Brainguy said:
Hi, I'm 11 so I probably will not understand your answer if you use a lot of math without explaining it. I heard that Heisinburg's unceartianity principle was what made people believe Yukawa(spelled right?) that there are such things as virtual mesons that can be pulled out of a vaccum, you CAN create something out of nothingness. I always thought the universae had definite boundries and E=mc2 ruled over the subatomic world. But how does Unceartianity prove this is correct? as far as I can tell, unceartianity just proves you can make a laser beam wider by making it shorter. is it that the photons that make up the wide-ness of the laser come from the vaccum? that's impossible because your laser beam will keep going till the battery dies.
~Brainguy
https://www.physicsforums.com/showpost.php?p=3240965&postcount=86"and check out Lisa Randall out on what goes on with those 'virtual' particles. She is one of the world's leading high energy physicists and wrote a popular book from which the quote is.
As an introduction and since you are just 11 years old I think that's an ideal place to start.
As you might have heard quantum mechanics is weird, their are those 'unspeakable' things happening between measurements. We can express them in mathematical formulas, but they do not make too much sense for our brains which are trained in a classical, non quantum physical world.
Quantum field theory, which is the theoretical framework where those 'virtual' particles arise, takes into account quantum mechanics and special realtivity, so that you have relativistic quantum physics, and thus describes Nature more acurate than quantum mechanics. The quantum weirdness is still all there, but in addition this theory is conceptual deeper and mathematically much more difficult to handle.
But let's take quantum mechanics. Say you measure the position of a single particle. Now even if you would know all about the forces acting on that particle, you only can give probabilities where that particle will be found some moments later. What that particle does between your two measurements is totally crazy and unspeakable, though we can write it down in mathematics which then give us the right probablity predictions for our measurements.
Now switch to relativistic quantum physics, where due to E=mc^2 we can convert energy into mass. That means that if we clash particles with very high energy, out of this collision might come different particles which are heavier or larger in number.
But much the same as in quantum mechanics (nonrelativistic quantum physics) you only can give probabilities of what you will measure (what particles will come out of the collision and in which angle). Also again, what goes on between measurements is complete quantum weirdness and unspeakable. In addition, as I said earlier, the mathematics that describe what goes one between the measurements and which give the probabilities prediction for the measurements are much harder.
Many physicists
interpret from one calculation scheme that works very well, that in those crazy and weird intermediate states between measurements there exist 'virtual' particles. Many others don't. But the majority, I believe, accepts it as an interpretational issue.Whether those 'virtual' particles, which are by definition not directly measureable, are part of a physical reality or mathematical constructs or just convenient visualizations is for you to decide after you learned some quantum field theory.
I do think they are part of physical reality.
But yes, truth is, that many physicists in the end do not bother too much about it and see it more as a philosophical question, fascinating as it is.
