Black Holes Overview

What does the black hole no hair theorem state?

What happens to a star when its core is iron and its mass is less than 1.4 solar masses?

What is the result of a star with a final mass greater than 3 solar masses after a supernova event?

Why does a star between 1.4 and 3 solar masses form into a neutron star rather than a black hole after a supernova?

What is the source of the magnetic fields that produce jets of high-energy particles rushing away from black holes?

How do tidal forces change with the mass and size of a black hole?

How long are quasars typically active for?

What could potentially revive a dead quasar according to the text?

What is the key feature of an area of space-time that defines a black hole?

How is the escape velocity of an object related to its mass and distance from the center of a black hole?

According to Einstein's Theory of General Relativity, what does gravity do to space-time?

What is a key challenge with using 2-dimensional illustrations to represent black holes' warping of nearby space-time?

Black Hole Theorems

The no-hair theorem states that a black hole has only three hairs: its mass, electric charge, and angular momentum.

Stellar Evolution

When a star's core is iron and its mass is less than 1.4 solar masses, it collapses and forms a white dwarf.
A star with a final mass greater than 3 solar masses forms a black hole after a supernova event.
A star between 1.4 and 3 solar masses forms a neutron star after a supernova because its gravity is not strong enough to overcome neutron degeneracy pressure.

Black Hole Properties

Magnetic fields around black holes produce jets of high-energy particles.
Tidal forces around a black hole change with the mass and size of the black hole, with stronger forces near smaller black holes.
The escape velocity from a black hole is related to its mass and distance from the center, with more massive black holes having higher escape velocities.

Quasars

Quasars are typically active for a relatively short period, around 1-10 million years.
A dead quasar can potentially be revived by the merger of two galaxies, which can reignite the flow of gas and dust into the supermassive black hole.

Space-Time and Gravity

The key feature of an area of space-time that defines a black hole is the event horizon, beyond which nothing, including light, can escape.
According to Einstein's Theory of General Relativity, gravity warps space-time, causing objects to move along curved trajectories.
A key challenge with using 2-dimensional illustrations to represent black holes' warping of nearby space-time is that they cannot accurately depict the complex, three-dimensional curvature of space-time.

Explore the fundamental properties and types of black holes, including normal-sized, microscopic, and super-massive black holes. Learn about how normal black holes are formed through the death of massive stars.