The sun can't shine without quantum physics.

The Sun can't shine without Quantum Physics क्वांटम फिजिक्स के बिना सूरज भी नहीं चमक सकता!

When one thinks of Quantum Physics, it strikes as a weird thing to imagine. However, the quantum idea that was proposed by Max Planck in 1900 and developed further by hundreds of his illustrious successors, has revolutionized the world. One can hardly imagine any part of life that is not governed by Quantum Physics.

For the common man, the Sun rises everyday and life routine begins. But the Sun that comes up everyday can not shine without Quantum Physics. In the interior of the Sun protons collide with each other with a very high speed of about 500 km/s at a temperature upto about 15 million degree centigrade. But this is not enough to fuse two protons to make a deuterium (heavy hydrogen) to make a further fusion. 

The phenomenon of Quantum Tunnelling (does not happen classically) allows 1 in 10^28 collisions to make one deuterium atom that can fuse further to generate helium atom (see the diagram below) and the produced energy. Since the Sun has 10^57 protons, the tunneling still produces 10^36 fusions every second and an energy of 4x10^26 Watts. This has been happening for the past 4.5 billion years and every star in the universe shines only through Quantum Tunnelling. Rest assured the Sun will continue to shine for the next billion years at least.

Courtesy: Fusion diagram from Ethan Siegel.