|Would light ever stop traveling if there were no
objects to absorb the light.
|Question Date: 2011-10-13|
The simple answer to your question is that
light will keep going until it interacts with
something. It's really quite remarkable! Where
could we test this?
We see exactly this in
deep space! In fact, scientists have observed
light that has been travelling for over 13 billion
years. 13 000 000 000. To get an idea of how big
the number is, that's like comparing one second to
300 years. Or comparing the width of a human hair
(1 mm divided by 10), to the distance between here
and the Oregon border (620 miles). For more
examples, it's like comparing the size of an ant
(~5mm, or 1/5 of a inch) to the length of the
Earth's equator (40 075 km, or 24 900 miles), or 3
cm (~1 inch) to the distance to the moon! (384 000
km, 239 000 miles).
As you can see, light
travels for a very long time if nothing gets in
its way. We know from experiments that energy is
always conserved, so unless there's something to
which light can transfer its energy--and there's
not much in deep space--it will keep going!
Reference: NASA, science-nasa
No, in fact light only stops when it is
absorbed by an electron in an atom of an object.
Light in a perfect vacuum travels on at its full
speed until it hits something. That is why it is
so cool that when we see really ancient images of
far off "and very, very old" objects, that light
has traveled from that star through the universe
for sometimes billions of years and the first
object it hit was our telescope detector.
If there were no objects to absorb light, it
would keep traveling forever. Light is made up of
particles called photons that travel like waves.
Unless they interact with other particles
(objects), there is nothing to stop them. Unlike
some types of particles, they do not decay,
meaning that they do not spontaneously turn into
other types of particles. With nothing to stop
them and no chance of decaying, the will keep
going forever. However, scientists do not know
what shape the universe is or what would happen
when the photon reaches the"edge" of the universe,
if the universe even has an edge. Physicistsare
still doing research to be able to answer
questions like this. For instance, physicists want
to know whether or not the universe is infinite,
meaning that it goes on forever. If it is
infinite, the light would travel forever. If it is
compact (the mathematical term for "non-infinite
space"), then it is still possible for the photons
to travel forever because depending on the
topology (the mathematical term for "shape and
symmetry") of the universe, it may be possible for
the photons to wrap around to the "other side" of
the universe and keep going.
Ordinarily, no, light will continue on its path
forever unless it runs into something.
this said, very powerful photons (i.e. gamma rays)
can spontaneously transform into
particle-antiparticle pairs. I don't know if there
are any conditions necessary for this to happen,
Note from a scientist:
"There are requirements for this. The gamma ray
must be in the vicinity of a massive object, for
example a nucleus, for the particle - antiparticle
pairs to really exist. This is known as 'pair
production'. If this happens when there is no
external mass present, then the pair must have the
same momentum and therefore will mutually
annihilate instantly, creating a photon of the
same original energy and momentum.
This is a contributor to the vacuum energy, and
these 'virtual particles' are produced all the
time in a vacuum but have no real net effect in
normal physics, although it does lead to some
interesting implications such as the Casimir
effect and Hawking radiation."
We have no reason to believe that light would
ever stop traveling if there were no objects in
its path to scatter or absorb it. We detect light
from sources light years away with our telescopes
all of the time. Hope this helps
Nope! Light is a self-perpetuating
electromagnetic wave; the strength of the wave can
get weaker with the distance it travels, but as
long as nothing absorbs it, it will keep on
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