Does light dissipate in space?

Question

Does light dissipate in space by distance alone, without any other objects in between?

I'm wondering because there was a Start Trek:Voyager episode where they travel through a region of space that lacks stars, but would light from other stars even further in the distance still be visible or would they dissipate over a great enough distance?

Answer 1

No, light does not dissipate its energy as it travels through space. It can only dissipate its energy if it interacts with matter. Light is a form of energy, and does not need to be "replenished" once it is it emitted. This is because light is actually made up of an electric field and a magnetic field which produce and support each other as the light beam travels through space.

The only thing that stops this from going on forever is when a light wave interacts with some form of matter (ie. a planet, dust, gas etc...). Its energy is then absorbed by the matter. Sometimes the material may re-emit the light, but usually at a lower energy. Since space is mostly empty the chances of these waves encountering some matter is relatively small. Hence, light can propagate outward for long lengths of time.

Of course, as the waves spread out the intensity (or brightness) does gets weaker. This is because there are fixed number of waves spreading out into a larger area. This is known as "the inverse square law", because at any given point in space the intensity of the light decreases as the inverse square of the distance from the light emitting source. Nonetheless, its energy remains unchanged.

Answer 2

light would run as long as it does not bounce into something.

what i could imagine is, (according to Feynmans Quantumelectrodynamics) light does not run a straight path through space. however its unpredictable as long as it does not cause an effect anywhere. it does not run a straight path, it runs ANY possible path, and its a complex calculation what exactly happens.

Dim light from far away stars is dim, cause the probability of arriving is lower than if the star would be near.
also the ammount of light is different.

imagine your bathroom shower, and hold it away at further distances... seen it ? the same ammount of water spreads over a larger area, and you count less drops on the target.

this is how it works with light too

Along with that one need to imagine that space isn't really empty. In fact there is an Atom here and there. i guess it was something like 1 atom per cubic-kilometer (?) or so.
however there is a good chance of bouncing into such an atom, giving these hughe distances.

along with voyager, i would suggest having an area in space
where there is a dense cloud of cold gas around . blocking light from the outside. like a soap-bubble with black walls
from cosmological viewpoint i would find that odd, but anyway , i bet thats why its called science-FICTION.
if such a void would exists one must definedly measure the shells temperature, cause its inside the universe.
And nothing in space is much colder than a few Kelvin, like the background radiation.
this radiation aloe would keep temperatures of the voids walls up over longer time. so it must be detectable

Answer 3

light, in theory, can travel for an infinite distance in a vacum. there is no matter to deflect, refract or dissipate it. light is one of only a few things that can travel without a medium. so as the episode goes it is possible. realize that the light we see from other stars is "old light". it still has to travel the distance from the star, across space to earth. also notice that VOY is a part of hollywood and that there has to be light, real by science or not, otherwise it would be a black screen and how boring is that. but theoretically there would be light there.
side note, that was a good episode

Answer 4

Well, what you mean by "dissipate" might mean that as the light travels out in a sphere surrounding the point it originally came from, then it becomes weaker. as does any wave force that behaves like that including sound or gravity (if you consider that to be a force). Our sun is close by and so it looks and feels very intense, but the further you move away from it, the fainter it looks. As to the limits of any kind of visibility at all, then I must say "I really don't know".

Answer 5

if the body emmiting the light was big enough......
It might be easier to think of light as photons moving away from a source.
A beam of light diverges from it's source......
==========
1.
The moving of light quanta (photon) is not depend of a source.
So, thinking about photon you can forget about some " source" .
It means that photon is independent particle.
2.
Some say a photon "sometimes acts like a wave and
sometimes acts like a particle".
How can independent photon behave as a wave and also a particle?
3.
If quantum of light flies always rectilinearly c=1,
it is a mad particle. Is he really mad?
4.
And God said, Let there be light: and there was light.
And God saw the light, that it was good:
and God divided the light from the darkness.
5.
How could God do it , if the light quanta is independent particle?
===============

Answer 6

Light does not dissipate but we see it as being dimmer as we move away. The intensity goes down as 1 over the square root of the distance to the source. Think of it as the light going out like a sphere from the source and the farther you go away, the bigger the sphere so there's less light per unit area.

Answer 7

Light does not dissipate in space...light is continuous no matter what unless a solid non-translucent object comes in its way. For example we see stars that are millions of miles away...yet we still see them because nothing is blocking them and light is continous till blocked.

Answer 8

since the speed of light is a constand it is always 300000km/sec in a vacuum (space) therefore no, light will not dissipate, wen a star dies we can still see that light for often millions of years after its death depending on how far away from the star you are.

as an example if you are 20000 light years away from a star and that star dies we will still see its light for 20000years.

Answer 9

Time does not pass for photons traveling at the speed of light, so time as we experience it has no effect on light. It continues to travel through space until absorbed or reflected.

Answer 10

It might be easier to think of light as photons moving away from a source. When the photons start out from a point, they are close together and the source of them looks brighter. As you get farther away, fewer and fewer photons are hitting the place where your eyes can see them. The rest are dispersing in other directions and you can't see them. Thus the light from the source appears dimmer and dimmer.