…and where to find them.
This analysis was inspired by a set of talks by Mike Brown of Caltech on small bodies in the Solar System (these are available as part of his course on The Science of the Solar System on Coursera). He speaks with passion about these fascinating objects and how they tell an intriguing story about the formation of our Solar System. Most of the science you’ll meet within this blog comes either from this course or else an excellent book, Physics and Chemistry of the Solar System by John Lewis.
The data come from NASA (where else) and contains information on over 35,000 meteorites up to end 2015. In terms of munging, the data is:
rescaled for meteorite mass in kilogrammes
locations (in longitude/latitude) are attributed to their continents (using a function from Andy South)
some meteors were missing geographical coordinates, an attempt was made to find these and fill them in. This worked for the Nunatak and Yamato fields, both in Antarctica
cleaned to remove remaining incomplete records (6463 of them)
meteorite classes are grouped together. For example, Iron IIIAB, Iron IAB, Iron IC, …. are all just called Irons.
meteorites are further grouped into Chondrite, Achondrites, and Irons (with some subclasses of achondrite based on metal content as there are so many achondrites)
we delete meteorites with a mass of 0kg. There are a handful of these and they mess up our analysis somewhat and are obviously physically impossible
there are a large number (6164) where the (longitude, latitude) is given as (0\(^{\circ}\), 0\(^{\circ}\)). These get dumped in the Atlantic Ocean, just off the coast of Ghana (see the bright red dot in the middle of the map). The name of the meteorite should help locate them, at some point I’ll do something about that. Lots of them are in Antarctica.
First, let’s look at where meteorites have been found. The map below shows our meteors. The circle sizes correspond to meteor mass (though you have to zoom in a bit to appreciate the different sizes), the colour indicates the year of discovery. You can click on circles to get these details, as well as the meteor name. To avoid map navigation being tediously slow, only the heaviest meteorites are initially shown, but by clicking the top right legend you can include more.