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Asteroid Day: Your reminder to look up and watch out
On 30 June 1908, in middle of no where Siberia, a fairly large object streaked through the sky and exploded over the Eastern Siberian Taiga. This air blast is estimated to have flattened 80 million trees, killed countless reindeer and 3 humans, and created a shock wave through the atmosphere that was detected all around the world.
As a reminder that space rocks kill, Asteroid Day was created as a new, UN-sanctioned, yearly event held on the anniversary of that bad day in Siberia. It is a day on which scientists and science communicators work to remind everyone that rocks can still fall out of the sky and kill.
Tunguska, with its 50–200m diameter, isn’t the only human observed major event. For many of you reading now, the 2013 event in Chelyabinsk was a wake up call to just how dangerous a 20m space rock can be. Streaking through the early-morning sky and observed in security and dashboard cameras, this event included an explosion above the ground, a massive shock wave, and a fair amount of destruction. We are pleased to share that no reindeer are known to have been harmed and no deaths were reported.
Both these objects exploded in the air, most likely due to the expansion of volatiles (ices and other things that go to gas). While we’re pretty sure the Chelyabinsk object would be called an asteroid…
