Astronomers have discovered a small black hole at the center of a dense star cluster, a region not typically associated as friendly to black holes
Astronomers have discovered a small black hole at the center of a compact star cluster, a region not typically associated as friendly to black holes. The mass of the black hole is 10 times that of the Sun. It was discovered in a globular cluster in the elliptical galaxy NGC 4472, which is about 50 million light-years from Earth in the Virgo cluster. A black hole is an object whose mass is so concentrated that nothing, including light, can escape its gravitational pull, up to a certain distance. The discovery, detailed in the Jan. 4 issue of the journal Nature, is surprising because some theories predict that the gravitational interactions of black holes inside clusters would simply kick the black hole out of the cluster.
The scientists believe that the kicking process works in the following way: because black stars are usually among the most massive objects in the globular cluster, they sink to the center of the cluster. Then they become part of a double star with another star or black hole that has also rolled into the center of the cluster. A binary system made of a black hole and another star can be stable, but when two black holes come together, the gravitational interactions between them can cause one or both of them to fly away.
The fact that the black hole in NGC 4472 escaped its fate may indicate that it is friends with a star, rather than another black hole, the researchers say. "From simulations we conducted on computers, it appears that it is difficult to keep black holes inside clusters, and usually they fly away due to the fact that it is a double system of black holes. said the lead researcher, Thomas Maccarone (Maccarone) from the University of Southampton in the UK.
There is another way by which a black hole can remain in a cluster - there are contracts that in some cases it will be possible to start with a massive black hole - that is, one with a mass of at least 50 suns. If this happens, the flying scenario does not work. According to him, the black hole may eventually merge with all the smaller black holes until a black hole with a mass of a thousand times the sun is built. It's hard to move black holes at such masses, McCaruna says.
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Roy:
When we talk about the size of a black hole - we talk about the size of its event horizon - that is, the area where the person who passes through it will no longer be able to get out - even if it is a photon.
A simple black guy (one that does not rotate and is not charged) The event horizon is the shell of a sphere whose radius is obtained from the mass by calculation and is called the Schwarzschild radius (not Schwarzfield) after the Jew who first found this solution to the system of equations of general relativity.
Spinning holes "look" a bit different (they are flattened like wheat) and their shape has been calculated by other people (like Kerr).
The Schwarzschild radius is easy to calculate.
A black hole with the mass of the sun will have a radius of 3 km.
The radius of the black hole increases in direct proportion to the mass - that is - a black hole whose mass is ten times the mass of the sun will have a radius of 30 km.
You can expand your understanding of the matter here:
http://en.wikipedia.org/wiki/Schwarzschild_radius
Nothing can escape from a black hole - including light.
It is hypothesized that near the envelope of a black hole radiation is created in a process that at the same time also sends negative energy into the black hole and thus causes it to dissipate over time.
It's not radiation coming out of the black hole, but the result is reasonable.
It is advisable to know that the existence of this radiation has not yet been verified by experiment/measurement.
This radiation is called "Hawking radiation" and sometimes also "Beckenstein Hawking radiation" after the Israeli physicist Jacob Beckenstein whose diagnoses helped Hawking reach a conclusion about its existence.
Read more here:
http://en.wikipedia.org/wiki/Hawking_radiation
In general, this claim is indeed true. To the point of "Hawking radiation", which is apparently emitted from the black hole after all, although this has not yet been observed, of course.
Regarding the size of a black hole, there are two sizes that may answer your question.
1. The actual size of the mass it holds, in this case it is customary to refer to the black hole as a "singularity" - because the black hole is a point, for that matter of zero size, where the mass is concentrated. I think that once a star collapses the black hole has no physical limit on the density and therefore There is nothing that prevents it from shrinking to a point, in contrast to the example of a neutron star whose minimum radius is defined by the limit of the possible density for neutrons according to one or another physical law.
2. The second size that may answer your question is known as the "Schwartzfield radius", this is not the size that the mass occupies, but the radius from which nothing else is emitted. Also known as the "event horizon" of the black hole. This radius depends on the mass and can also be calculated using Newtonian mechanics. You can find numbers on Wikipedia under the name "Blackfield Radius"
Summarize = Summarize, at least that's how it seems to me... but I'm also dyslexic 🙂
I am not disputing what is written above, but with my interest in TV programs I have seen
Astronomers say that light itself is also trapped inside the black hole and cannot escape. So I wanted to know if this claim is true.
And if I may ask, what is the relationship between the size of a black hole and its mass?
Black holes do emit light just like any star
Since the time ratio in a black guy is different from our time ratio
Due to the huge mass, time there passes much more slowly
Every day there can be like hundreds of years with us.
And if we point a camera at the black hole for hundreds of years in a row we can see emissions of light at fixed times every few years there will be an emission of light.
I have a question... what happens when two black holes are close to merging? Does the space-time between them stretch or shrink and how does the merger happen in general?
Thanks to those who answered... [=