Physics 101: Can Protons Or Neutrons Be Split?
Everyone has heard that electrons, protons, and neutrons are the ultimate constituents of matter, and that they cannot be divided further. Is that true? Not after the nineteen sixties!
Indivisibility: Right from the time philosophers started speculating about the constituents of matter they felt that the ultimate constituents should be indivisible. Greek and Indian philosophers were the first to propose indivisibility. By 1800 it became clear that elements were the most fundamental constituents of matter and John Dalton in 1800 proposed that each element is made up of indivisible atoms. While scientists kept working on the assumption that the atom was indivisible. J. J. Thomson and his team of British physicists in 1897 identified electron as a particle. Since the atom is electrically neutral, the discovery of electron immediately told them that the atom is divisible and is made up of negative and positive particles to make it neutral.
Eventually they discovered protons and neutrons also, and for several decades they felt that electrons, protons, and neutrons cannot be split up further. This is what is taught to children in schools today. However, this idea received a blow in the 1960s when some scientists proposed that only the existence of smaller particles inside protons and neutrons can explain their observed behavior.
Quarks: By 1968, experiments in particle accelerators at Stanford Linear Accelerator Center made it clear that protons did contain smaller particles inside it. Soon the same was confirmed about neutrons also. These particles were named quarks. (The picture on the right shows an early version of particle accelerators. It is in particle accelerators that they study protons and neutrons).
Finally the notion that protons and neutrons are solid bodies, and that they are indivisible, was "broken". Today we know that protons and neutrons are divisible. Originally they thought that there are going to be only 3 quarks but eventually they discovered 6 quarks that make up all the sub-atomic particles in the proton and the neutron family.
The biggest question today is whether electrons can also be split in the same manner. There are some suggestions that they can be, but the available evidence is in infancy at the time of this writing.
Can Electrons Be Split
This very interesting report from a team of scientist includes, “Electrons may be seen as small magnets that also carry a negative electrical charge. On a fundamental level, these two properties are indivisible. However, in certain materials where the electrons are constrained in a quasi one-dimensional world, they appear to split into a magnet and an electrical charge, which can move freely and independently of each other.”
According to some scientist, electrons are not made of up smaller things, so there is nothing to split. Other scientists believe that electrons are held together so tightly, that even the most powerful particle accelerators can’t get cannot get them to split.
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