Why would a black hole grow in size???

originally posted by: Vector99

originally posted by: TheMadTitan

originally posted by: 3daysgone
a reply to: TheMadTitan

0.1% in the grand scheme of things.

I think you have have greatly overestimated the intelligence of mankind.

Why would religion explain it easily?

Twas merely a guess, you are correct though, an overestimation of our species intelligence denotes a sense of arrogance, no? We think we are smart, tis a drop in the ocean. Curiosity besets me, what would you have us at, 0.00001%, I think, is still generous?

In perspective of life on earth?

We are an anomaly, something religion can explain easily, so long as you don't ask questions.

Water is a key factor, any planet that can sustain liquid water can sustain life.

Mars is a possibility, but we have to teraform it, and we do not have that tech available. At least publicly.

Why would religion explain it easily? Why would you not ask questions for such a huge claim? I honestly don't know why you would bring religion into a thread based in Physics?

a reply to: TheMadTitan
Religion explains it easily with god.

I personally don't subscribe to the god theory, but basically god is how religion easily explains it.

Is there a god? Maybe.

Were we created? Maybe.

Are we a product of time and the natural tendency of life to further itself?
Probably.

a reply to: Golantrevize

OK first to understand what happens you have to understand the inverse square law.The gravitational attraction force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation distance. The last part here is what's important if I have two objects a black hole allows our to objects to get close then would be possible under normal circumstances because one of the masses is compressed in to a smaller space.

If I replaced our sun with a black hole the size of a golf ball it's gravity would be unchanged. Planets would still orbit just as if nothing had changed. But now I can get alot closer to the center of gravity to the point where I will hit a point where light cannot escape. This point never really changes no matter the size but now there is something I can do add energy in the form of momentum. This will change where the horizon seems to be. Think of a drill grabbing a cloth how it pulls the corners in towards the drill bit creating a curved path that leads to the drill. This means that light for example will travel a curved path many of which will lead to the black hole making it look like the event horrizon has changed.

So to answer your question adding mass to a black hole doesn't change the event horizon it changes the paths that lead to it.

a reply to: dragonridr

once we figure out how gravity works, maybe then we can further that education.

a reply to: Golantrevize
I think that is just a scientific way of stating that they are not entirely sure, but they may have an idea.

Its gravity is getting bigger while it stays the same size. But then again, at what point does it start sucking in gravity as well? Like it does light? But then again what is gravity anyways? And how can it suck in something that supposedly does not have a mass?

Its one of those questions you will never know till your there and trying it, seeing it with your own eyes to sort of say.

You know kind of like how many licks does it take to get to the bottom of a tootsi pop? The world may never know. Your asking a subjective question, on an objective subject. It is a conundrum.

originally posted by: LightSpeedDriver
a reply to: Golantrevize

My totally uneducated guess would be that the black hole is absorbing more matter (light, dust, planets, stars) than it can emit in the form of Hawking radiation. What goes in must come out, to use an old adage. Again, just a wild stab in the black hole...I mean dark.

ETA Hawking radiation

Susskind put the Hawking Radiation to rest.

originally posted by: Gothmog
The more mass , the more gravity. The more gravity , the larger the event horizon becomes as the time/space fabric is warped.

For some posting on here
Not only does physics account for how a Black Hole (gravity well ) is created , they have proof of their existence.
Black Holes were even postulated to exist well before Einstein.

The theory still has some "holes" in it. Does it ever release the material, or does it keep building until everything is sucked in? Otherwise, I think a lot of us understand it the way you do. We may be looking at a portal to another side of the universe or it goes to another dimension.

originally posted by: galadofwarthethird
a reply to: Golantrevize
I think that is just a scientific way of stating that they are not entirely sure, but they may have an idea.

Its gravity is getting bigger while it stays the same size. But then again, at what point does it start sucking in gravity as well? Like it does light? But then again what is gravity anyways? And how can it suck in something that supposedly does not have a mass?

Its one of those questions you will never know till your there and trying it, seeing it with your own eyes to sort of say.

You know kind of like how many licks does it take to get to the bottom of a tootsi pop? The world may never know. Your asking a subjective question, on an objective subject. It is a conundrum.

It is gravity .
Mass = gravity

originally posted by: Justoneman

originally posted by: Gothmog
The more mass , the more gravity. The more gravity , the larger the event horizon becomes as the time/space fabric is warped.

For some posting on here
Not only does physics account for how a Black Hole (gravity well ) is created , they have proof of their existence.
Black Holes were even postulated to exist well before Einstein.

The theory still has some "holes" in it. Does it ever release the material, or does it keep building until everything is sucked in? Otherwise, I think a lot of us understand it the way you do. We may be looking at a portal to another side of the universe or it goes to another dimension.

Black Holes do emit some radiation in a tremendous burst that is commonly known as "belches"
And , Black Holes can recede and fade away just as well as growing in size.
Most do.

originally posted by: Vector99
a reply to: dragonridr

once we figure out how gravity works, maybe then we can further that education.

What is left to figure out how it works ?
Or did you mean the basis for gravity such as the "god particle" is what causes mass ? And in effect leads from there to gravity ?

originally posted by: Gothmog

originally posted by: galadofwarthethird
a reply to: Golantrevize
I think that is just a scientific way of stating that they are not entirely sure, but they may have an idea.

Its gravity is getting bigger while it stays the same size. But then again, at what point does it start sucking in gravity as well? Like it does light? But then again what is gravity anyways? And how can it suck in something that supposedly does not have a mass?

Its one of those questions you will never know till your there and trying it, seeing it with your own eyes to sort of say.

You know kind of like how many licks does it take to get to the bottom of a tootsi pop? The world may never know. Your asking a subjective question, on an objective subject. It is a conundrum.

It is gravity .
Mass = gravity

and

1/2Mass x Velocity Squared = Kinetic potential.

mass:

"With the advent of the special theory of relativity by Einstein in 1905, the notion of mass underwent a radical revision. Mass lost its absoluteness. The mass of an object was seen to be equivalent to energy, to be interconvertible with energy, and to increase significantly at exceedingly high speeds near that of light (about 3 × 108 metres per second, or 186,000 miles per second). The total energy of an object was understood to comprise its rest mass as well as its increase of mass caused by high speed. The rest mass of an atomic nucleus was discovered to be measurably smaller than the sum of the rest masses of its constituent neutrons and protons. Mass was no longer considered constant, or unchangeable. In both chemical and nuclear reactions, some conversion between mass and energy occurs, so that the products generally have smaller or greater mass than the reactants. The difference in mass is so slight for ordinary chemical reactions that mass conservation may be invoked as a practical principle for predicting the mass of products. Mass conservation is invalid, however, for the behaviour of masses actively involved in nuclear reactors, in particle accelerators, and in the thermonuclear reactions in the Sun and stars. The new conservation principle is the conservation of mass-energy."

a reply to: Golantrevize

Why would a black hole grow in size???

It doesn't. It becomes more dense.

IOW, has more mass, exerts more gravitational influence. Apparently they are too 'small' to resolve with our current instruments. The little computer enhanced 'video' we have of the one at the center of our galaxy shows us they are... invisible.

Maybe the new James Webb telescope , due to launch sometime next year, will give us a closer look.

a reply to: Justoneman

Who was speaking Kinetic Energy ?

a reply to: Gothmog

And , Black Holes can recede and fade away just as well as growing in size.
Most do.

Maybe they explode like suns do, maybe Quasars are the Super Novae of Black Holes.

I doubt they fade away, more like they eat everything around and wander off, drifting silently about, invisible to our instrumentation. The Universe might be filled with dark, stable monstrosities, this could explain theories of missing matter.

originally posted by: dragonridr
a reply to: Golantrevize

If I replaced our sun with a black hole the size of a golf ball it's gravity would be unchanged. Planets would still orbit just as if nothing had changed. But now I can get alot closer to the center of gravity to the point where I will hit a point where light cannot escape. This point never really changes no matter the size but now there is something I can do add energy in the form of momentum. This will change where the horizon seems to be. Think of a drill grabbing a cloth how it pulls the corners in towards the drill bit creating a curved path that leads to the drill. This means that light for example will travel a curved path many of which will lead to the black hole making it look like the event horrizon has changed.

So to answer your question adding mass to a black hole doesn't change the event horizon it changes the paths that lead to it.

Some of that is true but your last sentence sounds wrong. Adding mass to a black hole does change the radius of the event horizon which is at the Schwarzchild radius, which for a non-rotating black hole would be:

r=2GM/c^2

where
r is the Schwarzchild radius
G is the gravitational constant
M is the mass
c is the speed of light

So as mass increases, so does the Schwarzchild radius, where the event horizon is located, and according to this formula the Schwarzchild radius of the sun is about 3km. I guess you say golf ball because it's smaller than 3km but a solar mass in any size less than about 3km is a black hole.

While relativity predicts infinite density, this is usually seen as a breakdown of the theory, and it's why theoretical physicists are trying to develop a quantum theory of gravity, that would make more accurate predictions about the density than relativity does. So in other words to answer the OP's question, it's probably not infinite density but some kind of as yet not understood quantum phenomenon. We can of course make calculations of average density inside the Schwarzchild radius, but the actual density profile isn't known without a quantum theory of gravity.

When you factor in angular momentum, this changes the shape of the event horizon from the spherical shape described by the Schwarzchild radius to a more complicated object described by the Kerr metric, but this is an extra complication not in the original question which I think is more likely to confuse the person asking rather than answer their question.

originally posted by: intrptr
a reply to: Gothmog

And , Black Holes can recede and fade away just as well as growing in size.
Most do.

Maybe they explode like suns do, maybe Quasars are the Super Novae of Black Holes.

I doubt they fade away, more like they eat everything around and wander off, drifting silently about, invisible to our instrumentation. The Universe might be filled with dark, stable monstrosities, this could explain theories of missing matter.

The "missing matter" is most likely dark matter
I only put the part about "fading away" in there as it is one common theory today . Kind of like the "micro-miniature" black holes created by the LHC fade away in less time than 1/1000000000 of the time it takes to blink an eye.

And , probably , a black hole cannot explode. They could only implode over time.

Great thread...
Have read all the physicists works from Hawking to Susskind , Wheeler , Polchinski , etc.
Amazing stuff.
And , black holes may well be a figment of space/time imagination...if certain superstring theories are followed.
Thread for another day.

a reply to: Gothmog

The "missing matter" is most likely dark matter

Meaning invisible. Or interdimennsional. In the former, no one knows how massive black holes are, or how many.

In the latter, other dimensions have no mass, just energy.

And , probably , a black hole cannot explode. They could only implode over time.

Black holes emit, at the polls, called Jets.

Before you theorize, I am familiar. Jets are too energetic to be from feeding. If black holes emit at the poles they can explode too. Thanks for not explaining quasars.

a reply to: Golantrevize

One common misconception about Black Holes is that the gravity at the singularity must be infinite. It's not.

It's just very, very high.

Earth's escape velocity is around 11 km/second

Jupiter's escape velocity is around 59 km/second

The Sun's escape velocity is around 618 km/second.

A Black Hole's escape velocity exceeds 299,792 km/second.....which is why it would appear black, as light does not go fast enough to escape from it.

The Event Horizon is where that ends. Just outside the Event Horizon, you could orbit that Black Hole.

If the gravity of the Black Hole were infinite, it would accelerate mater to the speed of light instantly, which it does not.

In order for it to have infinite gravity, it would have to have the equivalent mass (infinite) and we know it does not because of the observations we've made of bodies orbiting about Black Holes (like the one at the center of our galaxy).

a reply to: eriktheawful

Infinite gravity would also equate to an infinite range, as gravity follows the inverse square law. The strength of gravity falls out at the inverse square of its distance. Therefore, if it were infinite, then its square root would also be infinite, and its effect would disrupt the universe.