Halley's Comet

Halley's Comet is the most famous comet in the sky. It is named after Edmond Halley, a scientist from long ago. He figured out that the comet comes back every 76 years. That means most people see it only once in their lives. The last time it passed by was in 1986.

What Is a Comet?

A comet is like a giant dirty snowball. It is made of ice, dust, and rock. When a comet gets close to the Sun, it heats up. The ice turns to gas and forms a glowing tail. The tail can be millions of miles long.

A handwritten letter from Edmond Halley, the scientist who studied comets.
A handwritten letter from Edmond Halley, the scientist who studied comets. (Edmond Halley (1656–1742) / Wikimedia Commons)

A Long Journey

Halley's Comet has a very long orbit around the Sun. It travels out past Neptune before coming back. People have seen it for thousands of years. Ancient records from China mention it. It will return in the year 2061.

Fun Facts

  • Halley's Comet was shown on the Bayeux Tapestry in 1066.
  • Its core is only about 9 miles long.
  • The comet travels about 157,000 miles per hour.

Did You Know?

The writer Mark Twain was born when Halley's Comet appeared and died when it came back 74 years later.