Tunguska

When I was in college, I took an introductory astronomy course and wound up writing a short (5 page?) paper on Tunguska. I believe I concluded, by process of elimination, that it must have been caused by a mini black hole. Hey, it's cooler to think about mini black holes than about comets or meteors!

Be that as it may, I remain intrigued by the event. National Geographic has the latest interesting development: Crater From 1908 Russian Space Impact Found, Team Says. The corollary is that there was no mini black hole, just your ordinary "cosmic body":

Gasperini's team says that the basin's unusual shape is the result of a fragment thrown from the Tunguska explosion that plowed into the ground, leaving a long, trenchlike depression.

"We suggest that a 10-meter-wide [33-foot-wide] fragment of the object escaped the explosion and kept going in the same direction. It was relatively slow, about 1 kilometer a second [0.6 mile a second]," Gasperini said.

The lake is located along the most probable track of the cosmic body, he added, which likely made a "soft crash" in the marshy terrain.

Still, there's hope for us mini black hole fans:

William Hartmann, senior scientist of the Planetary Science Institute in Tucson, Arizona, said the new findings are compelling but do not address all of the lingering questions about the event.

"It's an exciting result that might shed new light on the Tunguska explosion," he said. "Certainly it warrants new studies of the area.

"But it raises a question in my mind: If one large fragment hit the ground, we would normally expect thousands of smaller fragments also to hit the ground along the path, and many searches have failed to find such meteorite fragments. So, why no smaller pieces?"

Go, Mini Black Hole!