?

17 The Third Way A Black Hole Can Kill You Falling in Spaghettification Be near one when its born

18 Cold War, Hot Topic Vela Satellites flown to detect nuclear explosions on Earth in 1960s and 1970s by looking for gamma rays Over their lifetime, they detected 73 events. NOT ONE WAS OF THIS EARTH

19 Gamma Ray Bursts GRBs happen every day, somewhere in the Universe

20 The Birth of a Black Hole Hypernova! Coalescing neutron stars

21 Birth Pangs Energy generated in a GRB = ergs This is 10x the Suns total energy over its entire lifetime. Enough energy to vaporize the Earth 100 billion times over.

22 Pfffssssst!

23 NASAs Swift Response Swift detects >100 GRBs per year Launched November 20, 2004

24 The Fourth Way A Black Hole Can Kill You Falling in Spaghettification Be near one when its born Be near one when it dies

25 Pare Production Particles created here Buh bye! Free at last! Black hole Hawking Radiation: 2 particles created, one particle leaves Net Effect: Black holes radiate away energy

26 Size Does Matter Hawking radiation depends on size/mass of the black hole: smaller holes radiate faster! In fact, radiation emitted goes as 1/mass 3 Stellar black hole lives for years A mini black hole (mass =10 12 kg) would be exploding now Emits higher energy radiation faster as size shrinks. KABOOM!

27 The Fifth Way A Black Hole Can Kill You Falling in Spaghettification Be near one when its born Just passing through Be near one when it dies

28 not Its a Wonderful Day in the Neighborhood not Its a Wonderful Day in the Neighborhood

29 What if... What would happen if the sun became a black hole?

30 Solar System Black Hole

31 The Sixth Way A Black Hole Can Kill You Falling in Spaghettification Be near one when its born Just passing through Be nearby when they merge Be near one when it dies

32 When Galaxies Collide

33 Wave Bye Bye Gravitational waves expand and contract space itself

34 The Long and the Short of It

35 ESAs Response: LISA 3 Wagon wheels That will detect passing gravitational waves Target launch: 2014

36 The Seventh Way A Black Hole Can Kill You Falling in Spaghettification Be near one when its born Just passing through Be nearby when they merge Be near one when it dies Fried by the light

37 Traveling Companion HD : just your typical bloated supergiant star… but it has a secret HD in X-rays (100,000x energy of Sun!) Cygnus X-1 Hey, where is it?

38 The Hideous Vortex

39 Disks and Fields and Jets, Oh My

40 Not-so-compact Disk

41 Angry Neighbors Cygnus A M 87 (600 million light years) (60 million light years)

42 Our GLAST (Fermi) Resort Gamma-Ray Large Area Space Telescope Launched: June 2008 Fermi will see thousands of active galaxies

43 The Seven Ways A Black Hole Can Kill You Falling in Spaghettification Be near one when its born Just passing through Be nearby when they merge Fried by the light Be near one when it dies

44 Whats on the other side…?

45 Questions?

46 The Sky by Eye

47 DIRBEs Milky Way

48 EXTREME Close up

49 The Monster in the Middle

50 Video Disk


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