5 Forces That Keep the Universe Together
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The weak force is what is responsible for light and heat coming from the
sun, as already noted. At the core of the sun, there are ionized hydrogen atoms
(protons), constantly hitting against each other to fuse into helium atoms,
due the dense, hot environment. The temperature of the core of the Sun is
nearly 15 million degrees Celsius. In the fusion process, protons and electrons
release neutrinos together with the fusion energy, which is emitted as light and
heat from the center of the sun. The heat released in the process puts outward
pressure on the matter at the core, which is trying to contract inward because
of gravitational force. This is much like boiling water in a covered pan that
pushes the lid up, despite gravity’s pull keeping it in place. It is therefore a
constant tug of war between the gravitational force pulling matter at the solar
core towards the center, and the force of nuclear reaction generated heat that is
trying to push it outward. We will get into more details of this as the neutrino
story evolves.