Black Holes

With Death, Life Begins

Jiya Qin

2023/9/26

Contents

What is a black hole?

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• A black hole is a place in space where gravity pulls so much that even light can not get out
• No lower limit

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Formation & Structure

A Quick Recap

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BOOM BOOM (SUPER)NOVA

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Structure

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Schwarzschild Radius: The Point of No Return

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Hawking Radiation

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Classification & Growth

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Growth

Consuming Matter

Merging with Other Black Holes

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Three Properties of a Black Hole

Mass

Angular Momentum

Electric charge

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Does a Black Hole Have No Hair?

Is it true?

• Classical Newtonian Physics: Yes
• General Relativity: Not really…
• Multipoles beyond the mass monopole
• the presence of external matter

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Firewall Theorem

Is all information is lost?

Or a black hole is a super hard drive?

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Quasars

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• young, active galactic nucleus in early stages of the universe
•  emits radio waves and X-rays across the electromagnetic spectrum.
• massive 
• extremely remote (from earth)
• emitting exceptionally large amounts of energy
• typically having a starlike image in a telescope. 

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Primordial

Stellar

Intermediate

Supermassive

Smaller than 1M ⊙

Still a theory

2/3-100 M ⊙

Cygnus X-1

10^9∼10^10M⊙(Theoretically)

TON 618

Ultramassive

 100-10^5 M ⊙

GW190521

Mass

10^5-10^9 M ⊙

Sagittarius A*

Effects in the Universe

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On a smaller scale…

• They devour celestial bodies
• Produces Long Gamma Ray Bursts
• Disrupts the orbit around them

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Galaxies

• Galaxies that are still actively star-forming have younger stars are bluer, while galaxies that have mostly shut-down star formation are redder.
• Galaxies that have shut down star

formation are referred to as “quenched.” 

shoot gases out of their host and heat

The gases around makes them too hot to form

form stars

• The hot gases cools down in the halo and

forms stars

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The beginning and the end of the Universe?

Where it all Begins…

• Some scientist state that the universe was born from an infinite small point: a singularity
• a white hole?

The Grand Finale

• Most stars will turn into black dwarfs and neutron stars
• If the force of the expansion too great, matter will dissolve
• An era of black holes

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The fabric of Cosmos

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Is it possible to look at your back without turning?

Can we travel through a wormhole?

How to Find One

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GRAVITATIONAL �LENSING�

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• That’s the most common way we can “see”a black hole

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MATTER FALLING INTO IT

Interferometry

干涉测量

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Thanks

With Death, Life Begins

本人刚G1， 学识尚浅薄，欢迎提出改进意见。

Resources

How to quench a galaxy | astrobites

How can we detect black holes? | ChandraBlog | Fresh Chandra News (harvard.edu)

Physics - The Simplicity of Black Holes (aps.org)

gravity - Are there upper or lower mass limits for black holes? - Astronomy Stack Exchange

What Is a Black Hole? | NASA

Frank’s PPT From Last Year

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