How can I show pupils that most meteorites come from asteroids?

Question

Accepted Answer

Use orbits calculated from filmed fireballs, which trace back to the asteroid belt, plus spacecraft samples from asteroids Itokawa, Ryugu and Bennu that match meteorites.

Pupils often learn that meteorites come from asteroids, but it is more powerful to show them how scientists know.

Evidence 1: fireball orbits. Since the Příbram meteorite was photographed falling in the Czech Republic in 1959, scientists have calculated the orbits of dozens of meteorites before they hit Earth. Almost all have orbits that reach back into the asteroid belt between Mars and Jupiter. Show pupils a diagram of these orbits and ask them to describe the pattern.

Evidence 2: matching colours. Telescopes measure how asteroids reflect different colours of light, called their spectra. These match meteorites in the laboratory: stony S-type asteroids resemble ordinary chondrites, dark C-types resemble carbonaceous chondrites, and V-types match meteorites from Vesta.

Evidence 3: samples from asteroids. Japan's Hayabusa mission returned grains from asteroid Itokawa in 2010. They matched LL ordinary chondrites. Hayabusa2 returned samples from Ryugu in 2020, and NASA's OSIRIS-REx returned samples from Bennu in 2023, both resembling carbonaceous chondrites.

Evidence 4: the age. Most meteorites are about 4.5 billion years old, consistent with leftover building blocks from small bodies that formed early.

Activity. Give groups evidence cards and ask them to build an argument for where meteorites come from, as a scientist would. Then introduce the exceptions: a few hundred from the Moon and Mars. Discuss how those were identified differently.

This approach models how scientific conclusions rest on several independent lines of evidence.

How can I show pupils that most meteorites come from asteroids?

More about for teachers