The Evolving Universe

Smithsonian Institution

The Sun

Sun image

Credit: NASA/Lockheed Martin/SAO

View/Download Full Resolution Image

View/Download Poster (PDF)

You are here and now - but the distant past is all around you.

Our Sun and Earth formed about 4.6 billion years ago from the cosmic gas and dust of ancient, long-gone stars.

Our Sun is only one of 100 billion stars in our galaxy. Without it, life on Earth would not be possible. What we know about our Sun serves as the foundation for what we understand about distant stars.

Over its lifespan, the Sun will convert only one-tenth of one percent (0.1%) of its mass into energy. Based on observations of other stars, astronomers estimate that half of the remaining mass will blow off into space after our Sun becomes a red giant about 5 billion years from now. The mass that is left will shrink, becoming a very dense dwarf star that will glow dimly for billions more years.

  • Distance from Earth: 8.3 light minutes
  • Size: 1.39 million km
  • Telescope: Solar Dynamics Observatory
  • Light: Extreme Ultraviolet (30.4 nm)