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Number distribution and mass distribution will be very different. For example, there are estimated to be trillions of objects in the Oort cloud, but their total mass is less than $0.1\%$ of the mass o …

Indeed, current observational data supports a model of accelerating expansion, in which the ultimate fate of the universe is a heat death or "Big Freeze". …

However, even in an infinite universe, the part of the universe that we can ever see or interact with is limited by the distance that light can have travelled since the Big Bang - we call this the observable … universe. …

Instead, the universe conforms to certain fundamental underlying principles such as conservation of mass/energy, momentum, angular momentum, and electric charge, which restrict how the properties of objects …

An "infinite" universe is shorthand for a universe in which all distances are finite, but there is no upper limit to the distance between two objects. … The size of the observable universe places an upper limit on the distances that we can observe, so we cannot tell whether the universe is infinite, or is just larger than the observable universe but still …

We know from observing the CMBR that matter and radiation in the universe soon after the Big were distributed almost uniformly. … The universe is therefore evolving from this initial near-uniform low entropy state towards a final high entropy state in which almost all matter and radiation has been absorbed by black holes. …

The hypothesis that the fundamental laws of physics are the same everywhere in the universe and at all times is based on empirical evidence. … Of course, our knowledge of the universe is limited to the observable universe and to the past (we have no knowledge of the future) so the most we can say is that this hypothesis has not yet been contradicted …

What we do understand is the state of the universe a very short time after the Big Bang and the laws that have governed the subsequent evolution of the universe. … As other answers have pointed out, this does not imply that the universe is deterministic. The answer to that depends on your chosen interpretation of quantum mechanics. …

What you are envisaging is called a unified field theory or Grand Unified Theory. It is an area of active research in particle physics. A Nobel prize almost certainly awaits anyone who can come up wit …

How can we tell whether the entropy of the universe $S(t)$ at some time $t$ is greater than or less than $S(t’)$ at some other time $t’$ ? …

We cannot know “for sure” that the universe beyond the observable universe is the same as the part of the universe that we can observe. … In this case, a cosmological model in which the universe expands uniformly in all directions and has no unique centre is better than one that assumes a centre of expansion that is so far away we can never …

To keep things simple, let's suppose your hypothetical universe just contains one quark. … As far as we know, quantum physics will still apply in your one-particle universe, and in particular the uncertainty principle will apply. …

Would any known laws of physics be broken if the universe cycled endlessly through a fixed series of states ? No, they would not - although it might be inconceivably unlikely. … Cosmologist Roger Penrose has proposed a cyclic model of the evolution of the universe known as conformal cyclic cosmology. …

An example of a decoupled species is the cosmic neutrino background which consists of neutrinos which decoupled from the rest of the universe when the universe was approximately one second old. …

If the universe is infinite, would it be homogenous ? As far as we can tell, the observable universe is homogenous at scales of 100Mpc or greater. However, this is an empirical observation. … There is no theoretical reason why the universe must be homogenous at large scales, and no theoretical reason why this homogeneity must extend beyond the observable universe. …