Meteors, even bright ones, happen all the time. But every now and then a truly bright fireball is witnessed by so many people that the event makes the news. And, thanks to the speed and ubiquity of the Internet, such news travels fast.
Case in point: On June 23rd a spectacular fireball lit up the skies of southeastern Arizona at 9:22 p.m. local time. Given the favorable timing, it was widely seen. Brightness estimates ranged from magnitude -9 to an astounding -27 (as bright as the midday Sun).
Some observers noted that the interloper exploded and fragmented — technically, making this a bolide. Widely seen bolides make meteorite hunters salivate. If sightings from the ground are accurate enough, a little trigonometry can reveal the object's true flight path and, sometimes, a cosmic pot of gold waiting at its end. For example, it only took a few eyewitness accounts of a spectacular meteoric entry over Sudan last October to pinpoint the fall zone of fragments that fell to Earth afterward.
Coincidentally, a lot of meteorite hunters live in Arizona, and June 23rd's sky show was a call to action for these modern hunter-gatherers. Now, the Arizona desert is a pretty big place that gets especially hot and inhospitable this time of year. And the seasonal monsoons that inundate this region each summer can quickly turn the dust-dry landscape into out-of-control slurries of mud and water. Moreover, when a space rock fragments in the atmosphere, it can drop pieces over a miles-long oval area (known as a strewnfield) along the entry path.
But a small group led by Jack Schrader still managed to track down one of the fallen sky-stones soon after its arrival on Planet Earth. As Schrader reported July 4th to an online list of meteorite aficionados, "I recovered a 155.6 gram stone at 6:20 p.m. on Thursday, June 25, which is 44 hours and 58 minutes after the fireball was sighted." It's a beauty, as Schrader's picture here shows. More than a half dozen pieces have been recovered so far.
It's the first recovered fall in Arizona in 97 years. Schrader explains, "I was able to very quickly zero in on the area with the help of numerous phone calls and eyewitness reports which were all thoroughly investigated with follow-up visits." Schrader was thorough, but he also had an advantage: "I was born and raised in this part of Arizona, and my intimate knowledge of the country, the terrain, the trails, and back roads has proved invaluable in my search."
So where did the meteorites fall? Schrader isn't saying, and his secrecy has led to cries of "Foul!" from others who want to join the hunt. But Schrader is standing firm. "The site is akin to a pristine archaeological site at the moment," he said in an email to me, "and we have to be constantly on watch for those who would love nothing more than to 'pot hunt' the site for something for their shelf at home."Schrader has already turned over some of his finds to meteorite specialists at the University of Arizona, as these pictures show.
Meanwhile, another eye-popping fireball appeared on June 26th over southeastern Pennsylvania and northern Maryland. However, this arrival came in the wee hours (about 1:10 a.m.), limiting the number of eyewitnesses. Fortunately, though apparently not as bright as the Arizona event, it was captured in a surveillance video at the York (Pennsylvania) waterworks. The few frames indicate a generally west-to-east track, toward the nearby Delaware border.
It was an especially lucky night for Mike Hankey of Freeland, Maryland. An amateur astronomer and budding astrophotographer, Hankey was out past midnight shooting the Andromeda Galaxy (M31) through his Orion 90-mm f/10 refractor. He'd gone indoors after setting up a series of 3-minute exposures. But he scrambled outside after hearing the fireball's thunderous boom.
One of the images stored in his Canon 20Da camera told an amazing story. The fuzzy nucleus of M31 was centered in the frame, but a set of overexposed streaks has crossed one corner. The next morning, hearing news reports about the early-morning visitor from outer space, Mike posted the image on his website.
Soon the meteorite community was buzzing with word about Mike's shot in the dark. In most minds, he fortuitously had captured incandescent fragments of the space rock in the split second they crossed his camera's field of view. The time is right (1:06-1:09 a.m.), and the sky location and direction of flight are consistent with the York video — though some have questioned whether an about-to-land aircraft caused the streaks instead.
No matter. As I write this, meteorite-hunting veterans (and more than a few newbies, Hankey among them) have fanned out along the Maryland-Pennsylvania-Delaware border in the hope of finding a black-singed rock fresh from the depths of interplanetary space.