Monday, December 8, 2008

Is Anybody Out There?

Granted that there is lots of room for alternate universes right under your nose (if you're not with me on this, see my essay titled "Empty Space"), maybe--just maybe--there might be some way to communicate with them or at least to tell that they are here. Well, actually there might be a couple of ways.

Let's keep in mind that, if there are lots of other universes in and through and all around us as some theoretical physicists and cosmologists propose, there is no reason to assume that they are totally opaque to us. Just because all these universes can exist side by side, in and through and around one another without being grossly "aware" of one another, that is, without having much interaction because their physical laws don't permit the same energy levels, doesn't necessarily mean that they can have no--absolutely NO--interactions. In fact, why should they be cleanly separated? In a contrary sort of way, there is every reason to expect that they may have some interactions. Maybe the subatomic particles that seem to be constantly created out of nothing and to disappear into nowhere are really small enough so that they can slip and slide back and forth between overlapping universes.* Maybe that's where stuff goes when it disappears down a black hole--maybe it pops out of a "white hole" in another universe; or maybe it gets its energies so mashed up and confused that it creates an alternative universe.

First let's take a look (or "take a think") at the question of gravity leakage. There are four fundamental interactions or "forces" in our universe. By far the strongest has been cleverly dubbed the "strong force" (or "strong interaction"). The strong force acts by passing gluons between quarks and antiquarks to make protons and neutrons; in other words, it keeps the atomic nuclei of atoms from flying apart. It has a typical field strength 100 times stronger than the next strongest force, the "electromagnetic" force. We are all pretty familiar with the electromagnetic force; it's the one that lights our light bulbs, make magnets pull and push on one another, and all that. Actually the third force in order of strength, the weak nuclear force, has been shown to be the same as the electromagnetic force under extreme conditions (such as those that existed at the time of the Big Bang), so we can conveniently lump them together--as such, they're called the "electroweak" force.

The weakest of the fundamental forces is gravitation. It is by far--by FAR--the weakest. If the strong force were an elephant walking across a jungle meadow, then the electroweak force might be a wild hog or a deer. But gravity would be the tiniest little gnat, smaller than the smallest ant, walking across that meadow. To be sure, we need it just about the way it is. If gravity were much stronger or much weaker, the right kinds of stars wouldn't form to make the right kinds of elements, to make us. But it's still so out of line with the other fundamental forces that it makes one wonder.

At least it has made some theoretical physicists and cosmologists wonder, and one thing they have wondered is, maybe gravity is so weak because it--unlike the other fundamental forces--can trespass across to interact with other nearby universes. Maybe gravity seems weak to us because a lot of the force of gravity leaks out of our universe. If so, there should be some way to test for or measure the leakage. And some top scientists are thinking hard, trying to figure out how to do experiments to study this.

Here's another possible way we might detect other universes in and around ours. When super-powerful atomic-particle accelerators crash stuff together, a great flash of odds and ends of particles and forces is created explosively. I say "odds and ends," but actually the explosive mess consists of specific, known subatomic particles and forces. These can all be detected and measured near the crash site. And the pieces should all add up to the same total mass/energy before and after the crash (remember the law of conservation of matter/energy--it can never be created or destroyed--it is just passed around, like "e equals m c-squared" and all that*). The detections and calculations are formidable, but the Large Hadron Collider set to go on-line in the summer of 2009 (or back on-line after its opening mishap earlier in 2008), is capable of handling this problem and figuring out if there are certain "impossible" energy levels that are regularly leaking away into oblivion.

There are other ways, too: a curious void in the large dispersion of galaxies; delayed particles detected while the Large Hadron Collider is turned off (yes, OFF); etc.

So, stand by. News about other parallel universes may be just around the corner.

* Note that the tiny particles that are constantly being created and destroyed throughout the vast vacuum of space come into being in equal and opposite pairs--a particle and its anti-particle, and the tiny energy fluctuations are random, all within Heisenberg's uncertainty limits so there is no violation of the law of conservation of matter/energy.