A Universe From Nothing

Last month's book for book club was called A Universe from Nothing by Lawrence Krauss. It was an interesting book, one of those astrophysics type where half of what you read you can't quite wrap your brain around, and the other half seems like it should be physically impossible, but apparently it's not.
Our book club was undecided about whether they loved it, but we are a pretty critical bunch, and I think over all it was a pretty good book. And ,since it was fairly short, I'd recommend it to those of you that are interested in the history of the search for dark matter and energy, and the origin of the (our) universe as well.
One of the biggest questions in cosmology is what produced the Big Bang? Most of us generally think in terms of cause and effect, and it only makes sense to us that if there was a Big Bang it had to come from somewhere, and be made out of something that was there before...only it's turning out that may not be true.
(See, this is what I mean about seeming physically impossible!) It certainly isn't true on a quantum scale where in the empty space between quarks (which make up protons and neutrons) particles pop into and out of "thin air" all the time! (The photo below was borrowed from a website called omnispace.org and if you click on the link below the image you can see a gif file animation that's pretty amazing!) That was one of the most interesting things I learned from this book. That empty space isn't really empty at all. WTF? Right?!

Click here to see animation!

So the idea is, if it can happen at a small scale, then why not on a scale the size of the universe? The only thing that seems to matter is that the total energy of the universe must always remain at zero, which apparently does.That might seem counter-intuitive too, but it's not once you begin to think about it. Stephen Hawking likened it (loosely) to making a hill out of dirt. In order to do that you must dig a hole of equal mass. So even though the hill might be high, it is balanced out by a hole equally deep. You are not bringing anything into the system or taking anything out of it either, you are just sort of shuffling it around. Yet still you appear to "make" a hill where there once was none. And so it might be with the universe. There was nothing needed, no outside cause to make the Big Bang, as long as the total energy remained at zero.
Now you might be thinking "Well, where does..."dirt" come from? Where does the system that totals zero energy come from?" And that's where it gets a little tricky. Because maybe the answer is that it comes from nowhere. Just like the particles and antiparticles that appear between quarks, so might our universe be. How could that happen you wonder? No one is exactly sure yet, but many think they are close. And it's all based on solid science, and observation (which the book goes into detail on, things like the Cosmic Background Radiation, and gravitational lensing etc...)
Part of it though, depends on which theory you buy. And each involves ever more complex physics . There is M-Theory and multiverses, string theory and so on, all of which can only truly be understood through some pretty hair-raising mathematics (and so becomes quite difficult for a lay-person such as myself to understand). It also depends on how you think the universe will end: with a"Big Crunch" or a "Big Freeze"? Will the universe collapse in on itself and form a giant black hole encompassing everything? Or will all the galaxies keep moving farther and farther apart until space cools, and all the starts die out? Does it even matter? Well, certainly not for us, or our grandchildren, or the rest of the human race, or any other living thing on our planet, or our sun, or our own home-sweet Milky Way galaxy. But for some distant future galaxy and  civilization it might. Krauss says in a mere trillion years (if the universe keeps expanding as it is now) those aliens will look up at the night sky and only see the stars from their own galaxy. If they develop the technology to gaze father out into the universe they will see....absolutely nothing.