Every meteorite we saw falling down to earth

Hey, David Wendler here. At Datawrapper I’m responsible for design. In this edition of the Weekly Chart, I really wanted to create a map and found a wonderful dataset about meteorites.

What are meteorites? Short answer: little rocks that fell down to earth from outer space. In space a lot of objects are moving around: stars, planets, gas, dust, asteroids, comets, meteoroids. So collisions are only a matter of time — including collisions with our own planet. Our solar system and the Earth–Moon system have been shaped by so-called impact events several times over. On earth, collisions with asteroids have led to at least one mass extinction throughout history.

When talking about history, we’re talking about millions and billions of years ago. Luckily in recent history there haven’t been any impact events of that size. The collisions we humans get to see are usually with meteoroids, which are similar to asteroids but smaller. When parts of the meteoroid actually fall on the surface of the earth (instead of fully burning up after entering the atmosphere) these fallen pieces are then called meteorites.

This map shows every meteorite that has been seen by humans or measuring devices and where it fell down to earth. The symbols are sized by the weight of the meteorite and colored by the year it was observed. The two oldest recorded meteorites fell in Nogata, Japan in the year 860 and in Narni, Italy in 921. While there are several other very old collisions on this map, most of them were witnessed after 1800.

That, of course, doesn’t really represent how many meteorites actually fell each year. That number probably doesn’t change much over time — what changes is our ability to observe, document, and remember such events. That's easy to see in space as well: The location of meteorites on this map resembles a population map of where people are around to notice them. Many meteorites, including most of the old ones, are recorded in Europe, which has had high population density and observation capabilities for a long time. Many more meteorites must fall in the ocean, but there's no one to see them there.

As you can see there has been one very big one. It’s the Sikhote-Alin meteorite, and it fell in southeastern Russia in 1947. About 23 tons of rock came down to earth in fragments and the impact could be seen from 300 kilometers away!

That's it for this week! Enjoy your summer and watch the sky — you might see something falling.