How Can We Determine the Size of a Black Hole?

  • Thread starter Thread starter fillipeano
  • Start date Start date
  • Tags Tags
    Black hole Hole
AI Thread Summary
The size of a black hole is theoretically determined from its mass, with the event horizon being a key measurement. For example, one solar mass corresponds to a diameter of approximately 5.9 kilometers. Actual measurements of black hole diameters are currently lacking, but future observations, particularly of the Milky Way's central black hole, may provide data within the next decade. It's important to note that the event horizon is an effect of the black hole, while the singularity itself has no physical size. Various theories exist regarding black hole interiors, leading to different interpretations of their characteristics.
fillipeano
Messages
51
Reaction score
0
Is there any way to determine how big a black hole is? I googled the question but I didn't find any answer.
 
Astronomy news on Phys.org
If you mean its diameter, you can determine it theoretically from its mass:
1 solar mass = 5.9 km,
1000 solar masses = 5900 km and so on.
AFAIK, there are no actual measurements of a diameter. Maybe within the next 10 years, they will have measurements of the BH in the center of the Milky Way.
 
Black hole size is usually expressed as the size of its event horizon, which is pretty easy to calculate.
 
yes, but it should be noted that the EH is an effect caused by the BH. the actual BH itself has no size, ie, the singularity proper has zero volume.
 
jnorman said:
yes, but it should be noted that the EH is an effect caused by the BH. the actual BH itself has no size, ie, the singularity proper has zero volume.

That's only if a certain picture of black hole interiors is correct. Several different theories are available with quite different outcomes. Thus the event horizon is the boundary as far as we know or close to.
 
Last edited:

Thread 'Our Beautiful Universe - Photos and Videos'

This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
View full post »

Thread 'Asteroid 2024 YR4 has a 1% risk of a multi-megaton impact in 2032 (now ruled out)'

Asteroid, Data - 1.2% risk of an impact on December 22, 2032. The estimated diameter is 55 m and an impact would likely release an energy of 8 megatons of TNT equivalent, although these numbers have a large uncertainty - it could also be 1 or 100 megatons. Currently the object has level 3 on the Torino scale, the second-highest ever (after Apophis) and only the third object to exceed level 1. Most likely it will miss, and if it hits then most likely it'll hit an ocean and be harmless, but...
View full post »

Similar threads

B Black hole equivalence
Replies
20
Views
2K
B Confusion regarding black hole spin
Replies
40
Views
3K
B I Need Help on Understanding Some Basic Astrophysics / Sand Clock Universe
Replies
5
Views
2K
I Can there be slowly-falling accretion disks in black holes?
Replies
11
Views
2K
I Light curving around vortex simulating a black hole
Replies
5
Views
2K
I Amount of black hole entropy inside the Universe?
Replies
5
Views
2K
I The initial density of an object and its compression into a black hole
Replies
17
Views
4K
Stargazing Dark matter and its effect on the orbit of stars
Replies
13
Views
3K
B Ultramassive Black Hole (UMB), 30 billion solar masses?
Replies
4
Views
2K
I Early Universe massive Black Holes question
Replies
10
Views
3K

Hot Threads

Recent Insights

Back
Top