This kind of stuff makes my head almost explode... I thought the universe was the whole thing.

u·ni·verse [yoo-nuh-vurs] –noun
1.     the totality of known or supposed objects and phenomena throughout space; the cosmos; macrocosm. (source: dictionary.com)

I agree,  once we find "another universe" they no longer are a universe each but one universe together.

Anyone seen the show "universe" on History channel?

I'm going to say it one more time - we don't know about the conditions 'before' the big bang. We don't know if all energy was accounted for 'prior' to the big bang (although again, if the big bang created both time and space, then is there such a thing as 'before the big bang'?). At this point in time, any speculation about 'before the big bang' is purely philosophical. We might expect that all matter/energy was accounted for, but it needn't be the case. If there was a beginning to time (maybe there was, maybe there wasn't), then energy could, philosophically speaking, have been created from nothing. This is because conservation laws are only applicable under the existence of time. But I can't stress enough that, even though some physical principles and observations may be referenced, everything about this stage of our universe is entirely and purely speculative and philosophical.

And we certainly don't know that big bangs happen on a universal time scale all the time. It's true that up until about a decade or two ago, physicists thought that a repeating cycle of Big Bang -> Big Crunch -> Big Bang -> Big Crunch ad infinitum was a likely scenario, but that theory was fallen almost completely out of favor in light of new cosmological observations.

To be more specific, time is relative to reference frame. The statement 'time is relative to light' actually opens up a can of worms. For one, if you could, theoretically speaking, hitch a ride on a beam of light, you would experience the entirety of time in a single, infinitesimal moment. The same is true of any other massless particl, like gluons, and also gravitons (if they exist - we've never observed or measured gravitons or gravitational waves, but we think they should exist). It's true that time is relative and passes at different rates in different places and velocities, but that relatively is not free-form. It follows a very strict set of rules, and we can still speak about things like 'the age of the universe' by determining standard measures of time. The trick here is that that standard measure would be different in different locations/speeds in the same way that time itself is, allowing for a perfect 'translation' if you will.

Edit: TheOneX explained it much more simply and better than i did, so... yeah.

The current concensus is that, if our observations are correct, then the universe is likely on a one-way ticket to 'death'. The manner of death, though, is debatable.

It might undergo what's called 'heat-death', where the universe ends up in a thermodynamic equilibrium of maximum entropy. Essentially, there is no free energy left available to.. do.. anything. Perfectly stable particles, if they exist, would be stretched evenly but infinitely thinly.

Another potential death scenario is called the Big Rip (which I think is kind of exciting ). Basically, the idea is that in a dark energy dominated universe (which we think ours currently is, and will continue to be - though it didn't used to be ), the observable universe actually shrinks with time. This is because the expansion of the universe isn't just matter and all moving away from each other, but spacetime itself actually 'stretches'. Once the observable universe becomes smaller than any particular structure (whether that's a galaxy cluster, a galaxy, a star, a planet, an atom, a nucleus, a nucleon, ...), then that structure will be ripped apart because there can be no interaction between its farthest parts. The observable universe at any given point would shrink to nothing, and the universe would essentially cease to exist.

It is all theory - more than that, most of what we've been talking about lately has been more philosophical theory, rather than scientific theory. But you are right - none of the possible scenarios that have been thought of include the matter and energy of the universe vanishing. But then again, how could they? The scenarios we've developed rely on the physical laws we know of - but the physical laws we know aren't capable of predicting a scenario in which that occurs. It would either violate energy conservation, or somehow predict the end of time and space itself (which our theories are inherently incapable of doing). So yes, as far as we know that won't happen, but we also don't know that it won't (or couldn't) occur (our understanding of the universe is incomplete). It's weird, and bizarre, and I'm not particularly comfortable with it either - but our comfort is irrelevant Hell, Einstein was as uncomfortable as you can get about quantum physics, and yet all the evidence points to the world not caring about his feelings.
 

But my point is that there may not be such a thing as 'before the big bang.' "Before the big bang could be many possibilities" is an understatement - a more correct statement would be, "Before the big bang could be anything, including nothing, not even time itself." Again, it's bizarre and strange and difficult to accept and, at least to me, impossible to really imagine or understand - but just like the universe doesn't care about our feelings, what came before, what might come after, or what might be outside the universe wouldn't care whether we can imagine it or not.

You're right that we can't logically travel at the speed of light, but light can. Light experiences all time (even if its infinite) in a single instant. Whether we can experience that a well is not really relevant. But more importantly, the speed of light isn't our standard time. Our standard time is not the speed of light (a speed can't be used as a 'standard time' - although a combination of speed and distance could be). We have a few standard times, actually. The two most prominent civilian ones now I think are Universal Time and International Atomic Time. Light is used as a means to measure the former, but it itself is not the standard. To go even farther, the SI Second (SI = Le Système International d'Unités) is defined by the atomic resonance frequency of caesium.

Ah, but logic is based on what we know. It's based on rules of what is and isn't possible. We know so little about the first moments of our universe (ie, after the big bang), and even less about what might have come 'before' it (if anything). This means that we can make all the logical arguments in the world, but that logic will be based on speculation. It's speculation based on what we are familiar with, but nonetheless it may very well not apply to the big bang. I agree with you - I can't comprehend the concept of 'nothingness' in this sense - I don't think anyone can. But again, an open mind means not writing off the unimaginable

You're wrong that Mayan and Egyptian techniques aren't worth much when talking about time. Yes, their methods weren't as precise as our methods today, but that is how science progresses - from less accurate to more accurate. I could define a standard measure of time to be the average period between two of my heartbeats at rest. If I measure time with it standing on Earth, then get on a spaceship and fly to Alpha Centauri at close to the speed of light and measure time using the same method, I will have a fairly accurate measure of time for both situations. And as long as I have all the data corresponding to my space flight, I would be able to accurately compare both time periods. Likewise, if I decide to use the rotation of Earth as a standard measure of time, I could do the same thing (assuming I have the tools on the spaceship to continue observing the Earth). The accuracy of your standard measure of time only depends on its consistency. The rotation of the Earth is slowing down, and so to maintain an accurate measure of time we have to compensate for it; and that is why the scientific definition of a second is defined using a much more consistent measure. To quote from wikipedia:

"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."

And, I also have to point out that the issues with measuring time are identical to the issues with measuring space. Time runs differently in different reference frames, but space compensates. If you know how to convert between the time in two different reference frames, you can figure out how to convert between spatial measurements without having to make any observations or anything, and vice versa. In relativity, there is something called the Invariant Interval. Time and space both contribute to it, and the Invariant Interval is constant in all reference frames. It is constant because even though time and space change with reference frame, they change in complimentary ways.

You are right, although I think accidentally! The definition I quoted above is actually incomplete. It is based on the resonance frequency of caesium on the Earth's geoid. This means that, if you are on a spaceship moving away from Earth very quickly, and you measure the resonance frequency of Caesium 133 to determine a second, you would have to make appropriate relativistic corrections (for both the velocity and gravitational dilation) in order to determine the actual SI second. So yes, the second is a value we choose for the speed we are moving through time, but it is 100% convertible to any other reference frame. My point here is that we did not invent time in any way, shape, or form. Just like deciding on a standard spatial distance like the meter does not mean we invented space, deciding on a standard temporal interval does not mean we invented time.

That's the problem with a lot of modern physics. It's extraordinarily difficult to understand, even conceptually. If you understand the mathematics behind it, it makes things it a lot easier to understand; but even for people with a background in math it can take quite a while - and lots of effort - to get through it all. For the average person, whose mathematical education largely ends after high school, that's pretty much out of the picture. Sadly, I think that's one reason why fewer and fewer people are getting into the mathematical sciences. 

With the discussion of Time in the last couple of posts, you may find the following an interesting read:

From an article found Here

Wow, thank you for the read! I've never heard of this theory before, it's definitely different.. and bizarre! But also very neat and rather elegant. I looked up the actual paper and it's an even better read than the article about it. Although it seems that the article about it is somewhat sensational - the paper doesn't go as far as to state or show that time is an illusion (the word illusion, or any similar word, is never used).

A good quote putting this in perspective is this: "it is wrong to say that time is an illusion. It is just reducible or non-fundamental, in the same way that consciousness emerges from brain activity but is not illusory."