They came from outer space--and you can have one! Genuine meteorites are now on sale in the Space Weather Store. | | |
VOYAGER 1 HAS LEFT THE SOLAR SYSTEM: Researchers have long waited for one of the Voyager probes to leave the solar system. In a surprising turn of events, NASA announced today that Voyager 1 entered interstellar space a whole year ago! This event sets in motion a new era of exploration of the realm between the stars. Congratulations to the Voyager team! [full story]
RUSSIAN AURORAS: Earth is entering a stream of medium-speed (500 km/s) solar wind. While this is not yet causing a geomagnetic storm, the action of the wind is sufficient to ignite bright auroras around the Arctic Circle. Valentin Jiganov sends this picture taken on Sept. 13th from Khibiny in the Murmansk region of Russia:
Such displays could spread around the Arctic Circle tonight. NOAA forecasters estimate a 45% chance of polar geomagnetic storms on Sept. 13th as the solar wind continues to blow. Aurora alerts: text, voice.
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METEOR OUTBURST? European sky watchers have witnessed an outburst of September epsilon Perseid meteors. "The outburst occurred around UT midnight on Sept. 9-10," says Bill Cooke, head of NASA's Meteoroid Environment Office. "During a two hour period, meteors appeared at a rate equivalent to ~50 per hour (ZHR). We did not see the outburst in North America because it was still daylight at the time."
NASA all-sky cameras have been recording epsilon Perseid fireballs for days, albeit at a much lower rate than what the Europeans saw. The shower has been active since early September, allowing Cooke's team to calculate orbits for more than a dozen meteoroids:
In the diagram, orbits are color-coded by velocity. Epsilon Perseid meteoroids hit Earth's atmosphere at a "blue-green" speed of about 62 km/s (139,000 mph). According to NASA data, the debris stream appears to be rich in fireball-producing meteoroids.
The epsilon Perseid shower peaks every year around this time, but the shower is not well known because it is usually weak, producing no more than 5 meteors per hour. In 2008 the shower surprised observers with an outburst five times as active, and this year the shower may have doubled even that. Clearly, the epsilon Perseid debris stream contains some dense filaments of material that Earth usually misses but sometimes hits.
No one knows the source of the September epsilon Perseid meteor shower. Whatever the parent is, probably a comet, its orbit must be similar to the green ellipses shown in the orbit-map above. As NASA cameras continue to gather data on this shower, orbital parameters will become more accurately known, possibly leading to a match.
Meanwhile, sky watchers should be alert for more epsilon Perseids in the nights ahead. The shower is waning but still active and more outbursts are possible.
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[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]
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