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Science Frontiers ONLINE No. 94: Jul-Aug 1994 |
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Beware the ides of june -- and the rest of the month, too!
Three astronomical events, all within the short span of written human history, lead J. Hartung to warn us that June is a dangerous month for earthlings.
June 18, 1178. On the moon.
"...just after sunset, it was reported by at least five men that the 'upper horn of a new moon split and from the division point fire, hot coals, and sparks spewed out.'"
These observations have been interpreted as eyewitness accounts of the impact on the moon that gouged out the crater named Giordano Bruno, 20 kilometers in diameter.
June 30, 1908. Siberia.
"On the morning of June 30, 1908, a tremendous explosion deep in the Siberian taiga near the Tunguska river caused trees over an area of 40 km in diameter to be flattened in a radial pattern and produced a pressure wave in the atmosphere which circled the Earth."
June 17-27, 1975. On the moon.
"...an unusual meteoroid 'storm' was detected by the array of seismometers placed on the moon during the Apollo missions. The peak impact rate on the moon of 0.5-to-50-kg objects was about 10 times the normal background during this interval. Such a high rate was not recorded at any other time during the 8-year operation of the Apollo passive seismic network."
Hartung links all three events to the comet Encke and the closely related Taurid Complex of naturally occuring space debris. Some chunks in this wide stream of space debris are measured in kilometers and, if they hit the earth, would far outclass the infamous Siberian projectile of 1908.
(Hartung, Jack B.; "Giordano Bruno, the 1975 Meteoroid Storm, Encke, and Other Taurid Complex Objects," Icarus, 104:280, 1993.
Comment. Since we will not mail this issue of SF until the first week in July, you are safe for another year (?) if you are reading this!