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Black holes are invisible because their gravitational pull is so strong that not even light can escape once it crosses the event horizon. This means that they do not emit or reflect any light, making them impossible to see using traditional telescopes. However, scientists can detect them indirectly by observing the effects they have on nearby objects or through other forms of radiation emitted by material falling into the black hole.
There are several ways, which basically make that the black hole isn't quite invisible. Most of them (basically, points 2-5 below) rely on the black hole's gravitational attraction on other objects.
1) A black hole should emit Hawking radiation; but that's so weak that we may never be able to detect it.2) Gas clouds surrounding the black hole (outside the event horizon - the "point of no return") will get extremely hot, and emit radiation.
3) Matter falling into the black hole will emit radiation, due to the extreme acceleration. Once again, this is visible as long as it is still outside the event horizon.
4) Stars can orbit the black hole. From the orbits of the stars, the position and mass of the black hole can be calculated.
5) Light passing close to the black hole will change its direction. This can be detected. For more information, read about "gravitational lensing".
Please note that, while nothing escapes from INSIDE the event horizon, some black holes are actually among the brightest objects in the Universe. For more information, do some reading about quasars.
According to current theory, if a star runs out of fuel, and its remainder - usually, the part that remains after a supernova explosion - is greater than a certain critical mass (believed to be about one and a half, or perhaps two, solar masses), it will collapse into a black hole. Less massive stars become white dwarves or neutron stars, depending, again, on their mass.
They don't directly emit light, but anything falling into them will emit strong electromagnetic radiation - due to the acceleration of the matter falling into the black hole. Also, the black hole attracts all matter near it.
Black holes are thought to interact with the universe thermodynamically, such that they have a finite non-zero temperature and entropy. This is attributed to quantum effects near the event horizon which can produce a weak radiation (Hawking radiation). Models for its production include energy transfer to virtual particles boosted by the immense gravity of the black hole, producing particle pairs one of which could be radiated away from the hole; per Einstein's equivalence of matter and energy, a loss of energy would equate to a loss of mass. Over a long period of time, if the loss of mass is not balanced by new infalling matter, the black hole could potentially "evaporate" entirely. The rate of radiation is shown to increase as the size of the black hole decreases, so it's possible the black hole might disappear with a "bang." Some efforts are underway to detect these events.
Your question is almost a trick question because there is no way we can know what a black hole looks like. Per definition, nothing can escape a black hole, even light, so there is no light reflection from a black hole which will allow us to see it. This is why a black hole is often represented as a black circle because we do not see the reflected light (objects which do not reflect light appear black).
However, by observing stars orbiting the black hole we can calculate the mass required to make such stars have these orbits and that is how we deduct that black holes exists.
When a star 100+ times more massive than our sun dies out, it explodes into a very violent explosion called a supernova. Then after some time, gravitational collapse causes the debris of the star to form in a spiral-like shape, thereby forming a black hole.
There is no way (yet) to detect a black hole directly. Nothing escapes from a black hole, our scientific theories say, so the only way to detect it is indirectly, based on its gravity.
So when we see gas being excited to x-rays by the swirling turbulence of a strong but invisible gravity well, we can presume that a black hole is to blame. Or when a star appears to be moving in a binary system but there isn't anything else there, we can guess that perhaps a black hole is to blame.
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If your body is a black hole are you invisible?
No, a black hole absorbs all light that enters it, making it appear completely black. So if your body were a black hole, you wouldn't be invisible but people wouldn't be able to see you due to the lack of reflected light.
What is the first known black hole?
The first black hole discovered is Cygnus X-1, which was identified in 1964 as a strong X-ray source in the constellation Cygnus. It is a binary system with a massive, invisible companion that is believed to be a black hole about 15 times the mass of the Sun.
If nothing can escape a black hole in outer space how can you see photos of a black hole?
The "shadow" of a black hole that we see in photos is actually the boundary where light can no longer escape from the black hole's gravitational pull. It's not the black hole itself that we see, but the effects of its extreme gravity warping space-time around it. Telescopes like the Event Horizon Telescope capture these images using radio waves emitted by superheated matter falling into the black hole.
What kind of star is invisible?
An invisible star could refer to a theoretical black hole, which cannot be directly observed because light cannot escape from it. Alternatively, a brown dwarf, a failed star that emits very little light and is difficult to detect, could be described as invisible.
Can a black hole destroy matter?
Yes - The dense nature of a black hole rearranges and transforms matter into energy. In fact, even before matter crosses the threshold of the black hole's event horizon, the accretion disk of a black hole provides for a formidal barrier. Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe.
Are black holes invisable?
Yes and no. It is rather hard to explain, because black holes are so dark and black that no living creature can see them, which in a sense makes them invisible, but you can also see where a black hole is because it sucks in light, too, so that would also, in a sense make it visible, but the my main answer would be, no black holes are not invisible.
What is invisible because its gravity is so strong no form of radiation can escape from it?
A black hole is invisible because its gravity is so strong that not even light can escape from it. This phenomenon is known as the event horizon, which marks the point of no return for anything crossing it.
If your body is a black hole are you invisible?
No, a black hole absorbs all light that enters it, making it appear completely black. So if your body were a black hole, you wouldn't be invisible but people wouldn't be able to see you due to the lack of reflected light.
Are the things travel faster than light when they enter inside black hole so they become invisible?
No
Are blackholes really white?
No, black holes are actually invisible because it can suck it Light as well, so no light can escape from the black hole.
Can you make light circular?
Only around a black hole. There is a sphere around every black hole where light orbits the black hole.
How do you know when there is a black hole?
black holes are invisible because its gravitational pull is so strong even light cant escape from it. so what scientists do is they look at things around the black hole. if there is a black hold near a planet or star that objects orbit will be altered and it will be heating up from the friction of going into the hole.
Can you make a black hole inside a black hole?
We know nothing about the conditions within a black hole, but it seems unlikely that a black hole could exist within a black hole, or even if this concept would have any meaning at all.
What is invisible but can be seen by the naked eye and if you put it in a barrel it would make the barrel lighter?
a hole
Is a quasar a galaxy with a super-massive black hole in its center?
Yes, a quasar is a galaxy with a super-massive black hole in its center. The hole being invisible, all light vanishing from the great gravity. The quasar itself, among the brightest, most luminous objects in the universe, is being powered by an accretion disc around the black hole.
Is so massive that its gravity does not even let light escape?
The object you are describing is a black hole. It is a region in space where gravity is so strong that not even light can escape from it, hence why it appears completely black and invisible to outside observers.
What is the first known black hole?
The first black hole discovered is Cygnus X-1, which was identified in 1964 as a strong X-ray source in the constellation Cygnus. It is a binary system with a massive, invisible companion that is believed to be a black hole about 15 times the mass of the Sun.
