Asteroid Day, officially started in 2015, is an educational effort designed to bring scientists, artists and concerned citizens together to raise awareness of the hazards of asteroid impacts and build support for effective solutions.
Asteroid Day coincides with the anniversary of the most powerful measured asteroid impact with Earth in history, detailed a little farther down in this article. Estimates vary, but such collisions may happen roughly once every several hundred to 1,000 years. https://www.sciencenews.org/blog/science-ticker/asteroid-day-chance-learn-about-space-and-plan-disaster
If you want to start a conversation with anyone in the asteroid business all you have to say is Tunguska,” says Don Yeomans, manager of the Near-Earth Object Office at NASA’s Jet Propulsion Laboratory JPL. “It is the only entry of a large meteoroid we have in the modern era with first-hand accounts.”
While the impact occurred in ’08, the first scientific expedition to the area would have to wait for 19 years. In 1921, Leonid Kulik, the chief curator for the meteorite collection of the St. Petersburg museum led an expedition to Tunguska. But the harsh conditions of the Siberian outback thwarted his team’s attempt to reach the area of the blast. In 1927, a new expedition, again lead by Kulik, reached its goal.
“At first, the locals were reluctant to tell Kulik about the event,” said Yeomans. “They believed the blast was a visitation by the god Ogdy, who had cursed the area by smashing trees and killing animals.”
It is estimated the asteroid entered Earth’s atmosphere traveling at a speed of about 33,500 miles per hour. During its quick plunge, the 220-million-pound space rock heated the air surrounding it to 44,500 degrees Fahrenheit. At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs.