according to quantum physic anything can happen in the universe so long as it is for a short enough time. for example a positron and a electron will spontaniously exist and then concel each other out. momentarily breaking the conservation of mass/energy law. but how long are we talking about in second for this to happen?
2006-10-12 22:21:51 · 3 answers · asked by supremecritic 4 in Science & Mathematics ➔ Physics
The example you give is not a violation of the mass/energy conservation law as the e- and e+ can be borne from gamma radiation.
However, in nuclear and quantum reactions, energy can be "borrowed" from nowhere to escape the potential well (known as "quantum tunneling". This is the breaking of mass/energy conservation of which you speak.
The answer to how long we are talking comes from the Heisenberg Uncertainty Principle:
∆E.∆t ≤ h-bar/2
∆E is the energy borrowed
∆t is the amount of time it can be borrowed for
h-bar is Planck's constant divided by 2pi
2006-10-13 01:22:31 · answer #1 · answered by Stuart T 3 · 0⤊ 0⤋
I'm no expert in this subject, but I've read a couple of similar articles, and I think it's something called the Planck time, which is the time it takes for a light particle to move one Planck unit of length (which is the smallest imginable length, I think. I know that's not very helpful in itself, but these units have known quantities. Hang on, I'll look it up.
Yes the planck time is approximately 5.4 x 10^(-44) seconds.
That means that in one second, there are 540 000 000 000 000 000 000 000 000 000 000 000 000 000 000 planck times.
2006-10-13 17:41:17 · answer #2 · answered by THJE 3 · 0⤊ 0⤋
When they cancel, somewhere in the universe a positron and and electron spontaneously appear at the exact same time, thus preserving the con of m/e law...
2006-10-13 05:36:00 · answer #3 · answered by thrag 4 · 0⤊ 1⤋