What Is the Sun?
The Sun is a star, located at the centre of our solar system. It contains over 99.8% of the solar system’s total mass, meaning everything else — planets, moons, asteroids — makes up less than 0.2%.
It is primarily made of:
Hydrogen (~74%)
Helium (~24%)
Trace heavier elements
How the Sun Produces Energy
At the Sun’s core, temperatures reach about 15 million °C. Under this immense heat and pressure, hydrogen atoms fuse together to form helium in a process called nuclear fusion.
This process:
Releases enormous amounts of energy
Produces light and heat
Has powered the Sun for over 4.5 billion years
Without nuclear fusion, the Sun would collapse under its own gravity.
Layers of the Sun
The Sun has several layers:
Core – where fusion happens
Radiative zone – energy slowly moves outward
Convective zone – hot plasma rises and falls
Photosphere – the visible “surface”
Chromosphere & corona – outer atmosphere
The corona can be hotter than the surface — a mystery scientists are still researching.
Solar Activity & Space Weather
The Sun is not calm. It produces:
Sunspots (cooler, darker regions)
Solar flares
Coronal mass ejections (CMEs)
These events can:
Disrupt satellites
Affect GPS and radio signals
Create auroras on Earth
Key Takeaways
The Sun is a star, not a planet
Nuclear fusion powers the solar system
Solar activity directly affects Earth