What is the Sun?

Overview

The Sun is the star at the heart of our solar system, a massive ball of plasma that provides the energy sustaining life on Earth through nuclear fusion.

  • Diameter: 1.39 million km
  • Distance from Sun: 0 km (it's the center!)
  • Mass: 1.989 x 10³⁰ kg
  • Rotation Period: ~25 days (equator), ~35 days (poles)
  • Age: 4.6 billion years
The Sun captured by SDO

Image credit: NASA/GSFC/SDO

Details

Composition: Primarily hydrogen (73%) and helium (25%), with traces of heavier elements like oxygen and iron.

Structure: Layers include the core (where fusion occurs), radiative zone, convective zone, photosphere, and corona.

Activity: Produces solar flares and sunspots, affecting space weather and Earth's technology.

Exploration: Studied by spacecraft like SOHO and Parker Solar Probe, which approach closer than ever before.

Fun Fact: The Sun accounts for 99.86% of the solar system's total mass.