You are here


August 25, 2015

Odd things sometimes fall from the sky — from mud to fish and toads. And 150 years ago today, a piece of Mars fell on the Indian village of Shergotty. Around 9 a.m., witnesses heard a loud boom. A few minutes later, they saw an 11-pound rock fall to the ground. It was soon identified as a meteorite. But it took more than a century to identify its Martian origin.

Scientists have confirmed more than a hundred Mars meteorites. They’ve done so by examining tiny bubbles of gas inside the rocks. The ratios of different forms of oxygen and other elements in those bubbles match those measured in the Martian atmosphere by several Mars landers.

The Shergotty meteorite formed as recently as 165 million years ago, when molten rock from a Martian volcano cooled and hardened. The rock probably formed near Mars’s equator, which is the site of the planet’s most recent volcanic activity.

The meteorite is made mainly of silicon dioxide and iron oxide — the “rusty” mineral that gives Mars its orange color. It also contains tiny amounts of water, suggesting that it spent part of its lifetime in a wet environment.

A few million years ago, an asteroid slammed into the Martian surface. The impact was powerful enough to blast the Shergotty meteorite and other bits of the Martian crust out into space. Most of these rocks are still orbiting the Sun. But at least one made it to Earth — where it fell from the sky 150 years ago today.


Script by Damond Benningfield, Copyright 2015

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.