reply to post by Maxatoria
would require us to have faster than light sensers so that we could measure the movement which to us non having access to marvin the martians
super gear is out of our league at the moment
In fact, we can measure the expansion of space quite easily.
Most people interested in this subject have heard of 'redshift', the downward shift in the frequency of any electromagnetic radiation being emitted by
an astronomical body moving away from us. There are two kinds of redshift, known as Doppler redshift and
. The former is caused by the relative motion of object
and observer through space and is the main component of the redshift we observe in relatively nearby bodies (those in our galaxy and neighbouring
The latter, however, is caused by very distant objects being carried away from the observer by the expansion of space itself. At such distances,
cosmological redshift completely overwhelms the Doppler component unless the source is moving at quite close to the speed of light.
By measuring the cosmological reshift at different distances we can work out not only the present but also the past expansion of space.
To answer the OP question, the expansion of space has no effect on the speed of light, only on its preceived frequency.
reply to post by CitizenNum287119327
If light can be a wave or a particle, then the wave could take 10 light years to get here for us to see, BUT, if it is a particle, could it be
instantly be seen? Meaning the particles could just bump a neighbour and so on...
The impulse would still travel from particle to particle at a finite speed, just as it travels through the steel balls in the executive toy you
mentioned. This speed would be much, much lower than the speed of light.
A photon is a light 'particle'. You see light when this particle strikes your retina and the impact causes a chemical change in your retina, which in
turn sends an electric current into your brain, which interprets the signal it receives as light. You don't see a photon; you see light.
To see a particle (or anything else) that is not a photon, you need to shine a light on it. A light is a stream of photons. Some of these bounce off
the particle and enter your eye, causing you to see it. You then see the particle or object, more or less brightly.
Another way to look at this is that light waves reflected off the object reach your retina and excite the electrons in the atoms of its cells through
a reverse photoelectric effect, causing some of them to come unbound from their parent atomic nuclei and travel along the conducting wire of your
optic nerve to your brain so that you see the object.
In other words, you can use either particle language or wave language to describe the phenomenon. Light waves and light particles are the same thing,
you see; it's not an either/or situation until the light interacts with some device designed to interpret it as one or the other.
All the time it's travelling through space between the object that emitted it and your eye, the light is both a particle and a wave. The wave is the
particle, the particle is the wave, and both travel at the same speed.
edit on 16/4/12 by Astyanax because: the two posts appeared in the wrong order.