The most dramatic stellar show of the year – the 120-meteor-per-hour Geminid space shower – is peaking, and for Americans there’s a perfect shot at the action on Saturday and Sunday night.
With high clear skies dominating US weather into the weekend and moonrise coming late in the evening, the hours between 8 p.m. and midnight on Saturday and Sunday are likely to yield a perfect viewing opportunity. The show can also be seen all around the world, limited only by cloud cover, city lights, and the light of the moon. National Weather Service radar shows a storm system moving through the Rockies as the main nighttime viewing obstacle in the Lower 48.
The Geminids are the most prolific and noticeable star shower of the year, given both the hourly numbers and the density of the falling space dust, which averages the size of a pea. That means the Geminids one of only two annual meteor showers where a meteor could fall all the way to the ground to become a meteorite.
"The thing about the Geminids that makes them different is that [the debris that strikes the atmosphere] appears to be very dense," Bill Cooke, the head of NASA's Meteoroid Environment Office, told PC Magazine’s Evan Dashevsky.
The Geminids are named for their usual origin point near the Gemini constellation, but the shower is really the crash of the earth into a cloud of tailings from at least one asteroid, 3200 Phaeton, which measures three miles across. While Phaeton is ancient, its tailings didn’t surprise Earthlings until as late as 1862, when a British observer traced a shower of falling stars to a new radiant, or origin, near Gemini.
Notably, the Geminds material is denser than the comet-ice that forms most meteors. The denser material tends to create longer and brighter meteors, and increases the possibility of a particularly large speck falling all the way to earth.
At least for the next few centuries, the Geminids will continue to strengthen as the earth’s orbit gradually moves the planet closer to the core of Phaeton’s tail of dust.
Meteors were largely a mystery until the early 19th century.
Aristotle’s theory that the falling stars were bubbles of natural gas igniting in the atmosphere had lasted for over 2,000 years by the time Yale astronomer Denison Olmsted discovered in 1833 that the phenomenon involved objects entering the earth’s atmosphere and burning up at an extremely high rate of speed.
It took until 1867 for astronomers to figure out the connection between comets and meteors, as they linked the debris field thrown off by comet Tempel-Tuttle to the Perseids.
The Perseids, the Leonids and the Taurids are among other annual showers that delight stargazers. But around the world on a cold, clear late fall evening, the Geminids are kings among fallen stars.