Friction with the air then heats and annihilates the dust in a burst of light, and the result is a shower of meteors.Because of the direction from which the dust is coming, these meteors appear to radiate from a constellation called Leo.
But the wartime radar screens had also spotted other puzzling radio-frequency phenomena: signs perhaps of cosmic rays, perhaps of meteors.
Dr Paczynski is now urging his colleagues to extend their searches to the whole sky, to look for anything and everything whose brightness changes.Trawling the whole of the night sky with an optical telescope is challenging because it is so complicated there are billions of stars and galaxies to contend with, not to mention meteors, artificial satellites and aeroplanes.
Early research involved a colleague lying in a deckchair in the night-time open air with a piece of string to measure the meteors, while he observed electromagnetic signals on a cathode-ray tube in a nearby hut.
One, which should be visible from much of North America, is predicted to reach 2,000 meteors per hour just over one every two seconds.
In particular, he calculated that the Perseid meteors are remnants of Comet 1862 III and the Leonids of Comet 1866 I.
In 1932 Öpik published a paper examining what happened to meteors or comets scattered to very large distances from the Sun, where they could be perturbed by random passing stars.
His work on meteors enabled him to correctly predict the frequencies of craters on Mars many years before these could be ascertained.
The instruments also can add such details as horizon scenes, the Milky Way, nebulae, comets, meteors, and various reference lines and scales used for teaching descriptive astronomy and celestial navigation.
The composition of the meteorite fragments indicates that the crater was caused by a rare metallic meteorite (only 10 percent of meteors are metallic, most being stony) probably formed by the breakup of a planetoid.
The great Leonid meteor shower of Nov. 12, 1833, in which hundreds of thousands of meteors were observed in one night, was seen all over North America and initiated the first serious study of meteor showers (see meteoritics).
