![tungusta meteorite tungusta meteorite](http://olkhov.narod.ru/tp2007_pristan_lebedeva.jpg)
Stalks from it to the ecliptic plane are at 1-month intervals. The thicker line is the vernal equinox direction. Lines on the ecliptic place are 1 astronomical unit (Sun-Earth distance) apart. The shower’s radiant is near the star Zeta Tauri, the tip of the Bull’s southern horn, which at the end of June is not far south and west of the Sun. The Beta Taurid meteor shower peaks on June 28 or 29 it is caused by one of the debris streams from that comet, and is a daylight shower, detected by radar, because it is in the out-going part of the orbit and therefore, like the Tunguska object, hits the sunward side of Earth. Johann Encke was not one of its independent discoverers, but was the mathematician who in 1819 by laborious calculations proved that several previous comets were the same one. Plausibly, though not certainly, it was a fragment of 2P Encke, the periodic comet that, because of the shortness of its orbit, returns most frequently – every 3.3 years since its first discovery in 1786. Though no parts of it and no crater have been found on the ground, it counts as the largest impact in recorded history – not as large as the unrecorded strikes that caused Meteor Crater or, millions of years ago, the Chicxulub buried crater and the end of the Cretaceous age. Was it a comet, a small asteroid, even a black hole passing through the Earth? Calculations are that an object maybe 50 meters wide exploded maybe 100 kilometers up in the atmosphere. Not till 13 years later did scientists get to the remote region and gather evidence of what had happened, so there is much uncertainty. There is no town nearby the event got its name from the Podkamennaya Tunguska, Stony Tunguska river, which got its name from the Tungusic-speaking peoples of the region, and which like the Nizhnya Tunguska, Lower Tunguska, joins the great Yenisei to flow into the Arctic Ocean. The trees of the taiga forest were flattened radially outward over an area of nearly a thousand square miles. On 1908 June 30, at about 7:17 by local Siberian time, the native people (Buryat, Evenki, and others) and Russian settlers of a thinly populated region northwest of Lake Baikal saw the sky split by a long bluish flash almost as bright as the low morning Sun, followed by noise like artillery, then shock waves that knocked them off their feet and that reached, hours later, as far as Britain in one direction and Washington D.C. In this picture, the streak for the Tunguska object is guessed, not calculated. But here’s something about the event of 112 years ago, which Asteroid Day commemorates. I failed to celebrate it because what I tried to put together about the asteroids had problems, after much work. Let’s pretend we’re still in June, for two reasons: because we wish we weren’t already into the latter half of yet another year (and the month of my birthday), and because the last day of June was Asteroid Day.