Don't black holes still only exist in theory?

Question

What evidence proves that they don't exist though?

Answer 1

Nope....black holes exist....lots and lots of them...

Answer 2

It is true that black holes are still theoretical and astronomers have not made any direct observations of them! However, there exists some convincing evidence for their existence. Wikipedia comments,'Most accretion disks and gas jets are not clear proof that a stellar-mass black hole is present, because other massive, ultra-dense objects such as neutron stars and white dwarfs cause accretion disks and gas jets to form and to behave in the same ways as those around black holes. But they can often help by telling astronomers where it might be worth looking for a black hole.

On the other hand, extremely large accretion disks and gas jets may be good evidence for the presence of supermassive black holes, because as far as we know any mass large enough to power these phenomena must be a black hole.



A "Quasar" Black Hole.Steady X-ray and gamma ray emissions also do not prove that a black hole is present, but can tell astronomers where it might be worth looking for one - and they have the advantage that they pass fairly easily through nebulae and gas clouds.

But strong, irregular emissions of X-rays, gamma rays and other electromagnetic radiation can help to prove that a massive, ultra-dense object is not a black hole, so that "black hole hunters" can move on to some other object. Neutron stars and other very dense stars have surfaces, and matter colliding with the surface at a high percentage of the speed of light will produce intense flares of radiation at irregular intervals. Black holes have no material surface, so the absence of irregular flares round a massive, ultra-dense object suggests that there is a good chance of finding a black hole there.

Intense but one-time gamma ray bursts (GRBs) may signal the birth of "new" black holes, because astrophysicists think that GRBs are caused either by the gravitational collapse of giant stars or by collisions between neutron stars, and both types of event involve sufficient mass and pressure to produce black holes. But it appears that a collision between a neutron star and a black hole can also cause a GRB, so a GRB is not proof that a "new" black hole has been formed. All known GRBs come from outside our own galaxy, and most come from billions of light years away so the black holes associated with them are actually billions of years old.

Some astrophysicists believe that some ultraluminous X-ray sources may be the accretion disks of intermediate-mass black holes.

Quasars are thought to be the accretion disks of supermassive black holes, since no other known object is powerful enough to produce such strong emissions. Quasars produce strong emission across the electromagnetic spectrum, including UV, X-rays and gamma-rays and are visible at tremendous distances due to their high luminosity. Between 5 and 25% of quasars are "radio loud," so called because of their powerful radio emission.'

Wikipedia further adds,'... According to the American Astronomical Society, every large galaxy has a supermassive black hole at its center. The black hole’s mass is proportional to the mass of the host galaxy, suggesting that the two are linked very closely. The Hubble and ground-based telescopes in Hawaii were used in a large survey of galaxies.

For decades, astronomers have used the term "active galaxy" to describe galaxies with unusual characteristics, such as unusual spectral line emission and very strong radio emission. However, theoretical and observational studies have shown that the active galactic nuclei (AGN) in these galaxies may contain supermassive black holes. The models of these AGN consist of a central black hole that may be millions or billions of times more massive than the Sun; a disk of gas and dust called an accretion disk; and two jets that are perpendicular to the accretion disk.

Although supermassive black holes are expected to be found in most AGN, only some galaxies' nuclei have been more carefully studied in attempts to both identify and measure the actual masses of the central supermassive black hole candidates. Some of the most notable galaxies with supermassive black hole candidates include the Andromeda Galaxy, M32, M87, NGC 3115, NGC 3377, NGC 4258, and the Sombrero Galaxy.

Astronomers are confident that our own Milky Way galaxy has a supermassive black hole at its center, in a region called Sagittarius A*:

A star called S2 (star) follows an elliptical orbit with a period of 15.2 years and a pericenter (closest) distance of 17 light hours from the central object.

The first estimates indicated that the central object contains 2.6M (2.6 million) solar masses and has a radius of less than 17 light hours. Only a black hole can contain such a vast mass in such a small volume.

Further observations strengthened the case for a black hole, by showing that the central object's mass is about 3.7M solar masses and its radius no more than 6.25 light-hours.'

Sorry about the heavy use of quotes!

Answer 3

yes. nobody can prove them just hypotheses based on observations.

Answer 4

black holes surely exist.. they have been proven in mathematical equations from Einstein, and also other scientist. They have never directly observed a black hole because... well its black... it sucks up the light that interacts with it.

But we do know that they are there because of the gravitation pull of stars in the middle of our own galaxy and others.. they interact with an invisible body very abruptly, so much so that it would like millions of suns at the same spot to recreate the effects.

They have founds that nearly all galaxy's have this same thing in the heart of it... so this has led scientist to believe that they are an essential part of the formation of a galaxy.

With discovery's like this we have slowly over roughly 500-1000years(a guess)gone from a beautifully organized, elegant, and relatively small universe to this huge, dynamic, and, chaotic universe we know today.  

Answer 5

Black holes have been observed in the universe.

Also it is impossible to prove a negative.

Answer 6

we can see them under some circumstances

http://en.wikipedia.org/wiki/Gravitation...

Answer 7

Black holes exist in theory in the same sense that atoms only exist in atomic theory. We've never observed an atom directly, because it is impossible, the same is true of black holes. However, it is possible to infer the existence of both through empirical evidence and abstract mathematical conclusion (this is true more of black holes).

In the scientific community, no one disputes the existence of black holes, at least not any serious scientist.

Answer 8

Actually, there is enough proof for black holes that very few scientists don't believe in them. An example of this proof is the star Cygnus X-1, which is a star that appears to be orbiting...nothing. this gives support to the idea that it is spiraling around a black hole. Also, the hole sucks light from the star, creating a visible disk around itself.

Answer 9

You can't prove something doesn't exist.  But we've observed things that can only be attributed to a small, compact, extremely massive source - things like the inner rotation curves of galaxies, mass distributions, gravitational lensing, and jets.

Answer 10

A common misperception outside the scientific community is the word "theory."  For example, Einstein's general relativity is just a theory.  This sort of phrasing implies that it's probably wrong.  But in science "theory" is the same as "law."  We have shown that general relativity works, we have evidence.  The idea that a bunch of math could equate to physical reality sometimes eludes people, and I will admit that some things that are mathematically possible are not physical.  Other times, we have math showing a possibility before we can devise an experiment to test whether or not it's physically observed.

Now, onto your question, we have enough physical evidence to show that virtually every galaxy has a black hole at its center.  Our galaxy, the Milky Way, has a black hole.  

This is sufficient evidence for the "theory" of black holes to be physical law.  At that point, all evidence which purports to suggest they don't exist (perhaps they are really just something else, or that the experiment was setup incorrectly, etc.) is incorrect.  This is similar to someone showing a video of a ball that they take the mass of, measure, then show floating away up into the sky.  We can show from the mass and measurement what the density is -- compare this to air.  Surely if it is denser than air it will drop, not float.  Then, without explaining how they got the ball to float away, we know the video is false and the experiment conducted was flawed.  Whether it was a faulty scale, ruler, and whether it was a helium balloon, they attached a wire, or even filmed it upside down, we don't have to say, we know from previous laws that the experiment is incorrect.