Black Holes?

Question

k, now i've been reading these astrology magazines and i just hit the topic of black holes. I'm sure everyone knows how black holes have such a great gravitational pull that they pulll everything into them including light. which is said to mean that they're pulling things in at a speed greater than 186,000 ft/s... soo my question is, how can you see a black hole at all if the said is true. Dont you need to have light to see? If all the light needed to see the black hole is being sucked in, destroyed, or w/e it is a black hole does shouldnt it be sort've invisible?
Theres probabaly a simple answer to this but i just cant think of it.

Answer 1

I'm not a physicist but I do know that gravity bends light and with a large enough gravitational field in a small enough area, light coming from behind a black hole would probably be bent completely around it so that the black hole would not be apparent even as a black spot in space, thus making it appear to be invisible.

Answer 2

Good question. You CAN'T see a black hole directly, but you can see the way it affects the things around it.

For example, it's known that anything with a mass-to-radius ratio greater than about 6 * 10^26 kg/m must be a black hole (because that's the critical ratio at which the escape velocity exceeds the speed of light). Also, by watching stars etc. orbit around other things, you can get an idea of the mass and radius of the "other things". So sometimes you can prove that the mass & radius are such that the "other thing" must be a black hole.

Likewise: as matter gets very close to (but not "inside") a black hole, it accelerates and creates a huge amount of friction with all the other matter that's crowded around it. This friction creates x-rays and other radiation with a particular signature which matches what you'd expect from a black hole (but not what you'd expect from anything else). So that is good evidence that a black hole is in the middle of all that.

Answer 3

Black holes are hypothetical chemical mass structures with properties that defy imagination.
They have been postulated a long time by scientist as being an invisble structure which could be of a size in the nanometer range (that is even smaller than a Neutron) having an almost infinite density of many many folds of that of the Neutron.
The Neutron after its discovery in 1932 was believed to have been the most dense compound mass structure of the Universe.
Note The bigger the mass of a black hole the less dense it is. The smaller the mass of a black hole the denser it is.
Now science indicates that there exist in the Universe a multitude of black holes that suck in everything in range.And nothing can escape beyond their Horizon.
Its a scary structure. Should there ever be a space travel to mars and the space module was to encounter a black hole it would disapear just like the Ships in the Bermuda triangle.

Now this is what the Science theory of singularity alludes
to ,concerning Black Hole.
Since we cannot see them with a telescope we have to assume that Cosmologist are right about Black holes.
Then this is what we have to believe . If they say Black Holes exist then, we have no choice to believe that they exist.

Answer 4

An object with such powerful gravity that nothing can escape from it, including light. The black hole's mass is concentrated in a point of almost infinite density called a singularity. At the singularity itself, gravity is almost infinitely strong, so it crushes normal space-time out of existence. As the distance from the singularity increases, its gravitational influence lessens. At a certain distance, which depends on the singularity's mass, the speed needed to escape from the black hole equals the speed of light. This distance marks the black hole's "horizon," which is like its surface. Anything that passes through the horizon is trapped inside the black hole. Black holes come in several varieties, depending on mass.

Answer 5

this is absolutely true. a black hole itself cannot be seen. but the matter surrounding the black hole can definitely be seen. as the matter circling the black hole approaches the event horizon (the point past which light cannot escape), it rubs agsint other matter at such great speeds that they produce heats and X-rays. these powerful X-rays are how we detect black holes. even if they didn't give off X-rays, wouldn't it be a little odd to see a place in space where you can't see anything, but other objects are attracted to it?

also, the speed of light is not 186,000 ft/second.... its 186,000 MILES per second.

Answer 6

"I read the news today oh, boy
Four thousand holes in blackburn, lancashire
And though the holes were rather small
They had to count them all
Now they know how many holes it takes to fill the albert hall..."

If CERN gets its way, we might just experience first hand knowledge of blackholes.

btw, unless you get your DSL in a cave, you recognised that as "A Day In the Life" ; a Beatles song.

When anything heads away from a gravitational object it is slowed by it. Except light, light speeds away from even heavy sources of gravity always at the speed of light. So, how do Black Holes 'capture' light? Well, they DO, sorta... you see, as light speeds away from a deep gravity well, it doesn't lose speed, but it does get redshifted. A black hole redshifts light back to nothing.

Black Holes should have been the National Symbol of the USSR... because the can shift anything red.

(that was a joke.)

Answer 7

Um...not to get anal, but you have probably been reading 'astronomy' mags, not 'astrology' mags.

As for the detection of black holes, we look for odd behavior in celistial bodies that are close to them. Remember, much of what we know about the universe comes from guesswork and theory, not direct observation. For instance, if a scientist detects inconsistenties in a planets orbit, he can figure what the orbit SHOULD be, then determine information about what might be affecting the orbit, i.e. a 'hidden' or undiscovered moon, etc...

Black holes ARE invisible to the naked eye, but the laws of physics make them apparant to theorists. When you eliminate all the other explinations for behavior of the celestial bodies near them, thier existance becomes the only logical explination remaining.

Answer 8

A black hole is not invisible per se. If a black hole where close enough for viewing, you would see a black non-reflective disk. Because a black hole has mass, you would not see through the thing (true invisibility). You would just see a dark circular spot with blazing hot plasma swirling about it.

Answer 9

You see it indirectly, by the gravitational effects it has on other astronomical objects. Or if it is too close to a star and it is "cannibalizing" it. Check out pictures of Sagittarius A, the black hole at the center of the Milky Way at chandra.harvard.edu

Answer 10

I didn't know the astrologers had started talking about black holes.

Anyway, the hole itself is invisible, but gas that falls into the hole gets very very hot (billions of degrees) and glows very brightly. That bright emission shows up in x-rays and sometimes visible light.