speed of sound
Not much. The whole point of a black hole is that a lot of matter is concentrated in a fairly small space. The Schwarzschild radius of the Earth - i.e., the size into which it would have to be compressed to become a black hole - is less than 1 cm; the Sun would have to be compressed into a sphere with a radius of about 3 km. In general, the Schwarzschild radius is directly proportional to the mass. In a real black hole, the Schwarzschild radius corresponds to the event horizon - the point of no return.
Black holes are objects of such intense gravity that even light cannot escape, since the escape velocity at the event horizon is the speed of light. It would be better however to say that in order for the event horizon to exist, the object has to be dense enough that it's smaller than the Schwarzschild radius for that mass. This may seem counter-intuitive but it's possible for a great mass of lower density to allow light to escape for this reason - or, a much lighter object of higher density to not allow it to escape because the mass is inside this radius - hence it's possible to have a low-mass microscopic black hole.
Here is the problem:The speed of light is the absolute speed limit, according to current scientific knowledge. The area where light cannot escape is called the Schwarzchild radius. Once you're inside that radius, that's it for you. Sorry.Lightspeed is not necessarily the absolute speed-limit. There is a faster speed, but humans have failed to discover that speed just yet. In order to escape a black-hole you need to find a way to get through the outer wall before you cross the event horizon. The event horizon (EV) is the point in the black hole where all matter and light are crushed and absorbed into the void. So, as Argleargle said, if you are inside the Schwarzchild Radius, or in my case past the EV, you will cease to exist.DON'T SUPPOSE...Anyone's heard that Steven Hawkings has said that it is possible for certain particles to escape a black hole as "Haking radiation"? Of course, if you were Hawking radiation you'd probably still be dead, but it IS possible to escape a black hole.
If you mean to escape into space, that is called the "escape velocity". How much this is depends on whether you are talking about planet Earth, the Moon, the Sun, Jupiter, Sirius B, etc.
Before you can answer 'how big is a black hole?', you have to understand exactly what a black hole is. A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. That definition leads you to wonder slightly about gravity. If, for some reason, you throw a rock straight up into the air it will rise for a while, but eventually the acceleration due to the planet's gravity will make it start to fall down again. If the acceleration is enough, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity. The Earth's escape velocity is 11.2 kilometers per second and the Moon's is only 2.4 kilometers per second. After taking those two facts into consideration, look at a black hole. It is so massive that light does not travel fast enough to escape its gravity. Since nothing known travels faster than the speed of light, nothing can escape a black hole. Now, back to the original question 'how big is a black hole?'. There are many different ways to describe how big something is. Let's just look at much mass it has and how much space it takes up. There is no limit(in principle) to how much or how little mass a black hole can have. In theory, any amount of mass at all can be made to form a black hole if you compress it to the right density. Most of the black holes were produced by the deaths of massive stars, so scientists believe those black holes weigh about as much as a massive star. A typical mass for such a black hole would be about 10 times the mass of the Sun, or about 1031 kilograms. Astronomers also suspect that many galaxies harbor extremely massive black holes at their centers. These are thought to weigh about a million solar masses. the more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius(radius of the event horizon) and the mass are directly proportional to one another: if one black hole weighs ten times as much as another, its radius is ten times as large. A black hole with a mass equal to that of the Sun would have a radius of 3 kilometers. So a typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a galaxy would have a radius of 3 million kilometers. Whether you measure by mass or space taken up, black holes can be some of the largest objects in the universe.
A Schwarzschild black hole is a non-rotating black hole. The Kerr black hole is a rotating black hole. Since the latter is more complicated to describe, it was developed much later.A Schwarzschild black hole is a non-rotating black hole. The Kerr black hole is a rotating black hole. Since the latter is more complicated to describe, it was developed much later.A Schwarzschild black hole is a non-rotating black hole. The Kerr black hole is a rotating black hole. Since the latter is more complicated to describe, it was developed much later.A Schwarzschild black hole is a non-rotating black hole. The Kerr black hole is a rotating black hole. Since the latter is more complicated to describe, it was developed much later.
It depends on the value of the radius.
There are spectacular differences between black holes and Earth. Earth is a planet; a black hole is not. Usually black holes are remnants of stellar evolution, created at the end of a star's lifespan when its fuel is exhausted and collapses, producing a region of spacetime where escape velocity is greater than the speed of light; Earth by contrast is believed to have formed from a proto-nebula not (directly) from a star. The escape velocity of Earth is much less than the speed of light, and it lacks sufficient mass to become a black hole. A black hole has a singularity of infinite density; Earth has no such structure and could not approach infinite density. Earth reflects light, a black hole does not. The Earth's gravitaional radius is much smaller than its Schwarzschild radius; a black hole's is equal (or larger). Black holes evidence a type of matter known notionally as exotic which defies our current physical models; Earth's does not. Black holes bend space sufficiently to have a photon sphere; the Earth cannot have one.. etc. One coincidental similarity is that much of Earth's matter is a product of a supernova explosion (for example, elements with atomic numbers higher than that of iron); a black hole can also be created by matter associated with supernova explosion.
Assuming there is no air resistance, if an object starts at a speed of 11.2 km/sec, it can escape the gravitational field of Earth. This "escape velocity" is different for different planets, moons, etc.Assuming there is no air resistance, if an object starts at a speed of 11.2 km/sec, it can escape the gravitational field of Earth. This "escape velocity" is different for different planets, moons, etc.Assuming there is no air resistance, if an object starts at a speed of 11.2 km/sec, it can escape the gravitational field of Earth. This "escape velocity" is different for different planets, moons, etc.Assuming there is no air resistance, if an object starts at a speed of 11.2 km/sec, it can escape the gravitational field of Earth. This "escape velocity" is different for different planets, moons, etc.
Well isn't that just a fascinating thought! To turn Mount Everest into a black hole, it needs to shrink down to an unimaginably small size called the Schwarzschild radius. This radius is so tiny that if all of Mount Everest was somehow squashed into that space, it would indeed collapse to form a black hole.
One might be tempted to say a black hole is possessed of vast amounts of mass or gravity, but a better answer would be 'density'. A black hole comes into existence when its radius is smaller than its Schwarzschild radius; which allows for the theoretical existence of microscopic black holes of relatively low mass. All massive bodies have a Schwarzschild or gravitational radius; the earth's is about the size of a marble.. if all that mass could be crammed into such a tiny size, then it would become a black hole. The commonest type believed to exist currently is the so-called stellar mass black hole, which is consequential to the collapse of a massive star and a result of normal processes in stellar evolution, brought about by a mechanism related to the gravitational pull from the star's mass no longer being balanced by the outward degeneracy pressure once the star's fuel is exhausted.
The speed of the satellite will remain the same regardless of doubling the mass, as long as the radius of its orbit remains constant. The speed of the satellite in orbit is determined by the gravitational force between the satellite and the celestial body it is orbiting, not the mass of the satellite itself.