So that's why black holes can absorb light eventhough it doesn't have mass because it can bend spacetime, but that's just my oppinion
what do you think?
what do you think?
Hi,So that's why black holes can absorb light eventhough it doesn't have mass because it can bend spacetime, but that's just my oppinion
what do you think?
Playing devil's advocate here. So what happens to a photon hitting a block of light-absorbing material, say carbon? Does it travel indefinitely within the block?Interesting though, the photon is not at rest.
Hi,Playing devil's advocate here. So what happens to a photon hitting a block of light-absorbing material, say carbon? Does it travel indefinitely within the block?
Hi,I asked because of the statement "the photon is not at rest". Just wondering what happened if a photon was 'brought to rest' by hitting something solid. I agree with the conversion to heat energy, but is there an instant when the photon still exists but is momentarily at rest?
http://www.askamathematician.com/2013/07/q-what-does-it-mean-for-light-to-be-stopped-or-stored/I asked because of the statement "the photon is not at rest". Just wondering what happened if a photon was 'brought to rest' by hitting something solid. I agree with the conversion to heat energy, but is there an instant when the photon still exists but is momentarily at rest?
So, light isn’t being “stopped” it’s “imprinting” on some of the electrons in the crystal that are in very, very carefully prepared states. This imprint isn’t light (so it doesn’t have to move), it’s just excited electrons. That imprint lasts for as much as a minute; slowly accruing errors and fading. After some amount of time that imprint is turned back into light, and it exits the crystal at exactly the speed you’d expect. What makes the experiment most exciting is that this experiment has proven to be an extremely long term method for storing quantum information, which has traditionally been a major hurdle. Normally a quantum computer (such as they are) has to get all of its work done in a fraction of a second.
The photons would most likely be converted to electrons via the photoelectric effect. And depending on the isotrope of carbon in question those electrons would either generate electricity or heat. Or maybe you were thinking something else?Playing devil's advocate here. So what happens to a photon hitting a block of light-absorbing material, say carbon? Does it travel indefinitely within the block?
Basically what I was saying WRT the PE effect. Light doesn't carry momentum in the classical sense ofI think it first generates a current and that current then generates heat. The current may not be the same as we normally think of current (as more or less following a single path) but since the electrons move we might still think of it as a current.
Ha! So, what happens to the photon that gets "trapped"????...that a black hole can trap.
No one has yet given a good answer(s).Here are two more games for you:
1. You're an astronaut who just fell past the event horizon of a black hole. Look up: what do you see?
2. Forget about speghettification. How long till your atoms hit the singularity?
When heat is generated that excites the electrons so the electrons move faster. That could be interpreted as an increase in current, although the current direction in this case could be random not the usual current like how we usually think of current flow.Basically what I was saying WRT the PE effect. Light doesn't carry momentum in the classical sense of
the word. When it impinges on a substance different things can happen. Sometimes only electricity flows but at other times
heat can be generated. There is even the possibility of a nearly complete conversion to heat which should result in an equal but opposite force appearing on the surface of the substance in question.
The truth is we really don't know for sure.Ha! So, what happens to the photon that gets "trapped"????
From an observer outside the event horizon, it asymptotically approaches the event horizon but never penetrates. It's wavelength drops (again asymptotically and with respect to the outside observer) to zero. Poof! Is it gone?
But what does the photon see? Or, more realistically, what does an observer see who is contained within the event horizon?
I asked two questions weeks ago:
No one has yet given a good answer(s).
True but of course current has no real meaning unless you are talking about flowing from one definite point to another (and heat is mostly vibrational anyway).When heat is generated that excites the electrons so the electrons move faster. That could be interpreted as an increase in current, although the current direction in this case could be random not the usual current like how we usually think of current flow.
A black hole often evokes the image of a mathematical profundity, a singularity within the fabric of spacetime that sucks all things nearby to the doom of the fifth dimension. In reality it is just a star. And it's effect on the curvature of spacetime just results in a mass that occupies a much smaller space than usual. Light incident to the normal of it's spinning surface gets sucked up while the axes spew out light and other forms of energetic material.Ha! So, what happens to the photon that gets "trapped"????
From an observer outside the event horizon, it asymptotically approaches the event horizon but never penetrates. It's wavelength drops (again asymptotically and with respect to the outside observer) to zero. Poof! Is it gone?
But what does the photon see? Or, more realistically, what does an observer see who is contained within the event horizon?
I asked two questions weeks ago:
No one has yet given a good answer(s).
Wrong! If space were not a medium then accelerated reference frames would be no different from inertial ones. But the aether reacts to changes in motion and thus accelerations lead to gravitational (and even electromagnetic) effects.In response to the OP, I wouldn't call spacetime a medium -- spacetime is not a physical thing, rather it's a mathematical framework, like a coordinate system. We can't measure spacetime, but we can measure the distances between physical things, which gives us a metric, which we use to model the geometry of our universe.
If it helps to think of space as some kind of medium, we may say that space is made of quantum fields, and the medium of electromagnetic waves is the electromagnetic field. Likewise, the medium of gravity is the gravity field, and since it's a universal field, it imposes a geometry. Spacetime is just a handy coordinate system for this geometry.
Careful here. I've noticed much discussion above about "distance" and "time" in the context of relativistic phenomena. In these realms, there is much argument to be had between individual observers! To claim "smaller" or "bigger" or "faster" or "slower" is only valid with respect to a single observer (or to multiple observers present within the same frame of reference). The significance of this point cannot be understated or ignored.And it's effect on the curvature of spacetime just results in a mass that occupies a much smaller space than usual.
For the sake of simplicity, can we limit the discussion to non-rotating black holes? While I assume that non-rotating black holes are unlikely to exist, the math just gets unreasonably complicated what with space-time getting all swept up in the rotation and making life difficult for us laymen. For my thought experiments, I'd also like to assume that photons, observers, etc., are travelling perpendicular to the event horizon. This should be good enough for government work.Light incident to the normal of it's spinning surface gets sucked up while the axes spew out light and other forms of energetic material.
I am trying to avoid discussion of the physical effects of proximity to a singularity (whether inside or outside of the event horizon). I am well aware that biological entities would encounter difficulty near the event horizon of all but the largest black holes. My questions were more of the line: How does your perception of space/time change as you journey from beyond the event horizon to your final destination at the singularity?An observer standing at the event horizon would first notice younger feet...followed by a strange burning sensation as they finally reached the surface! (A big enough black hole might forestall the moment indefinitely of course.) I wonder would it feel cool all the way down?
by Jake Hertz
by Jake Hertz
by Jake Hertz