• Privacy
  • Contact
  • Home
  • Astronomy
  • Biology
  • Ecology
  • Psychology
  • Physics
  • Other
No Result
View All Result
Busy Mind Thinking
  • Home
  • Astronomy
  • Biology
  • Ecology
  • Psychology
  • Physics
  • Other
No Result
View All Result
Busy Mind Thinking
No Result
View All Result

The Static Isolated Black Hole

in Astronomy
Home Astronomy
Share on FacebookShare on Twitter


The simplest idealized black hole is the static isolated black hole. Real stars or black holes will rotate and not be static. Black holes in binary systems will not be isolated. Even if not very realistic, the idealized case does help us begin to understand the properties of static isolated black holes.

Table of Contents

  • Static Isolated Black Hole
    • Event Horizon of a Static Isolated Black Hole
      • Circumference Rather Than Radius
      • Photon Sphere
      • Inside the Event Horizon of a Static Isolated Black Hole

Static Isolated Black Hole

Physicists often approach difficult problems by making idealized approximations to get a basic understanding. They then add complexities to gain a more realistic understanding of the real situation.

Event Horizon of a Static Isolated Black Hole

The boundary of the black hole is called the Schwarzschild radius or event horizon. At this boundary, the escape velocity equals the speed of light. From just outside the Schwarzschild radius, it is possible to escape the black hole by traveling outward at the speed of light.

From just inside, no escape is possible because the escape velocity exceeds the ultimate speed limit for the universe, the speed of light.

For a star the mass of the Sun, the Schwarzschild radius is about 3 kilometers. Its size is linearly proportional to the collapsed mass. A two solar mass black hole would have a Schwarzschild radius of 6 kilometers. A 10 solar mass black hole, 30 kilometers and so on.

Circumference Rather Than Radius

Astrophysicists specializing in black holes worry about a technicality. In normal flat space, the diameter and circumference of a circle or sphere have a simple and well known relation. The circumference is simply pi times the diameter.

However, near a black hole, space is so distorted that this simple relationship does not hold. Because the circumference of a static isolated black hole is farther from the center of this distortion, it is less distorted than the diameter or radius. Hence, black hole astrophysicists often prefer to talk about the circumference rather than the radius of a black hole.

Most people, however, are more familiar with the radius of a circle or sphere than the circumference. Hence, many ignore this technicality. References to the radius of a black hole refer to the radius it would have had space not been so distorted by the presence of the black hole.

Photon Sphere

Nothing can escape from the event horizon of a static isolated black hole. From just outside the event horizon, it is possible to escape by traveling at the speed of light, but escape is not automatic.

A space shuttle must be launched at an escape velocity to escape Earth’s gravity, but there is an additional requirement. It must be launched fairly close to straight up. Otherwise, the rocket will fall back to Earth, even if launched at its escape velocity.
Escaping from just outside the event horizon has a similar requirement.

A photon of light, which will of course be traveling at the speed of light, can escape from just outside the event horizon, but it must travel nearly straight outward. The directions are close enough to straight out that they allow the photon to escape from a cone called the exit cone.

Photons outside the event horizon that are moving outward outside the exit cone will fall back into the black hole even though they are traveling faster than the escape velocity. A photon pointed outward on the boundary of the exit cone will neither escape from nor fall back into the static isolated black hole.

It will simply orbit the black hole. This region outside the event horizon where the gravitational force is strong enough to allow photons to orbit the static isolated black hole is called the photon sphere.

Inside the Event Horizon of a Static Isolated Black Hole

Inside the event horizon, a static isolated black hole has a singularity point at the center, containing all the mass. The event horizon of a static isolated black hole, or Schwarzschild radius, surrounds the singularity and represents the boundary where the escape velocity equals the speed of light.

Read more:

Acceleration of a static observer near the event horizon of a static isolated black hole

The infalling photon, the infalling particle, and the observer at rest near the horizon of a static isolated black hole

Tags: black holegalaxy

Related Posts

Mysterious Matter in the Universe
Astronomy

Mysterious Matter in the Universe

The Evolution of Stars
Astronomy

The Evolution of Stars

Life of Stars: Birth and Death of Stars
Astronomy

Life of Stars and Death of Stars

Variable Stars: Stars that Change in Brightness
Astronomy

Variable Stars: Stars that Change in Brightness

Dark Matter Has Been Found in a Galaxy Cluster
Astronomy

Dark Matter Has Been Found

Black Holes: Where Gravity has Gone Wild
Astronomy

Black Holes: Where Gravity has Gone Wild

Galactic Clusters: Astronomical Clustering of Stars
Astronomy

What are Galactic Clusters?

Next Post
6 Steps To Master The World of Educational Consulting

6 Steps To Master The World of Educational Consulting

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

I agree to the Terms & Conditions and Privacy Policy.

Busy Mind Thinking

One of the most powerful abilities of a human being is the capacity to use our thoughts to create our reality and interpret things in a more empowering way.

Categories

  • Astronomy
  • Biology
  • Ecology
  • Other
  • Physics
  • Psychology

Tags

ecology education energy galaxy gifted education happiness plants psychology types of energy universe

Recent News

What is the planning fallacy?

What is the planning fallacy?

What is the plate tectonics theory?

What is the plate tectonics theory?

  • Privacy
  • Contact

© 2021 busymindthinking.com

No Result
View All Result
  • Home
  • Astronomy
  • Biology
  • Ecology
  • Psychology
  • Physics
  • Other

© 2021 busymindthinking.com

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.