Astronomer Discovers Upper Mass Limit for Black Holes

this paves a way for new thought that we might calculate the safety for our planet from the data which we get about the size of the black hole at the center of our very galaxy !
hats off to you for the path breaking research !

Was this upper limit found via observation or mathematically?

Are they sure the upper limit isn't an upper limit of the way we are observing the black hole?

(Kinda like saying after it goes black, we reached the upper limit of 'visibly' observing the star)

It appears that they're just saying that they can get so large that they prevent other objects from forming near them, so nothing to "eat". But I doubt that you say this is a true upper limit, just a practical one.

A true upper limit would be where the black hole's force is in equilibrium with spacetime, to the point that the amount of mass required to grow an extra inch wouldn't be worth it. At that point, it stays in its hole.

If its density is finite won't it eventually fill up to its own event horizon? There would simply be no more room inside the horizon for additional mass. Perhaps infinite density is not possible.

If its density is finite won't it eventually fill up to its own event horizon? There would simply be no more room inside the horizon for additional mass. Perhaps infinite density is not possible.

I've wondered about this as well. Does the black hole fill up and if so, once matter breaches the event horizon does the black hole explode?
(big bang?)

I would expect the event horizon to expand at some proportional rate to the increase in mass of the black hole.

If its density is finite won't it eventually fill up to its own event horizon? There would simply be no more room inside the horizon for additional mass. Perhaps infinite density is not possible.

No, because as the black hole absorbs matter, its event horizon expands in proportion to its mass. This expansion is such that as time goes on, the average density of a black hole becomes lower, not higher. If a black hole eats enough, you eventually reach the point where the density is so low that it would float on a big enough ocean, if it had a surface that somehow prevented the ocean from just being eaten.

Accourding to this site, there's already a 18 billion sun mass black hole
http://space.news...red.html

If its density is finite won't it eventually fill up to its own event horizon? There would simply be no more room inside the horizon for additional mass. Perhaps infinite density is not possible.

The radius of the event horizon of a (Schwartzchild) black hole is GM/c^2, with increase in mass teh event horizon also increases in size. And most importantly, inside the event horizon spatial dimensions become timelike (and vice versa, the time dimension becomes spacelike), which implies that inside the event horizon, one can not move back in space (just as outside the event horizon, in the spacetime in which we exist, we things can't progress back in time), so all the mass will eventually be pulled into the singularity, which is the centre of the black hole.

The problem of Schwartzchild, it's steady-state solution, it doesn't care, how much of time it requires for its establishing. From AWT follows, the mass larger then five millions of sun mass cannot be achieved during Universe life by simple accretion, so if some massive holes exists, they should be formed by another mechanism.

The common black hole is "black" because of giant vacuum density gradient, which is behaving like glass sphere or semitransparent mirror due the total reflection phenomena near the event horizon. The larger the black hole is, the larger is curvature of space around it. But every space-time curvature has its own energy density by Einstein field equations, and such energy density is equivalent to additional matter density of vacuum due the E=MC^2 equivalence. This dense vacuum is surrounding black hole and it's balancing its internal mass density by such way, it decreasing surface density gradient.

If the black hole become sufficiently large, then the mass density of vacuum above black hole will compensate the mass density below event horizon, so only subtle density gradient can appear here. Therefore the vacuum density gradient will not reflect the energy from inside anymore and whole the object will change into giant glowing star, emanating both energy, both matter from inside, so called the quasar. We can compare the negative capillary waves of the sink model, which are getting faster for shorter wavelength, so they can penetrate the event horizon as well. The similar conclusion results from Yilmaz and Heim theories, you can find some transparent derivation for example here: http://arxiv.org/...1110.pdf

By Aether Wave Theory most of sufficiently large galaxies inside of our Universe were created by evaporation of quasars, and the Milky Way is no exception. The black hole siting at the center of most of galaxies is supposedly a cold remnant of quasar, which has evaporated the excessive matter. This is because only black holes larger then certain mass limit can evaporate their matter by the above mechanism.

Here are many other, less technical reasons, why the size of BH should be limited. For example, the pressure of acrettion radiation keeps a lot of matter at distance, whenever the black hole becomes larger (a sort of Leidenfrost effect).

http://en.wikiped...t_effect

An upper mass limit for black holes? Imagine the following scenario: Two black holes, of masses approaching a mass limit (of arbitrary size) are orbiting each other and slowly falling into each other. When these two monster black holes merge, wouldn't their combined mass will greatly exceed the defined mass limit?

Perhaps the apparent upper bound we observe is related to the density of the primordial universe. In other words, there was only so much stuff to create the black hole. Once you run out of stuff it is impossible for the black hole to become larger. Thus, the density of the early universe could be directly related to the maximum size of a black hole we see today.

"Here are many other, less technical reasons, why the size of BH should be limited. For example, the pressure of acrettion radiation keeps a lot of matter at distance, whenever the black hole becomes larger (a sort of Leidenfrost effect)."

Did you read the article? Why re-state it? Or is this website a billboard for your hilarious theories?

...When these two monster black holes merge, wouldn't their combined mass will greatly exceed the defined mass limit?..

By AWT such BH would behave like pair of mercury droplets, due their surface energy. Briefly speaking, the merging of such curved spacetimes requires the temporal formation of thin neck with negative curvature, which is the source of strong repulsive force.

It means, the merging of such black holes is possible, but it requires a substantial time. And if it occurs at the end, it's followed by releasing a substantial energy in the form of gamma ray flash - a much higher, then the current relativity based field theory assumes. By such way, AWT explains a mysterium of ultrashort gamma ray flashes, which are so intesive, so they can travel through whole universe. http://en.wikiped...stronomy

..Or is this website a billboard for your hilarious theories?..

Why hilarious? I discussed a black hole mass limit and its consequences here before a two years already. Now it was just a confirmed.

http://www.physfo...pic=8904

Was this upper limit found via observation or mathematically?

This is an observational result. Note the apparent absence of medium-class black holes in this distribution. Albeit it be explained by other ways, such discrepancy supports my theory as well.

http://arxivblog....oles.jpg

It's all just about thinking and good knowledge of experimental results. If somebody doesn't know these results, it can consider my theories hilarious - but it's not my problem, indeed.