MEPX
Chapter 10 of 12All chapters
  1. 1The scale of things
  2. 2The Sun
  3. 3The rocky planets
  4. 4The giant planets
  5. 5Moons
  6. 6Asteroids and comets
  7. 7Gravity and orbits
  8. 8Light and distance
  9. 9Stars and their lives
  10. 10Galaxies
  11. 11The expanding universe
  12. 12Observing for yourself

Chapter 10 of 12

Galaxies

Where we sit in the larger structure.

The Milky Way

Our solar system is one of hundreds of billions of systems in the Milky Way, a barred spiral galaxy we see edge on as a band across the sky. A supermassive black hole sits at its centre.

  • One orbit of the galaxy takes the Sun about 230 million years.
  • Andromeda is the large galaxy next door and is heading our way.

Larger still

Galaxies group into clusters and clusters into superclusters, strung along filaments with vast voids between them. That web is the largest structure known.