Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine...

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Goal: To understand special stars. Objectives: 1) To learn the basics about Black holes 2) To examine the different sizes/masses of Black holes 3) To learn about the physics inside a black hole 4) To explore Kerr black holes. 5) To explore Hawking Radiation 6) To learn about some other black hole oddities

Transcript of Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine...

Page 1: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Goal: To understand special stars.Objectives:

1) To learn the basics about Black holes2) To examine the different sizes/masses of

Black holes3) To learn about the physics inside a black

hole4) To explore Kerr black holes.

5) To explore Hawking Radiation6) To learn about some other black hole

oddities

Page 2: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

What is a black hole

• As we saw before an object dense enough or massive enough such that the escape velocity is the speed of light

Page 3: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Event Horizon

• = Goodbye Forever (takes infinite time to pass through it)

• Is the surface where the escape velocity is the speed of light

• Is the effective radius of the black hole

• Rs = 1.5 km * Mass of black hole (in solar masses)

Page 4: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

However

• Black holes are very rare.

• They also come in many sizes/masses.

Page 5: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Solar Mass Black Holes

• These are black holes that are 5-50 times the mass of our sun.

• They are formed from the deaths of massive stars.

• If on their own they are very tough to find as we can only see black holes when they interact with other objects.

Page 6: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Black Holes in binaries

• Just like with Neutron stars and white dwarfs, black holes will create an accretion disk.

• However, you can see nothing from the actual accretion, so all you get to see is the accretion disk.

• On the plus side, the accretion disk goes down to a few km in size at which point the gas has been heated quite a bit (infalling gas is slowed by frictional heating and interactions with the magnetic field).

• The innermost parts will emit X-rays!

Page 7: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Black holes in Globular Clusters

• In the centers of Globular Clusters, where stars are very tightly packed we often find black holes

• These black holes can be a few thousand times the mass of our sun.

• There also seems to be a correlation between cluster mass and black hole mass.

Page 8: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Galactic Center Black Holes

• Every galaxy we can peer into its center has a black hole that is millions of solar masses to billions.

• Ours is 4 million.

• Andromeda is about a billion.

Page 9: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Astro-mercial• But wait there’s more!

• JETS!• Materials racing

outward at close to

the speed of light

and going for up to

millions of light

Years!• (NGC 5532)

Page 10: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Physics outside a black hole

• We have 4 known dimensions

• 3 real spatial

• 1 real time

• Real Distance = Real Velocity * Real Time

• Real Acceleration = Change in Real Velocity / Real Time

Page 11: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Inside a black hole:

• Tobject = Tuniversal / (1 – rs / r)1/2

• So, when r > Rs then we have the square root of a negative number.

• What does that give us?

Page 12: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Imaginary Time

• So, time is not real but in terms of i (i = square root of -1)

• In our 4 dimensional physics world this messes up everything…

• So how can the Laws of Physics not work and still be Laws?

Page 13: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Maybe not

• M-Theory (not really a “Theory” more a “Model”, but M-Model does not sound impressive)

• 11 dimensions

• So, what makes no sense in 4 dimensions might make sense in 11.

• (so might have 3 real spatial, 3 imaginary spatial, real time, imaginary time, and 3 more dimensions)

Page 14: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

So

• Black Holes may have a key in unlocking the mysteries of the universe.

• However, we have no idea what happens to the stuff inside the black hole.

• Does it all collapse to center, or just get converted to energy?

Page 15: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Properties

• Even though the physics fail as we currently understand them in our 4 D worldview Black Holes still have properties

• They have magnetic fields

• Some have spin.

Page 16: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Kerr Black Holes

• Kerr Black Holes are black holes with spin.

This gives

them a

different

structure

Page 17: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Spin Energy

• In the distant future you can actually take the spin energy out of a Kerr Black Hole and use it!

• However the closest black hole is > 1000 light years away so…

Page 18: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Oddity

• Too much spin and the event horizons go away

• This would create a “naked singularity”

Page 19: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Hawking’s Radiation

• Space is NOT empty, it has energy!

• Everywhere in space you are constantly forming pairs of particles.

• One with + energy, one with -.

• They usually run into other particles and destroy themselves.

Page 20: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Near an event horizon

• There is a chance for the negative energy particle to quantum tunnel through the event horizon and end up inside the black hole

• The positive energy particle then escapes from the black hole (making it appear that the particle came from inside the black hole)

• Since energy is mass that means the black hole looses mass!

Page 21: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

However

• This process for known black holes will not start (due to getting more energy from the universe and radiation from the universe than they would loose) for a long time

• The smaller black holes will last a google years.

• The bigger ones even longer.

Page 22: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Wormholes + White Holes

• If you bend space time enough it makes it very easy to get to another place

• Black holes are one way to do that• However, it is problematic

• White holes are the opposite.• You go into a black hole, and shoot out a White hole.• Warning: the white hole you exit would not be in our

universe but would be in a negative space universe• 2nd warning: UNSTABLE! Just you entering might be

enough to destablize

Page 23: Goal: To understand special stars. Objectives: 1)To learn the basics about Black holes 2)To examine the different sizes/masses of Black holes 3)To learn.

Conclusion

• We have learned a whole lot about black holes.

• They exist and are here and there, but are rare.

• They come in more than 1 flavor

• They might be pointing towards other areas/laws of Physics


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