Diogenite from Vesta | NWA 7831 165.2 g

Vesta is the largest and brightest asteroid in the asteroid belt and the second largest body overall (after the dwarf planet Ceres), with an average diameter of about 525 km (326 miles). That is pretty close to the size of the State of Colorado. Vesta was discovered by the German astronomer Heinrich Wilhelm Olbers in 1807.

A couple of billion years ago two massive impacts ejected part of Vesta’s mass and some of that material landed here on Earth as HED (howardite, eucrite, and diogenite) meteorites. It’s astonishing to consider that when you look at photographs of Vesta, or eve through a powerful telescope, the actual craters from which the HED meteorites were blasted out can easily be seen, such as Rheasilvia which is over 300 miles wide. So, you could hold one of these HED meteorites in your hand, look at a photo of Vesta, and say to yourself: This came from right there!

While it is true that the majority of all know meteorites originated on asteroids, which don’t know which ones — apart from the HED Vesta meteorites. There are only six positively identified bodies in the entire solar system (so far) from which we have, here on Earth, physical samples for study. They are: our own Earth, the Moon, Mars, comet Wild 2, asteroid 25143 Itokawa, and Vesta. NASA’s Stardust mission collected a small amount of material from Wild 2; the Japanese Hayabusa probe collected regolith particles from Itokawa. But Vesta is the only identified asteroid from which meteorite collectors can acquire a specimen. All known meteorites from Vesta fit into the achondrite class — meteorites without chondrules — and are collectively known as the HEDs: howardites, eucrites, and diogenites.

Why do we find the Vesta meteorites so fascinating? Well, apart from having a known origin point, the meteorites that traveled here from Vesta demonstrate that the solar system is, or was, active — geological processes have been at work out there, shaping worlds. And we have the evidence of it right here, as Vesta’s intriguing HED meteorites.