Does it stop somewhere or does it keep getting smaller and smaller ? What limits have we reached ?
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It's believed that subatomic particles like electrons and quarks are elementary particles, meaning they don't get any smaller. But who knows 50 years ago we thought that baryons like protons were elementary particles, but they turned out to be made of quarks, so I wouldn't be surprised if they did get smaller. Scientists are now trying to say that all of these particles are made up of "strings", this is called String Theory.
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Theoretical Physics is looking for a Theory of Everything. One promising possibility is: String Theory or M-Theory. If correct all matter and energy is made up of tiny vibrating strands or loops of pure energy. How these strings vibrate determines particle they make. Do they exist?
Depends on which physicists you talk to. You get 2 answers.
"It is too elegant not to be true."
"If you cannot prove it, then no one should believe it."
The split is roughly 50 - 50.
Strings are attractive because of the depth and richness of the supporting math and that math is internally consistent. You can start from different spots and work to the same answer (Sort of like solving a motion problem in Newtonian Physics by using Energy, Momentum-Impulse, or Newton's Equations of Motion. It does not matter which you use, you get the same answer.)
A complaint against Strings is it produces strange results, which we do not understand. This may or may not be a fatal flaw. It is sort of like the equations of Electrodynamics involve square root of -1 which we know does not exist. So, is there a fatal flaw in Electrodynamics or do we just shrug our shoulders and solve for square root of -1. Electrodynamics got out of this problem by introducing a second dimension. Strings also has a CYA. Two actually. 1) Like the rest of Quantum Mechanics maybe some of the strange results apply only at the quantum level. 2) Strings is a multi-universe theory ==> Strings are more robust than we thought and the same equations apply to all universes. ===> The strange results apply not to this universe (and can be disregarded) but to others. Our problem is to figure out which results apply to our universe
http://en.wikipedia.org/wiki/M-theory
Depends on which physicists you talk to. You get 2 answers.
"It is too elegant not to be true."
"If you cannot prove it, then no one should believe it."
The split is roughly 50 - 50.
Strings are attractive because of the depth and richness of the supporting math and that math is internally consistent. You can start from different spots and work to the same answer (Sort of like solving a motion problem in Newtonian Physics by using Energy, Momentum-Impulse, or Newton's Equations of Motion. It does not matter which you use, you get the same answer.)
A complaint against Strings is it produces strange results, which we do not understand. This may or may not be a fatal flaw. It is sort of like the equations of Electrodynamics involve square root of -1 which we know does not exist. So, is there a fatal flaw in Electrodynamics or do we just shrug our shoulders and solve for square root of -1. Electrodynamics got out of this problem by introducing a second dimension. Strings also has a CYA. Two actually. 1) Like the rest of Quantum Mechanics maybe some of the strange results apply only at the quantum level. 2) Strings is a multi-universe theory ==> Strings are more robust than we thought and the same equations apply to all universes. ===> The strange results apply not to this universe (and can be disregarded) but to others. Our problem is to figure out which results apply to our universe
http://en.wikipedia.org/wiki/M-theory
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There are two types of particles.They are elementary particles and composite particles.Elementary particles have no smaller units but composite particles are made up of quarks & these quarks are bounded by gluons.Smaller units than quarks have not been found yet.