what is a black hole, in layman's language?

Answer 1

LAYMAN'S THEORY

Black holes are objects so massive and compact that no physical body or signal—not even light—can escape from their gravitational pull once it has crossed the so-called "event horizon" around the black hole (for a black hole of the mass of our sun the event horizon would have a radius of just 3 km, hence black holes are comparably small objects in astronomical terms). Besides the frequent stellar mass black holes (which are thought to be generated at the death of stars about 10 times or more massive than our sun) there is a second class of black holes, which reside in the centers of almost all galaxies and are a million to billion times as massive as our sun. Such so-called supermassive black holes are thought to be the central engine of "Quasars," the most distant and luminous objects known in the universe. Their electromagnetic emission is thought to arise when gas heats up to temperatures of million of degrees before falling beyond the event horizon of a supermassive black hole. In order to find evidence for the existence of such objects, one has to show that so much matter is concentrated in such a small volume that all alternatives to black hole can be excluded—e.g., dense clusters of dark astrophysical bodies such as planets, neutron stars, etc. This is a difficult task in extragalactic systems because of their incredibly large distance. The center of our home galaxy, the Milky Way, however, is about 100 times closer than our next major neighbour galaxy, the Andromeda galaxy. Therefore the undertaking of finding strong direct evidence for the existence of supermassive black holes is most easily done in the Milky Way. For probing the gravitational field at the center of the Milky Way one can use stars as test particles. Imagine the following scenario: If our sun did not give off any light, we would still know of its existence because the gravitational pull of the Sun (along with the angular momentum of the Earth) makes our home planet move around it once a year. In a similar way we have observed the movements of stars close to the supposed supermassive black hole, called Sagittarius A*, in the center of our Milky Way for over a decade. A star was found that moves around Sagittarius A* once every 15 years. By inferring the properties of its orbit with the help of Kepler's laws it was straightforward to show that the (dark) object that forces the star onto its orbit must have about 3.5 million times as much mass as our sun. Furthermore, this mass must be concentrated into a volume just about three times as large as our solar system. Since there is no other known physical object with these properties that can be stable over a significant length of time (compared to the lifetime of our galaxy of about 10 billion years) we concluded that the Sagittarius A* is indeed a supermassive black hole.

Answer 2

A black hole forms when a star collapses in on itself. The gravitational pull is so strong that not even light can escape it, hence the name "black hole." They say that if you look at the sky and see a spot that is ABSOLUTELY PITCH BLACK BLACKER THAN BLACK BLACK, that is a black hole. And no, the sky is not black at night, it is really dark blue.
There are two kinds of black holes. A rotating black hole or Kerr, Kerr-Newman Black Hole, which is the most common, and a non-rotating black hole or Schwarschild Black Hole.
Every black hole has an accretion disk, event horizon, and singularity. The accretion disk is like a cloud of stuff spiraling towards the black hole. The event horizon is the boundary where the escape velocity exceeds the speed of light (once something goes in it don't come out). Currently we don't know of anything that exceeds the speed of light. In the very center of a black hole is a singularity. Look it up because it is hard to explain.
A rotating black hole has two event horizons. As the black hole spins the outer horizon moves in and the inner moves out. Sooner or later the horizons will collide and cease to exist.
Since the black hole has no event horizon it is no longer considered a black hole. It is now a naked singularity. It is believed that the universe is formed from a naked singularity. The "Big Bang" is thought to have happened when the singularity exploded and all the matter packed inside started spreading out. The effects of the "Big Bang" are still occuring as our universe continues to expand.

Answer 3

An object whose gravitational pull inside a certain radius is so strong that nothing, not even light can escape it. A black hole forms when the amount of matter in the core of a star undergoing a supernova is great enough to cause a runaway gravitational collapse.

Answer 4

A black hole is a concentration of mass great enough that the force of gravity prevents anything from escaping from it except through quantum tunneling behavior. The gravitational field is so strong that the escape velocity near it exceeds the speed of light. This implies that nothing, not even light, can escape its gravity, hence the word "black.

Answer 5

Imagine that the fabric of space is a stretched sheet of rubber.
Now imagine the various stars as steel ball bearings of differing sizes laying on the sheet of rubber.Now they will create a depression in the stretched fabric in proportion to their mass.
The greater the mass,the deeper the depression.This indentation can be likened to the gravity of each star.
A black hole is so dense,that it makes an indentation so deep that anything which comes close is imediately sucked in to the hole.This includes any photons passing by as well.Thus creating a black hole.....
Get it?

Answer 6

A large star collapses on itself and gets more and more dense. It reaches such density that its mass is so great that light cannot even escape. The gravitational pull is so great that even light is pulled in. The rubber sheet with the steel balls in earlier answer is a very good analogy and adds deeper understanding of the actual situation which is more complicated.

Answer 7

A black hole is an immense amount of mass of which it's gravity is so strong that light cannot even escape.

Answer 8

take the hose of your vacum cleaner and stick it in front on your chest level have a friend stand varing distances away from you and release light weight objects. that gives you an idea of what a black hole does and is

Answer 9

A black hole in layman's terms: FAKE! There is no such thing as a blackhole, they are ridiculous creations to help explain why the galaxies and star systems aren't flying apart. Same thing with dark matter.

Do a search for "electric universe" because it's the future of astronomy and space research. Here are some pictures of some popular formations and phenomena in our solar system with the electric universe theory compared to leading theories:

http://i43.photobucket.com/albums/e397/Bigpappadiaz/040705olympus-mons.jpg

The Olympus Mons is a supposedly a massive shield volcano, the largest in the solar system. But look closely at the cauldera, and you'll see a most peculiar phenomenon: craters centered on other craters. A close up of the cauldera:

http://i43.photobucket.com/albums/e397/Bigpappadiaz/050606omcaldera.jpg

http://i43.photobucket.com/albums/e397/Bigpappadiaz/mars_topography.jpg

The topography of Mars. Notice how the northern hemisphere is whiped clean, and 3000 feet below the average elevation at the equator. Notice how the southern hemisphere is 3000 feet above the average elevation at the equator, and is crushed and blasted with craters all over the place.

Way back in the day a massive comet-like planet, spinning the opposite direction like Venus, passed by Mars and Mars discharged itself to the object. It lost TONS of electrons, its atmosphere, and 6000 feet of soil from its northern hemisphere. Before this object passed by Mars it passed by what is now the asteroid belt. It was much more powerful then, and the entire planet exploded. Then it passed by Earth, but it was not so bad by then.

This object probably was Venus. Earth is in a phase lock with Venus, that is every time we pass our closest to it it always shows us the same side. Venus used to be called the smoky planet, the hairy planet, the bearded planet. This thing had whispy filaments just glowing off it!

According to Greek mythology, Kronos (Saturn) swallowed all his children (the Gods, who were also associated with planets themselves) but his wife tricked him into eating a rock wrapped in fur and threw them all back up. Now what is this starting to sound like to you?

http://i43.photobucket.com/albums/e397/Bigpappadiaz/crater2.jpg

Another Martian crater, notice the splattering around it and the raised mound in the middle. In the very first picture I showed you there was an electric experiment. In the experiment an electric arc was striking a clay anode, and around the arc water was beginning to come up out of the clay and "sweat" away from the arc. Same thing here, only bigger.

http://i43.photobucket.com/albums/e397/Bigpappadiaz/051111lavachannels.gif

An area of Mars. Official explanation? Lava tubes. The REAL explanation? Massive tornadoes of plasma and lightning bolts.

http://i43.photobucket.com/albums/e397/Bigpappadiaz/sun2.jpg

Sunspots. These are some of the highest resolution pictures of sunspots, and what they appear to be are tornadoes.

http://i43.photobucket.com/albums/e397/Bigpappadiaz/041015solar-tornado.jpg

http://i43.photobucket.com/albums/e397/Bigpappadiaz/050617penumbra.jpg

So if these are tornadoes, they are running parallel to the surface of the Sun and are pouring into the sunspots. Sunspots show us that the area below the surface is cooler than the surface. The halo-like corona around the Sun is 300 times hotter than the surface. This is inconsistent with the theory that fusion takes place in the core, where it is the hottest.

What's actually going on is a massive electric current flowing through space passes over the Sun, heating it like the filament in a light bulb. This is why it rotates faster at the equator, faster on the surface, and why sunspots travel faster than the surrounding surface.

There's way more, but that's all I can type for now. Few more pictures:

Lightning on a golf course:
http://i43.photobucket.com/albums/e397/Bigpappadiaz/060309lightning.jpg

Lightning on Venus:
http://i43.photobucket.com/albums/e397/Bigpappadiaz/060309venus.jpg
http://i43.photobucket.com/albums/e397/Bigpappadiaz/060309venus-2.jpg

On the moon:
http://i43.photobucket.com/albums/e397/Bigpappadiaz/060308crater-2.jpg
http://i43.photobucket.com/albums/e397/Bigpappadiaz/060309hubble.jpg

Answer 10

a large star that has collapsed down to a very small size. all of the mass of the star is compressed into the small object. it has incredible gravitation. it's gravity sucks everything nearby(other stars, planets, even light) into it.