Are black holes white or monochromatic?

In summary, the conversation discusses the topic of black holes and Hawking radiation. It is mentioned that black holes are perfectly black according to classical physics and emit Hawking radiation, which approximates a black body and emits a broad range of wavelengths. However, for black holes larger than our moon, the radiation temperature would be less than the cosmic background.
  • #1
newjerseyrunner
1,533
637
I was asked if black holes are white today. I answered no, they're perfectly black to fit with classical physics since it's a high school kid who asked.

It did get me thinking about Hawking radiation though and I haven't been able to find an answer to my question online. Is Hawking radiation broadband or does it only emit photons at very specific energy levels?
 
Astronomy news on Phys.org
  • #2
I believe Hawking radiation approximates a blackbody, so a black hole would emit a broad range of wavelengths which would change as it gains or loses mass.
 
  • Like
Likes newjerseyrunner
  • #3
Drakkith said:
I believe Hawking radiation approximates a blackbody, so a black hole would emit a broad range of wavelengths which would change as it gains or loses mass.
That is my understanding as well.
 
  • #4
  • Like
Likes newjerseyrunner

1. Are black holes actually black?

Yes, black holes are actually black. This is because they have an incredibly strong gravitational pull that even light cannot escape from, making them invisible to our eyes.

2. Do black holes emit any light?

Black holes do not emit any light themselves, but they can be detected through the radiation emitted by matter falling into them, known as accretion disks.

3. Can black holes appear in different colors?

No, black holes do not have a physical surface that can reflect light, so they cannot have different colors. However, the accretion disk surrounding a black hole can appear in different colors due to the different temperatures of the gas and dust particles within it.

4. Are black holes monochromatic?

Yes, black holes are considered to be monochromatic as they do not emit any visible light. However, they can emit different types of radiation such as X-rays and gamma rays.

5. Is it possible for a black hole to be white?

No, it is not possible for a black hole to be white. The term "black hole" refers to the fact that they do not emit any visible light, not the actual color of the object. Additionally, the intense gravitational pull of a black hole would prevent it from reflecting any light, making it impossible for it to appear white.

Similar threads

  • Astronomy and Astrophysics
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
2K
  • Cosmology
Replies
11
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
2K
Replies
6
Views
2K
  • Beyond the Standard Models
Replies
3
Views
2K
  • Astronomy and Astrophysics
Replies
12
Views
3K
  • Astronomy and Astrophysics
Replies
30
Views
4K
  • Quantum Physics
Replies
11
Views
1K
  • Special and General Relativity
Replies
2
Views
803
Back
Top