The building of Stonehenge and other megalithic monuments may have been prompted by "the most massive meteor stream in the inner planetary system," according to researchers in Ireland and Australia. The Taurid meteor stream formed over the past 20,000 to 30,000 years, and every 2,500 to 3,000 years it forms a particularly impressive display when its core crosses the Earth orbit. The Taurids stream consists of the dust and celestial debris left by comet Encke, thought to be a remnant of a much larger comet. When the stream's orbit passes close to Earth, stray particles burn up in our atmosphere to create shooting stars. "There are lots of very large pieces within the stream that occasionally produce very notable fireballs," says Gary Kronk, a Missouri-based science writer.
     Unlike better known meteor showers such as the Leonids, which will streak in the sky this month at around 37 miles per second, the Taurids move at the slower speed of 17 miles per second. And: "Because the Taurids are also spread out in space, the Earth takes a week or two to pass through them, unlike more tightly bunched phenomena where passage can take just a few hours," says Bill Napier, a research astronomer with Ireland's Armagh Observatory.
     Duncan Steel, is an Adelaide, Australia-based researcher and expert on comets and meteors. He points out that the Taurids have split into two separate branches, which pass the Earth with a gap of a few centuries. Every 2,500 to 3,000 years or so, the core of the Taurid stream passes near Earth and produces much more intense meteor showers for a few centuries. "It is about 1,000 years before the next such epoch is due," said Steel, "And I have suggested that megalith building, for example Stonehenge, was prompted by such events in the past, when the sky started going wild, repeatedly, every year," added the researcher.
     There are several other meteor showers associated with the Taurids, including daytime showers which can be picked up by radar. Steel and Napier have suggested that the daytime Beta Taurids are the source of the Tunguska object that flattened thousands of square miles of Siberian forest on June 30, 1908.
     (Editor's comment: More than one reputable author has speculated that, when elaborate multiple burials were replaced by more simple individual burials in complex megalithic landscapes, it marked a shift in religiosity away from the cthonic [the earth and underground gods] to the celestial.)

Source: National Geographic (7 November 2003)