Light stop

sniper

Registered Member
hi

Would it be possible to slow light to a stop?

How could we do this and what would happen?
 
hi

Would it be possible to slow light to a stop?

How could we do this and what would happen?
It has been done and reported on

Briefly slowing light to a stop involved a very cold tube of something through which the light was directed

Mr Google and Miss Chrome will be a lot more helpful with a lot more detail

:)
 
It has been done and reported on

Briefly slowing light to a stop involved a very cold tube of something through which the light was directed
We have to be a bit careful in interpreting those experiments, which use ultra-cold gases of atoms. The speed that is being referred to is what's called the group velocity of the light, which is different from the phase velocity. I don't think those experiments bring a single wavelength of light to a stop.
 
We have to be a bit careful in interpreting those experiments, which use ultra-cold gases of atoms. The speed that is being referred to is what's called the group velocity of the light, which is different from the phase velocity. I don't think those experiments bring a single wavelength of light to a stop.

Link

https://www.nytimes.com/2001/01/18/...ull-stop-hold-it-then-send-it-on-its-way.html

I think this is a different article I read. Does not have the same look I recall the article I read

Articles I read some time ago may have been by Dr. Hau who went on to stop light soon after

Extract from this article

Two years ago, however, Nature published Dr. Hau's description of work in which she slowed light to about 38 miles an hour in a system involving beams of light shone through a chilled sodium gas.

You will need to read this to satisfy your query group velocity of the light, which is different from the phase velocity

More coffee needed

:)
 
who is Dr. Hau?

:D

A simple

Dr Hau stop light experiment

placed in Mr Google brings up the following

https://sciencenordic.com/computers...moves-it-around-and-makes-it-reappear/1408618

Extract

In 1999 the Danish physicist Lene Hau managed to slow down the fastest thing we know: light.

Since then she has continued her work with light at Harvard University.

In her latest experiment, she not only stopped the light but also moved it around, manipulating it for half a minute, before she made it reappear.

:) Mr Google greets me "What do they want now?" :) :)

:)
 
does a black hole stop light ?
Reminded me of a poem I wrote years ago, may even have posted it in the poem thread

Found a torch other day
Had a switch went two way
Push it forward out came light
Very shinny very bright
Slide it back out came blackness
Very dark very black
Found a torch other day

Anyway my understanding is Black Holes absorb light which fall into its gravity well and absorb the light's kinetic energy, hence no reflection

Guess destruction of light would be considered stopped. Scientists really want to stop light to study followed by starting it again

:)
 
would a non-reflective sheet of black paper stop light?
It would have to be truely non reflective in which case it would absorb the kinetic energy of light and heat up

It should not be said to reflect light as heat but to have absorbed lights kinetic energy and converted said energy into heat which it radiated out as of its own

Although that could be a difference without a distinction

:)
 
06:11 am 14 January
coffee finished breakfast finished
now thinking about the fence repair i need to do & wondering if i have forgotten something because it feels like i have.
Now 3am Darwin time
Thunder keeping me awake no rain
May as well do something :)
If get tired enough can sleep all day tomorrow, well as long as bladder holds out :)

:)
 
does a black hole stop light ?
No.

Interestingly, what a black hole does is that it bends space so much that once light crosses the event horizon it can only travel towards the centre of the hole; outward paths are no longer possible. The energy of the light ends up manifesting as an increase in mass of the hole. From another perspective (frame of reference), light falling into a black hole never actually crosses the event horizon, so all "information" in the light remains at the surface of the hole, in some sense. We don't see light from the horizon (hence black hole) because light propagating outwards from there is red-shifted so such a degree that it would have no energy by the time it reached us (outside the hole).
Light only has kinetic energy
I personally wouldn't describe it as kinetic energy, though that's not unreasonable. The energy of light obeys somewhat different rules to the kinetic energy of massive particles.
would a non-reflective sheet of black paper stop light?
Yes, it absorbs the light and heats up a little in the process.

There are some interesting youtube videos about the blackest available paints, which are very very black indeed. They absorb well over 99% of the incoming light.
 
Yes, it absorbs the light and heats up a little in the process.

There are some interesting youtube videos about the blackest available paints, which are very very black indeed. They absorb well over 99% of the incoming light.
nasa
Singularity Black sucks up 98.5 percent of the light that enters it.
 
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