is space thining as the universe expands

[Dhaleth]

Just as matter and energy are different forms of the same thing, sort of like the heads and tails of a coin, I have read that space and time are the heads and tails of a different coin. I have further read that space is an actual fluid-like substance that is capable of being affected by the mass of the matter/energy complex by warping and what is called "frame dragging". Within the area affected by a gravitational field time, being the alter ego of space is affected by a slowing of its rate of passage relative to a place outside, or rather more distant from, the gravity field in question. So far, all this had brought me to remember that the universe is expanding. All the bodies and clusters of matter, as well as such alternate collections of energy, are moving apart. This is supposedly from the explosive energy of the "Big Bang" origin of the universe. Since everything is moving apart, the overall density of matter, and I suppose energy, is growing thinner and thinner I would expect that the same is happening to space. So this is my question[s]; is this happening to space? How could we know? What will happen when space has become so thin and tenuous that it begins to rip and tear? On the other hand if its density is somehow remaining constant, doesn't that sort of deny the statement of the 1st Law of Thermodynamics that nothing can be created or destroyed but can only change its form? If it turns out that the latter is true then would Fred Hoyle's idea of a flat, eternal universe where matter is being continually created, [I suppose out of the underlying quantum flux, if such a thing actually exists] be vindicated?

I've never read or heard of this idea before and am really curious about it all but, unfortunately, I don't have the scientific background to figure it out by myself, can you help?

[Rev. Green]

Yes, space gets less dense as the Universe expands. We don't yet know if this will continue for ever, or if it will eventually collapse.