Why is a black holes not visible?

Question

pls i have to tell it to my teacher

Answer 1

A black hole, by definition, is a point in space where it is so dense that an near-infinite amount of matter is stuffed into a near infinitely zero space.  Thus, the gravitational energies are so powerful that not even light escapes it.  That's why they cannot be seen.

Answer 2

black holes are superdense object, with infinite mass. it keeps on sucking matter and sub-matter, and at the same time, they shrink to singularity (or infinity). these events make the black hole infinitely dense. as the density of the black hole increases, so does its gravity. this means that the black hole has infinite gravity.

when the black hole has infinite gravity, the acceleration due to gravity (denoted by the symbol 'g') becomes infinity (compared to 9.8 m/s^ -2) of earth's!). when 'g' becomes greater than the speed of light (= 3 X 10^8 m/s^ -2), light can no longer propagate in its normal way. once light hits the black hole, it cannot reflect back to our eyes, because light is held back by the gravity of the black hole.

no one actually knows the color of a 'black' hole!! we call it 'black' because light does not reach us from a black hole. Also, it is no hole!

the name 'black hole' is somewhat confusing.

you might be thinking, how can we 'see' black hole, if light does not reach us from a black hole. the answer to this is that we determine the presence of black hole as there is an area of 'light disturbance' around the black hole. also, if there are any stars nearby, a black hole will suck it off. as the result, the star will emit some X-Rays, which may reach the earth. if u have any further queries, please dont hesitate to mail me at [e-mail]

Answer 3

I think coz if a black hole was viseble to us we would have been long gone

a black hole sucks everything into him ...lol

Answer 4

  Simply because it emits no radiation.

  The surface escape velocity is greater than the speed of light.

Answer 5

black holes can be detected  whilst they are feeding. powerful jets coming from the poles when pointed towards us look like quasars. when they are not feeding then the only detectable  presence are

1 gravity observed by gravitational lensing this has been observed with telescopes

2 hawking radiation we haven't and instrument to measure this as  yet.

Answer 6

It is not visible simply because no light can escape it's powerful gravitational field.  Inside a certain radius from the black hole, which that radius is called the event horizon, light rays are bent back into the black hole, thus they cannot escape for anyone outside to "see".

Answer 7

To answer your question, let’s do an experiment in 3 different conditions:

1. You are standing on Earth, throwing a ball upward. Well, obviously, it returns back to you because of the same force that keeps our feet to the ground: Gravity!

2. Throw the ball, this time using a cannon, giving it higher initial velocity than your hand could. The ball leaves Earth and is lost in the darkness of space!

3. You are standing on, say Mars’ satellite Deimos, doing the same experiment. Due to Deimos’ weaker gravity compared to Earth, the ball leaving your hand could even leave Deimos, going out into space and never returning to you! No need to use cannons here. (So remember not to play soccer on Deimos. You could lose your ball forever!!)

So as you can see, two factors determine whether the ball returns to you or not: Gravity, and the velocity of the ball. The weaker the gravity and the higher the initial velocity of the ball, the higher is the probability for the ball to escape into outer space.

Back to your question … The gravity of a black hole is extremely strong. So you need to move as fast as you can to leave a black hole. But you can’t go faster than the speed of light. And the contest between gravity and light is ultimately won by gravity. That means even if you move at the speed of light (otherwise known as ‘the cosmic speed limit’), you can’t escape from a black hole’s gravity. And we see objects because light from them reaches our eyes (this light is either produced by the object, like the Sun, or is reflected light, like the moon). When even light cannot escape the gravitational grip of a black hole, it can’t reach your eyes, and therefore, you cannot see a black hole.

Hope this explained it.

Good Luck

Answer 8

No light comes off of it for you to see.

Answer 9

bcoz its gravity is so much that it even suck light so when no light no visibility................................. it.

Answer 10

A black hole is a star that spent it's nuclear fuel and can no longer counterbalance the force of gravity and collapsed in on itself due to it's own mass. In doing so, it became so dense it created a gravitational field so great that the escape velocity exceeds that of the speed of light.

As an analogy, the escape velocity of Earth is 11.186 km/s (40,270 km/h). Any object attempting to leave Earth traveling at a velocity less than that would be unable to escape and would return to Earth.

In the same respect, the gravity of a black hole is so great it prevents light from escaping, and so appears as an empty region in space, surrounded by an event horizon.

Answer 11

well it sucks in light. that is a known fact.

Because it sucks in light, light cannot bounce off of it and therefore cannot reach our eyes. So, we cant see it.

Some teacher....

Answer 12

for visibility of any thing light is necessary. Black hole gravity is unbelievable that even light cannot escape it and goes inside the black hole. so no light no visibility of black hole

Answer 13

Because their gravity is so strong it attracts everything, including EM radiation, photons traveling at 299,792,458 m/s.  

Answer 14

It is so powerful that Even Light cannot escape from it.  No question of seeing the black hole.