Does the space also expand along with the expansion of the universe?

The same way as the expansion of the space-time was discovered. Select a few thousand of the billions of distant galaxies and measure the red shift, which is directly related to the velocity at which they are moving away from us.

But this isn't needed, there are already millions of measured red shifts on file. Some modern telescopes measure dozens or hundreds of galactic red shifts at the same time using fibre optics to separate images.

<QUOTE>which is the method of measuring the expansion of the space that is already infinite?</QUOTE>

You measure the distance to places at different distances and how fast they are moving apart. From that, you know the rate of expansion per unit of distance; that quantity is called Hubble parameter.

Note that the effect only becomes noticeable at sufficiently large distances, for which other forces don't have significant impact. Otherwise, it'll be like trying to see how old you are by looking yourself in the mirror yesterday and comparing with how you look today -- the aging effect is still there.

Space itself expands. It expands everywhere. Including inside objects. Including inside individual photons of light (that is the cause of cosmological redshift).

We do not try to measure the expansion over the entire universe... because we do not know how big the universe is.

The same way you do not measure the speed of a car by guessing how far it will travel over its entire lifetime... because you don't know what those numbers are. You measure the speed of a car by measuring how far it goes over a fixed period of time (60 mph really means "60 miles in one hour")

We measure the rate of expansion of space over fixed distances. If you take "one million parsecs" (roughly 3.26 million light-years), then the space over that distance will expand by 70 km in one second.

This sounds like a lot, but over that big a distance, the amount of "new space" over a second is a very small fraction.

Inside a human body, over a lifetime of 70 years, this is equivalent to the length of ONE ATOM over an entire lifelime. That is why you don't feel it. (Plus, over a lifetime, all the atoms in your body will have been replaced many times over).

Over the Observable Universe (the portion we can observe), the total amount of expansion over that distance of 13.8 billion light years (in look-back distance) is equal to the speed of light.

This does not mean that parts of the universe are "rushing away" at that speed. As far as each point is concerned, it could very well be stopped compared to its local space. It is the "amount of space" between us and "them" that is increasing at a rate equal to the speedof light.

If there are parts of the universe that are further out (and we are pretty sure there are*) then the distance between us and them keeps increasing so fast that even light from there will never get here.

What we perceive as the "edge" of the Observable Universe is not the limit of the whole universe.

Just like the horizon, as seen from a ship, is not the limit of the ocean. It is only the limit of what you can see of the ocean. If you have strong-enough binoculars, you would see that there are waves coming from further away, giving you the hint that the ocean continues beyond the horizon.

We have found the equivalent thing with the universe: it goes on beyond the limit of the Observable Universe.

It is space which is expanding (measured by observed red-shift). Space is not infinite. The universe may or may not be infinite, this is not known.

Imagine a sheet of graph paper, now imagine all the squares get bigger - so does the sheet!

There is nothing off the sheet, none of it exists, but the sheet is expanding.

We can tell its expanding because light that reaches us from a distance shifts its frequency. Almost like a train whistle that is high pitched approaching us, and gets lower once it passes and moves away. Light does the same thing, its shifts towards the red so they call it ;red shift'.

Space is expanding, but not the particles inside it.

The "expansion of the universe" IS the expansion of the space inside the universe. But not all the space; the expansion happens mostly in places where gravity is very weak. That is the space between superclusters of galaxies. Inside clusters, and inside galaxies, there is almost no expansion at all.

The measurement is done by considering the distances between superclusters.

No.

Space is what teh uinverse expands into