Quote:
Originally Posted by Venus007
Dear Hot Dr Sciences,
What exactly is the deal with quantum foam and do you think it is real?
Bonus question NASA scientists reciently discovered that lightening storms create small bits of antimatter, why doesn't this cause anhilation as I thought that if matter and antimatter got together it would be a cataclysm because of the enormous energy produced.
http://newsfeed.time.com/2011/01/12/...ng-antimatter/ |
I'll take these separately. I'll talk about quantum foam first because, ironically, it's actually the easier of the two subjects.
Prior to the first third of the 20th century, both space and time were thought to be separate entities and to be smooth, inert and constant. Starting with relativity theory and continuing with quantum theory, the picture changed dramatically. Firstly, Einstein demonstrated that space and time were neither smooth, inert or constant. Matter, for instance, curves space-time. In fact the best operational definition of gravity, so far, is the warping of space-time by the presence of matter. Quantum theory demonstrated that ALL our intuitions about the way the Universe 'really is' break down at the sub-atomic level. Cause and effect, for instance, are not quite so straightforward at the subatomic level. Particles--actually virtual particles--pop into existence and then just as quickly pop out of existence. These virtual particles are highly energetic.
The idea behind quantum foam is this. At the finest possible resolution (known as the Planck length which is ~1.612*10^-35) the structure of space-time is not smooth and continuous but is actually like foam with virtual particles popping into existence and then being annihilated. I wouldn't go so far as to say that quantum foam exists---in the sense that it has an independent existence but it is more of a concept to explain the energetic turbulance of space-time at the smallest scale.
There is one big problem, however. The issue is that mass (or energy) warps space-time (which, you'll recall, is what gravity is) and at present there is not a working theory of quantum gravity. All the other forces are carried by a particle (called a messenger particle) and there is a hypothesized particle called the graviton which would be the messenger particle for gravity. Except, we haven't observed it. The issue is that gravity is weak, REALLY weak. I know it doesn't seem like that every time you fall but consider this...when you walk, with each step, you are overcoming the force of gravity to lift your foot. Every time you pick something up, you are overcoming the force of gravity. You can even overcome the force of gravity to pick up a piece of paper using only a comb and static electricity. So the search for the graviton is the search for the most weakly interacting particle of them all! Until the graviton is found, there's no way to account for the warping of space-time that would be the 'froth', if you will, of the quantum foam.
As far as the anti-matter is concerned, it's not that ANY anti-matter would cause massive annihilation it's that sufficient quantities of it would. A small number of anti-protons encountering protons would annihilate one another and release a lot of gamma radiation. A large number of anti-protons would create a far larger release of energy with more destructive power. Fortunately, antimatter is very rare at this stage of the universe.
This was not always the case, in the very early Universe (before things had cooled down enough for atoms to form) there were almost, but not quite, equal amounts of matter and antimatter. LOTS of collisions took place in a massively energetic holocaust of explosions. The matter we see in the Universe now is the result of there being a slight bias in favor of matter so when all was said and done there was still some matter while all of the antimatter had been destroyed. This was actually good for the Universe because had this not happened the Universe would have had much more density than it does and so the formation of stars would have been much less likely.
Cheers
Aj