- #1
Mabcs
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Why are black holes black even though light(photons) has no mass? Gravity shouldn't affect it.
Why do black holes have such strong gravitational pull?
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In summary, a black hole is a region in space with an incredibly strong gravitational pull that even light cannot escape from. They appear black because of this intense gravity, and nothing can escape once it crosses the event horizon. While they do last a very long time, they will eventually evaporate through Hawking radiation. Black holes are not dangerous for us unless they are very close, and they actually play a crucial role in the formation and stability of galaxies.
- #2
ImaLooser
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Mabcs said:
Gravity does affect light. I think even Isaac Newton suspected that. Albert Einstein calculated the effect of gravity on light, and he was right. As far as we can tell, black holes behave quite as he predicted, even though he neither knew nor believed they existed and didn't like the idea.
The modern view is that mass bends space. Everything is effected by that, mass or no mass. In fact, all masses move through space the same way. It doesn't matter how heavy or dense they are, what shape, etc. Space bends the same for everything, light included.
It takes a little getting used to, but it makes sense.
- #3
Yosty22
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Thinking about a typical representation of gravity in the classroom, just picture a trampoline with a bowling ball on it. The mass warps the fabric of space time. As stated above by ImaLooser, Einstein calculated the effect of gravity on light. Since light is affected by gravity, it is then easy to see how black holes are black. Once you can understand that light, although massless, is affected by gravity, the rest of your question falls into place.
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tiny-tim
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Welcome to PF!
Hi Mabcs! Welcome to PF!
energy is mass, mass is energy
light has energy, so light has mass
(it doesn't have rest-mass)
Hi Mabcs! Welcome to PF!
Mabcs said:
energy is mass, mass is energy
light has energy, so light has mass
(it doesn't have rest-mass
)- #5
pmacias
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Black holes are black because they have such strong gravitational pull that nothing, including light, can escape from them. This is due to the immense amount of mass concentrated in a small area, creating a gravitational force that is strong enough to trap even the fastest-moving particles, such as photons. The concept of gravity affecting light may seem counterintuitive, but in the theory of general relativity, gravity is seen as the curvature of space-time caused by massive objects. This means that even massless particles like photons can still be affected by gravity. Additionally, as an object gets closer to the event horizon of a black hole, the gravitational pull becomes stronger and time slows down, making it appear as though the object is frozen in place. This is known as gravitational time dilation and further contributes to the black hole's ability to trap light. In summary, black holes are black because their immense gravitational pull traps all forms of matter and energy, including light.
FAQ: Why do black holes have such strong gravitational pull?
What is a black hole?
A black hole is a region in space with such a strong gravitational pull that nothing, including light, can escape from it. It is formed when a massive star dies and its core collapses under its own gravity.
Why are black holes black?
Black holes are black because of their intense gravitational pull. The gravity is so strong that it even pulls in light, making the black hole appear dark to an outside observer.
Can anything escape from a black hole?
No, once an object crosses the event horizon of a black hole (the point of no return), it is impossible for it to escape. This includes light, which is why black holes are black.
Do black holes last forever?
Black holes do not last forever. They slowly evaporate over time through a process called Hawking radiation. However, this process is very slow and for all practical purposes, black holes can be considered permanent objects in our universe.
Are black holes dangerous for us?
No, black holes that are far away from us do not pose any danger. In fact, they are essential for the formation and stability of galaxies. However, a black hole that is close enough to our solar system could potentially be dangerous, but the chances of that happening are very slim.