Let’s face it, our solar system is a messy place. The gravity of Jupiter has a nasty habit of flinging things in all directions, and multiple interactions between a space rock and planets and other small objects can lead to something migrating all the way in toward Earth. 

There is a class of objects called Near-Earth Asteroids or Near-Earth Objects (NEOs) that have orbits that cross Earth’s orbit. This doesn’t mean they are going to hit us, and when I say “cross Earth’s orbit”, I don’t mean the orbits intersect. That crossing could be above or below our position, allowing us to get close but never actually collide. These NEOs include rocky objects like Bennu and Ryugu, and also metal-rich objects that some folks would like to one day mine. 

New observations of two NEOs show that asteroids 1986 DA and 2016 ED85 are about 85% metal and 15% pyroxene. This work is published in the Planetary Science Journal and was led by another PSI researcher, Juan Sanchez.

Like that main-belt comet, these space rocks did not start where they are now. According to Sanchez: Analysis of their orbits allows us to trace their origin to a region in the outer asteroid belt where the largest metal-rich asteroids reside.

If you have a metal meteorite in your knickknack collection, it too started in the outer asteroid belt… probably.

More Information

PSI press release

“Physical Characterization of Metal-rich Near-Earth Asteroids 6178 (1986 DA) and 2016 ED85,” Juan A. Sanchez et al., 2021 October 1, The Planetary Science Journal