FIRST PERSEIDS OF 2013: Earth is entering a broad stream of debris from comet 109P/Swift-Tuttle, source of the annual Perseid meteor shower. Although the shower won’t peak until August 12-13, when Earth hits the densest part of the stream, the first Perseids are already arriving. “Despite poor weather over our network of meteor cameras, we detected three Perseid fireballs on July 30-31,” reports Bill Cooke, head of NASA’s Meteoroid Environment Office. He made this plot showing the orbits of the meteoroids:

In the diagram, the green lines trace the orbits of Perseid meteoroids. All three intersect Earth (the blue dot). The orbit of the parent comet is color-coded purple. An inset shows one of the fireballs shining almost as brightly as the Moon: video.

The shower is just getting started. Rates should remain low for the next week as Earth penetrates the sparse outskirts of the debris stream, then skyrocket to ~100 meteors per hour as the calendar turns to the second week of August.

fr/spaceweather.com