News since last weekend of a meteor that exploded and fell on Chelyabinsk in central Russia, causing major damage, has been a huge topic. About 17 meters across, 10,000 tons, entering the atmosphere at 18 km per second—the released energy is said to be more than thirty times the Hiroshima atomic bomb. We are reminded again that nature—or the cosmos—operates on a scale far beyond imagination. For astronomy fans, that is part of the great appeal.
Footage of this fall seems plentiful. Videos of meteors and comets are not rare, but filmed meteorite falls are unusual—especially in bright daylight, perhaps for the first time. Much of it was captured on dash cams; in Russia, where traffic disputes are common, dash cams prove their worth and many cars have them. This fall will likely be replayed in planetariums nationwide alongside meteors and comets.
At the To Nichi Tenmonkan (later Mainichi Tenmonkan) in the To Nichi Kaikan—building of Tokyo Nichi Nichi Shimbun, predecessor of The Mainichi Newspapers—Tokyo's first planetarium opened in 1938 (Showa 13). People interested in astronomy formed a club and held lectures by experts. Among precious materials collected by Seiji Ogawa of Hoshi no Kai is a booklet with full transcripts of talks such as "On Celestial Discovery" and "On Novae and Solar Explosions." There was also an astronomical society with similar lectures; stenographic records appeared as supplements to the bulletin.
A society lecture in November 1943 was given by Dr. Shigeru Kanda, engineer at the Tokyo Astronomical Observatory, on "Observation and Study of Meteors." He explained that meteors appear relatively often around August and November and discussed meteor showers. Meteors and meteorites differ in origin from comets and asteroids, but interest in space never fades; many people must have attended.
However, aside from Ogawa's booklets, little material survives on the To Nichi (Mainichi) Astronomical Club and Mainichi Astronomical Society, so details are unclear. Lectures may also have covered meteorites as a cause of dinosaur extinction and the 1.5 km wide, 170 m deep Barringer Crater in Arizona formed by a huge meteorite impact.