How Energy is Produced in the Sun: Life for Solar System

The Sun is the heart of the solar system and the source of energy for all the planets revolving around it. But how does it get this amount of energy to support the planets like our earth or even bigger than it by multiple times?

What happens at the core of the sun

The sun is mainly composed of elements like hydrogen and helium which are in plasma state. The sun’s core has really high temperature and pressure, which is the reason the nuclei present there, get separated from their electrons. The process that occurs thereafter is called nuclear fusion.

My friend Bhautik Wondered What is the Color of Sun

Nuclear fusion at the centre of the sun:

The sun is a comparatively cooler star than others, who have a core temperature of above 108 K. But the sun has less than 107 K at the core. Hence, fusion occurs by proton-proton cycle.

  • 1H + 1 H  → 2 H + e + + υ
  • 2H + 1H  → 3 He+ ϒ
  • 3He+ 3He → 4He + 2 1H
  • 4 1H→ 4He + 2e+ + 2 υ + 2 ϒ

 It is the proton-proton cycle.

Sun reaction
Nuclear Fusion

In this process, four hydrogen nuclei combine to form a helium nucleus. 26.7MeV energy is released in this process. Here, hydrogen is the fuel that burns into helium releasing energy. According to an estimation, it radiates more energy each day than the world uses in a year. It’s estimated to have been radiating energy for last 4.5 X 109 years. It will continue until all of its hydrogen content gets finished. The present amount of hydrogen in the sun can run it for the next 5 billion years! So, the sun’s not going anywhere for the next 5 billion years.

During fusion, radiant energy is released from the core. This radiant energy takes 150,000 years in the core to come to the surface of the sun. And then it takes only 8 minutes to reach the earth.

A question may arise that as two protons are positively charged, so they will repel each other. So, how could they fuse together to form helium? The answer is that the high temperature and pressure in the core enable them to come much closer than what they could have been, under normal circumstances. This coulomb repulsion becomes more and more obstructive as the atomic number increases. It needs higher temperature for heavier elements to fuse together. The outward pressure created by the fusion reactions gets balanced by the inward gravitational pull of all the gases that encompass the core of the star.

In hotter stars with core temperature above 108 K , proton-carbon cycle occurs.

1H + 15N    → 12 C + 4 He

Sun Image By NASA/SDO (AIA) –, Public Domain,

have you wondered why does Sun Has dark spot

Interesting facts about energy of the Sun:

  • One part in 2 billion of sun’s energy reach the earth.
  • The process that creates energy in the sun, nuclear fusion, is the same process that induces the blast through a Hydrogen bomb.

Author: Som Abhisek.

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Bhautik Kapadiya

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