How do black holes form and what cause them to be black???

Question

Thank you so much for your detailed answer...tom science

Answer 1

Black holes are thought to form from stars or other massive objects if and when they collapse from their own gravity to form an object whose density is infinite: in other words, a singularity. During most of a star's lifetime, nuclear fusion in the core generates electromagnetic radiation, including photons, the particles of light. This radiation exerts an outward pressure that exactly balances the inward pull of gravity caused by the star's mass.

As the nuclear fuel is exhausted, the outward forces of radiation diminish, allowing the gravitation to compress the star inward. The contraction of the core causes its temperature to rise and allows remaining nuclear material to be used as fuel. The star is saved from further collapse -- but only for a while.

Eventually, all possible nuclear fuel is used up and the core collapses. How far it collapses, into what kind of object, and at what rate, is determined by the star's final mass and the remaining outward pressure that the burnt-up nuclear residue (largely iron) can muster. If the star is sufficiently massive or compressible, it may collapse to a black hole. If it is less massive or made of stiffer material, its fate is different: it may become a white dwarf or a neutron star.

To know why they're considered "black" would mean understanding the meaning of "black" itself. Black is simply the absence of light. Something that is 100% purely black is an object that obsorbs ALL white light shining on it just such that none is reflected back to the eye. We see no color in that object because of the properties in that object's atoms that lead no part of white light to be reflected.

A black hole is black because of a slightly different reason. The graviational pull inward within it is so great that not even light can escape, so NO light whatsoever comes back to the observer. It is then impossible to "see" because our eyes are 100% dependent upon the reflection of light from an object to detect its color. No light reflection = no color, and thus, no sight of the object.

Now black things on earth are seen simply because of how their surroundings define them. If a black box were in front of a white background, it would be seen only because of the background. Because space is also black, there is no definition to indirectly detect the sight of a black hole.

Answer 2

They are black because nothing, not even light, is fast enough to escape. A black hole is formed when a star dies in a supernova. If it is above a certain critical threshold of size (mass) while the outer layers erupt off in an explosion (generating transuranian elements and those heavier than iron) the inner core is compressed by an implosion.

The effective density of a black hole may be infinite. It is no longer matter as such, it has become what is called a 'singularity' which means 'we don't know what it really is'.

This is somewhat of an oversimplification, but if you have been worrying about getting sucked into a black hole, for heaven's sake, stop. There are none within light years of us.

Answer 3

There are a few theories but, no one really knows for sure. So, be careful not to accept the most popular theory as fact.

What could exist that no light could escape from once it has entered it and try to engulf everything close to it including light?

The most popular theory would say, well we know that gravity draws things towards it. So, in order for a black hole to engulf and contain light it must have a lot of gravity. So, it must be more dense than anything we know off. What could this be a result of? We know that stars bend light, we think, because of their gravity. So, a black hole must be the result of a collapsed (imploded), or collapsing (imploding), star. However, we don't know what actually creates gravity.

An interesting, but unrelated, notation is that gravity bends light, so, it would be logical to assume that, however imperceptively, anything with gravity bends light. This would invalidate light as a unit of measurement for time and distance since it is getting bent all over the place as it passes every little piece of cosmic dust in the universe and any bend adds distance to a straight line. How do you know how far light has traveled and if you don't know how far it has traveled, you don't know how much time it took to get there.

Anyway, this thing about black holes is kinda like the Big Bang. The Big Bang says that something exploded or expanded and created the universe but, it doesn't say where the thing came from or what existed before the thing. If you ask them, they call you stupid and say anything before the Big Bang is before time and is meaningless and they're not going to talk about it. In the meantime, they run experiments and postulate theories to try to figure out how to create something outa nothing.

Time, of course, is now based on light, which any measurement of, is only valid in an absolute vacuum which does not exist and could only have existed in the time vacuum before the Big Bang.

Not to mention that we have black holes swallowing up entire galaxies which makes for a pretty dam big collapsing star.

Black holes may be the thing that creates gravity, whatever that is.

One thing that is occuring is that the idea of a vacuum is being considered more and more as the explanation for more and more stuff that is going on. So, things may change and science may be able to fill in the black holes in some of the abounding theories it has created.

Could black holes be remnants of the vacuum?

But, for right now, it's more about what you want to believe in than it is about known fact.

Answer 4

Imagine standing in your back yard and throwing a rock up into the air. Gravity causes it to return to the ground. Even if you shoot a bullet up into the air it must return to earth because it does not have enough velocity to escape from the earth's gravitational attraction. Now imagine that you are within a black hole and point a flashlight up into space and the photons do not have enough velocity, even at the speed of light, to escape. This happens for two reasons, (1) the black hole is so massive (heavy) that its gravitational attraction collapses all atoms, molecules, electrons and neutrons, etc. into a single dot (like a period called a singularity) with infinite density and (2) you can get very close to the center of mass because it is a dot. The inverse square law shows that gravitational attraction weakens as you move away from the center of mass but increases without limit as you approach the center. Since the photons (and everything else) can not rocket into space from a black hole, there is no light to be seen at a distance; hence it "looks" black. Black holes can form when very large dense stars use up their fuel (hydrogen fused into helium, etc.) and lose enough heat at their centers to no longer resist the pressure from all the weight above. The collapse is sudden and creates unimaginable pressures as all matter falls to the center crushing everything.

Answer 5

They form from a mass that has a critical gravity, usually a star but sometimes a galactic centre, which is sufficient to collapse into a singularity. The gravity of a black hole is so great that not even light can escape, hence the term "black". Really they ought to be called "invisible".

Answer 6

Well black holes were orignally called drak stars then this american said black holes. Black becuase no light can escape its immense gravitational pull and hole becuase anything that comes beyond its event horizon is sucked in. A black hole is a star that is compressed into a small spherical ball. It has so much mass that the gravity is in-exscapeable. Not even light can escape it.

Answer 7

Stars are so dense, so they going to shrink by pull of gravity. but as the pressure going higher, star becomes warmer. and the atoms would begin to interact with each other and make a huge energy.actually the four hydrogen atoms join together and make a helium atom. so the heat of that would prevents from shrinkage. but as all the hydrogen turn into helium, star becomes cooler and it shrinks. if it is massive,(1.5 times bigger than our sun) it would shrink until all the particles in atoms touch each other. therefor it would create a huge gravitational force, which even attract the light! so it's black, because even light can get away from it.

Answer 8

black holes are stars, the difference is that nothing can escape its gravity. The way a star becomes a black hole is it implodes (the opposite of exploding), becoming a singularity.

The reason it's called a black hole is because we can't see it.

Answer 9

Black holes form when red giants collapse. They are "black" becuase they are invincible to the naked eye

Answer 10

black holes are when stars collapse. to be more specific i believe they are red giants. they are not really black. when we see them they appear to be black because there is nothing beyond. a black hole is a "hole" is space.