NASA / SETI Institute |
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The wake of this Aurigid meteor blows in the wind at high altitudes, in a photo by
the SETI Institute's Kat de Kleer. Vibrations of the aircraft cause the wiggly track.
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Did they or didn't they? Meteors were supposed to light up the sky in a rare, brief burst at around 4:36 a.m. PT Saturday. Or so the experts said. In reality, the seldom-seen Aurigid meteor shower was showier but not quite as prolific as predicted. And the show peaked a few minutes early.
Frankly, even the experts didn't know exactly what to expect. Most years, the Aurigids are little more than a weak dribble, but astronomers suspected that this year would be special. This year, Earth was projected to plunge right through the narrow trail of debris left behind long ago by Comet Kiess, according to the SETI Institute's Peter Jenniskens, an astronomer specializing in meteors. It's that debris trail that's responsible for the Aurigid meteor shower.
"Only three people alive today are known to have seen this shower before in 1935, 1986, and 1994," Jenniskens wrote during the buildup to Saturday's peak. "After the 2007 encounter, the Aurigids will not be seen again in our lifetimes."
Jenniskens and other experts said sharp-eyed observers could average more than three meteors per minute under peak viewing conditions. That would far exceed the rate for the better-known (and more reliable) Perseid meteor shower two weeks ago.
But there were a few caveats: For example, the conditions for the Perseids were perfect because the moon's glare was totally absent. This time around, the moon was just past full and glowing like a headlight in the sky. Also, the Aurigids were expected to be active for less than an hour, between 4 and 5 a.m. PT (which was a bit too late in the morning for East Coast observers).
The biggest bugaboo was that meteor showers are not as predictable as clockwork, even though Jenniskens hopes that will be true someday. That's why Jenniskens and his colleagues were watching closely to find out if the shower matched their predictions.
Jenniskens even asked amateur stargazers to bring their cameras and camcorders with them and try to catch falling Aurigids in the act. His research group also sanctioned an effort known as the Aurigid Laptop Meteor Observation Project, which uses mouse clicks to keep track of meteor-spotting.
So what's the verdict? I drove 100 miles eastward early this morning to get out from under the Seattle area's overcast skies and check out the display for myself. As it turned out, I made it to Ellensburg in central Washington state just in time to catch the tail end of the show.
Perhaps the most amazing part of the experience was spotting a falling fireball in the skies ahead of me as I sped along Interstate 90, looking for a clear patch of sky at 4:04 a.m. PT. That was the first time I'd ever actually seen a meteor from the car, and it was a harbinger of what was to come.
By the time I parked my car along the side of a blacktop northwest of Ellensburg, it was already 4:20 a.m., and I was getting nervous about catching the peak time. It turns out that I should have been a little quicker out of the gate: When I started watching, I could see a bright meteor with a fizzy ionized tail every couple of minutes or so, but the count seemed to fall off a bit earlier than I expected. By 5 a.m., the show was definitely over. Soon afterward, dawn began breaking along the eastern horizon.
The bottom line was that the meteors were more impressive than I expected, but a lot sparser than the three-per-minute that had been projected. Of course, I also had to deal with that pesky moon as well as gauzy clouds floating across the night sky.
My assessment matched the initial reports coming in from elsewhere.
"Three observers saw 30 to 38 Aurigids each tonight in about one and a half hours under perfect conditions," German astronomer Daniel Fischer reported on the Meteorobs discussion forum. "There was one striking cluster of three within one second and close to each other, otherwise there were often long lulls."
Fischer said the peak seemed to come at about 4:15 a.m. PT rather than 4:36.
That meshed with the reports from Jenniskens and his colleagues, who were observing the meteor shower from two airplanes. They also reported peak activity at 4:15, at an estimated rate of 100 meteors per hour. That's better than the Perseids, but not as high as the most optimistic projections.
Seeing the flashes isn't the only way to detect meteor hits: Several research groups used radio equipment to monitor the signals created by the meteors' ionized trails. From New Mexico, observer Thomas Ashcraft recorded peak activity between roughly 4:15 and 4:45 a.m. PT (which translates to 11:15 to 11:45 GMT/UTC).
Space.com skywatching columnist Joe Rao, meanwhile, passed along other radio meteor reports indicating a brief but intense peak at around 4:32 a.m. PT - a few minutes earlier than expected.
Here's a list of still more radio meteor sites:
Did you actually snap a picture of the Aurigids as they fell? Feel free to send us your meteor masterpieces. If we get some good ones, we'll put them up in an online gallery. (SpaceWeather.com is already getting some great Aurigid imagery.)
If you're a meteor buff, you really ought to sign up for the Meteorobs list and make contact with your local astronomy club to find out what's coming up. The next big opportunities for shooting stars come in October with the Orionids, and in November with the Leonids.
Update for 9:15 p.m. ET Sept. 1: So was the meteor shower a bust? No. Maybe it wasn't as fantastic as some might have expected, and maybe the predictions of the peak were off by a few minutes. But all in all, the forecast for the reappearance of a meteor outburst that hasn't been seen in more than a decade was a tour de force. Weather forecasters should be so lucky. Congratulations to Jenniskens and his colleagues (who have added a crop of cool pictures to their Aurigid Meteor Shower Observing Campaign Web site).
