# If blackholes collapse under there own gravity , then what it means that gravity is a property of spacetime?

what role the fabric of spacetime plays in contracting or collapsing the star to become a blackhole or if a super massive star collapse only due to its own gravity?General relativity says gravitation is an acceleration which a body receives due to curvature of spacetime ,if it means there is no gravitational force but its just the distortion of spacetime?

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• Esper
Lv 5
7 years ago

Dear Bigbang P,

You are exactly right.

As the mass collapses it continues to create a “deeper” warping of the space/time, until eventually that ”well” becomes deep enough to form the event-horizon, and becomes a blackhole.

Live long and prosper _\\//

ESP

• Anonymous
7 years ago

"If blackholes collapse under there own gravity,"

They don't, but stars do.

"then what it means that gravity is a property of spacetime?"

It means that gravity is how spacetime curves, its shape, the shape of the geodesics that can be formed "on" it.

"what role the fabric of spacetime plays in contracting or collapsing the star to become a blackhole"

The acceleration necessary to keep one neutron from collapsing "through" another neutron, cannot be provided by neutron degeneracy pressure.

"or if a super massive star collapse only due to its own gravity?"

Correct.

"General relativity says gravitation is an acceleration which a body receives due to curvature of spacetime,"

Right.

"if it means there is no gravitational force but its just the distortion of spacetime?"

You got it. If you let c go to infinity, then gravitation becomes Newton's gravitational force.

• 7 years ago

I'm not sure if I understand the question correctly, but I'll try to answer it.

First, please do not think of spacetime as a fabric, something tangible. It's just the dimensional frame of reference, and the many pictures with a large body distorting it are just visualizations to make it more accessible. It's difficult to describe distortions in four dimensions, so you'll usually see a distortion of a two dimensional grid or something. What a distortion of spacetime really means is that the spatial dimensions and time themselves are distorted ('uneven').

Now, gravity is a force. There are multiple ways to describe that same force, and one way is to use the model of distorted spacetime. A body with mass will create those curvatures, which in turn can affect other bodies with mass- this also applies to a body itself. That means a gravitational collapse is the result of distortions in spacetime the body itself causes.

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• neb
Lv 7
7 years ago

For the millionth time - MASS IS NOT THE ONLY THING THAT CAUSES GRAVITY.

Look at Einstein's field equations. The source of gravity is the energy-momentum tensor (also called the stress-energy tensor). It has 10 components, only one of which is rest mass. The other 9 components are for momentum, pressure, and stress in various directions. READ THE EQUATIONS BEFORE YOU ANSWER.

Sorry, but I'm sick of having to say that over and over.

As for your question, if you look at the curvature side of the Einstein's equation, they effectively describe how geodesics behave in a gravitational field. A geodesic is the shortest distance between two points on either a curved or flat surface. A geodesic on a flat surface is a straight line, a geodesic on a curved surface is a curved line. In either case , they represent force free paths - objects will follow those paths unless some other force acts on them to divert them from the geodesic. Einstein specified that the behavior of neighboring geodesics were such that they moved closer and closer to each other the deeper you went into a gravitational field (unlike parallel straight lines on a flat surface, initially parallel geodesics in curved space can converge). This effectively produces a volume reduction of space-time the deeper you go into a gravitational field (that is why the center of a black hole has zero volume). So, in the presence of a gravitational field, everything tries to follow "force-free" geodesics. Of course they eventually are blocked from their geodesic (like an apple is blocked when it hits the ground). Whatever is blocking them has to exert a pressure in order to block it. When a black hole forms, matter can no longer generate the pressure to resist things trying to follow there geodesics, so they follow them to their merry end - the zero volume center where all geodesics converge at the same place (also commonly know as the singularity)

• 7 years ago

Wow. That's a lot of good questions mixed up with a lot of bad assumptions and misunderstanding.

1. Black holes don't collapse. The cores of very large stars can collapse and become a black hole.

2. Newton's Laws describe acceleration, including gravitational acceleration, not Einstein's theory of relativity.

3. Energy is transferred by subatomic particles called Bosons (e.x. photons, gluons, gravitons)

4. Electromagnetic energy is radiated from a body in the form or photons, traveling at the speed of light.

5. Gravitons do not radiate from there source (anything with mass) but instead affect the nature of space time in the vicinity of the mass. The mass energy is stored in this deformation. Other mass is affected by this distortion, and as it approaches the first mass, energy is transferred instantaneously from the space time distortion to the approaching mass. Prorogation of this energy transfer will then advance through space time like a domino affect until it reaches the mass that's the source of the distortion. These distortions are sometime depicted as different sized balls making depressions on an elastic sheet.

• John W
Lv 7
7 years ago

What's the effect of a conveyor belt on a carton of milk riding on it. That's the effect of the fabric of spacetime in contracting or collapsing a star to become a blackhole. Think of it as a bunch of marbles on a flexible fabric all rolling into one spot as they deform the fabric.

• fiorot
Lv 4
4 years ago

It is not relatively fairly like that. First there used to be a disk of gas and dust across the sun. Regularly, the disk developed little clumps of bigger concentrations of gasoline and dirt, and thanks to the drive of gravity, these attracted increasingly neighborhood fabric into themselves except they fashioned planets and moons. That is the collapsing bit - the give way of a dust and gas cloud into concentrations, within the type of planets and moons. The query of the roughly spherical shape is reasonably separate. The cave in of the dust and gasoline produced far more non-rounded bodies (asteroids, for illustration, and the smaller moons) than quasi-spherical ones. In each of those bodies, circular or in any other case, two forces were combating it out for supremacy. One used to be self-gravity, the force exerted via every grain of dust within the object on each different one. Seeing that gravity relies on mass and the distance between the attracting our bodies, extra tremendous bodies had higher self-gravity. This self-gravity tended to make them spherical (within the absence of rotation). The intent for that in flip which you could suppose of as being abilities energy. For something to be far from the centre of the physique, it have got to have quite a few skills vigour. You know that from picking out things up here on the earth. You ought to exert a force on the thing to be capable to opt for it up against the force of gravity. By way of doing work on the object in picking it up, you supply it expertise energy. For those who let go, it offers again that advantage vigour, through falling. The competencies vigor of the entire factor is at a minimum (which is the steady crisis) when every art is as close to the centre of gravity as it may possibly get. That seems to be a sphere. The drive working the other way is the rigidity of the material of which the planets are made. If you squeeze rocks just a bit, as you already know, nothing happens. However if you squeeze them a first-rate deal, because it maybe below countless numbers of miles of alternative rocks, they will behave extra like putty than the rocks we know. So, if there is best a little bit gravity, the rigidiy of the rocks wins. If there's tons (i.E. Of the moon or planet is gigantic sufficient) then gravity wins, and the item becomes relatively spherical.

• Sagim
Lv 6
7 years ago

It's possible to justify gravity as property of curvature of the fabric of spacetime, but as a property spacetime, it would be like a premature conjecture.

• 7 years ago

It may be only a distortion of space-time but it still conveys energy from one point to another. Namely gravitational potential energy. What does the electromagnetic force do? it conveys energy. So does the strong and weak nuclear force. At the quantum level, they do so by means of force carriers, i.e. bosons. Gravitons cannot yet be detected but they must exist according to quantum physics. In short, we don't know what causes these forces but anything that represents a transfer of energy from one point to another is a force. Gravity is one of them.

• 7 years ago

Mass is required for gravity. Think of it like this, you get a trampoline and put a couple marbles all over it. You, a person would have way more effect on the trampoline and the marbles than, say, a cat.