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Apna phone number register karein. Ab aap Whatsapp pe solutions paa saktey h, hum aapko message karenge. Did the Great Cosmic Designer initially intend the proton and neutron to have same mass but then threw in a bit more for the neutron as an afterthought? The neutron, as it happens, has a little more mass and thus energy than a proton and an electron combined. There is a general principle in nature that physical systems, when left alone, seek out their lowest energy state.
Sure enough, an isolated neutron will soon, within about 15 minutes on average, spontaneously turn into an electron and a proton, a process known as beta decay. Another particle, called an antineutrino, is also involved, but that need not concern us here because it is almost massless.
The only reason that any neutrons still exist is because, within a few minutes after the hot big bang that made the universe, some neutrons stuck themselves to protons. The strong neutron-proton binding force changes the energy balance — not by much, but enough to stabilise the neutrons. Had the Great Designer done it the other way round, with protons about 0. Under these circumstances, isolated protons would turn into neutrons rather than the other way around.
Some protons would be saved by attaching to neutrons. But hydrogen, the simplest chemical element, does not contain a stabilising neutron; hydrogen atoms consist of just a proton and an electron. In this backward universe, hydrogen could not exist. Nor could there be any stable long-lived stars, which use hydrogen as nuclear fuel. Heavier elements such as carbon and oxygen, made in large stars, might never form either. Without stable protons there could be no water and probably no biology.
The universe would be very different. The fact that the universe we know, including our own existence within it, hinges so delicately on the precise value of the neutron-to-proton mass ratio has led to heated debate among scientists.
But what are quarks? Quarks are fundamental particles, i. There are six types of quark, but I shall discuss only two of those types here. These two quarks are the 'up' quark u and the 'down' quark d. You will notice that a nucleon contains at least 1 up quark, and at least 1 down quark: the identity of the final quark, therefore, is what determines the identity of the nucleon itself. It follows, then, that a nucleon's charge is determined by the identity of its constituent quarks, and this is correct, because the up and down quarks have different charges themselves.
When you total the charges of the two different combinations, you will observe the following:. It is not well understood why an up quark has a different mass to a down quark, but this would be the only explanation for why a neutron is heavier than a proton.
The following article provides come contextual information on quarks, which the may be used to explain these mass differences in the future:. Why are neutrons heavier than protons?
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