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A 75 ton meteorite wakes up California & Nevada
I read about this meteorite waking up folks in California and Nevada a couple days ago but I had no idea it was a 75 ton or 154,300 pound monster. This article says it released 5-kilotons of energy or a third as much as the bomb the American Empire dropped on Hiroshima. Meteorites found in Calif. along path of fireball Apr. 26, 2012 06:34 AM Associated Press RENO, Nev. -- Robert Ward has been hunting and collecting meteorites for more than 20 years, so he knew he'd found something special in the Sierra foothills along the path of a flaming fireball that shook parts of Northern California and Nevada with a sonic boom over the weekend. And scientists have confirmed his suspicions: it's one of the more primitive types of space rocks out there, dating to the early formation of the solar system 4 to 5 billion years ago. "It was just, needless to say, a thrilling moment," Ward of Prescott, Ariz., told The Associated Press in a telephone interview Wednesday as he walked through an old cemetery in search of more meteorites about 35 miles northeast of Sacramento. He found the first piece on Tuesday along a road between a baseball field and park on the edge of Lotus near Coloma, where James W. Marshall first discovered gold in California, at Sutter's Mill in 1848. Ward, who has found meteorites in every continent but Antarctica and goes by "AstroBob" on his website, said he "instantly knew" it was a rare meteorite known as "CM" -- carbonaceous chondrite -- based in part on the "fusion crusts from atmospheric entry" on one side of the rock. "It is one of the oldest things known to man and one of the rarest types of meteorites there is," he said. "It contains amino acids and organic compounds that are extremely important to science." Ward actually has two rocks but suspects they were part of the same small meteorite that broke on impact. Each weighs about 10 grams -- about the same as two nickels. He said his only previous finds that rival this one were three lunar meteorites he found years ago in the Middle East. Experts say the flaming meteor was probably about the size of a minivan when it entered the Earth's atmosphere with a loud boom and about one-third of the explosive force of the atomic bomb. It was seen from Sacramento, Calif., to Las Vegas and parts of northern Nevada. An event of that size might happen once a year around the world, said Don Yeomans of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "But most of them occur over the ocean or an uninhabited area, he said. "Getting to see one is something special," he said. He added, "most meteors you see in the night's sky are the size of tiny stones or even grains of sand, and their trail lasts all of a second or two." The meteor probably weighed about 154,300 pounds, said Bill Cooke, a specialist in meteors at NASA's Marshall Space Flight Center in Huntsville, Ala. At the time of disintegration, he said, it probably released energy equivalent to a 5-kiloton explosion -- the Hiroshima bomb was 15 kilotons. "You don't often have kiloton rocks flying over your head," he said. The boom, another expert said, was caused by the speed with which the space rock entered the atmosphere. Meteorites enter Earth's upper atmosphere at somewhere between 22,000 mph and 44,000 mph -- faster than the speed of sound, thus creating a sonic boom. The friction between the rock and the air is so intense that "it doesn't even burn it up, it vaporizes," said Tim Spahr, director of the Minor Planet Center at Harvard University. John T. Wasson, a longtime professor and expert in meteorites at UCLA's Institute of Geophysics and Planetary Physics, said he understood that in addition to Lotus, another small meteorite had been in nearby Coloma, Bits of the meteor could be strewn over an area as long as 10 miles, most likely stretching west from Coloma, he said. "I'm sure more will be found, I'm hoping, including some fairly big pieces," Wasson said. "The fact that two pieces already have been found means one knows where to look." Wasson suspected hundreds of dealers and collectors already have joined the search. He said it was important to recover the meteorites soon because any rain will cause them to degrade, losing their sodium and potassium. "From my viewpoint as a meteorite researcher," he said, "I'm hopeful some big pieces are found right away." Yeomens confirmed this type of meteorite is one of the oldest, dating to the origin of the solar system 4 to 5 billion years ago. And it's "actually kind of unusual," he said. Yeomens said it's got two of the most important chemicals that scientists look for: carbon and a form of water. In fact, this type of space rock is likely full of water and would have made a good candidate for the new space company announced Tuesday that plans to mine asteroids, he said. "And this one landed in their backyard for a lot less than they planned to spend," he said. The mini-van sized asteroid wasn't on NASA's lengthy list of near Earth objects that they track coming close to the planet, so it took scientists by surprise. "There are millions of objects of that size that we don't know about," he said. "They're too small to image unless they're right up on top of you." ------ AP Science Writer Seth Borenstein contributed to this story from Washington, D.C.
Here is one of the articles I read a few days ago about this monster meteorite. Explosion, fireball reported in Nevada, California Apr. 22, 2012 12:28 PM AP RENO, Nev. (AP) -- A loud explosion heard across much of Nevada and California on Sunday morning rattled homes and prompted a flood of calls to law enforcement agencies on both sides of the Sierra Nevada, some reporting fireball sightings. The sound and the light show were likely caused by a meteor that entered Earth's atmosphere, astronomers said. "It made the shades in my room shake hard enough to slam into the window a couple times," said Nicole Carlsen of the Reno area. "I kept looking for earthquake information, but (there was) nothing. I even checked the front of my house to make sure no one ran into the garage. I wish I had seen the meteor." Erin Girard-Hudson of Arnold, Calif., told The Union Democrat of Sonora, Calif., that the loud boom that occurred around 8 a.m. made her 2-year-old daughter, Elsie, cry. "It knocked me off my feet and was shaking the house," she said. "It sounded like it was next door." No damages or injuries were immediately reported. There were no reports of earthquakes at the time. Some people reported seeing a brilliant light streak across the sky at the same time. Sightings occurred over roughly a 600-mile line across the two states, including Reno, Elko and North Las Vegas in Nevada, and the San Francisco, Sacramento and Bakersfield areas in California. Astronomers said they believe the mysterious light was a fireball, which is a very bright meteor. It will take time to determine the path of the fireball and where it broke up, they added. "From the reports, I have no doubt it was a fireball," said Robert Lunsford of the Geneseo, N.Y.-based American Meteor Society. "It happens all the time, but most are in daytime and are missed. This one was extraordinarily bright in the daylight." Lunsford said it's "pretty rare" for fireballs to produce a loud explosion. For that to happen, he explained, the meteor must have survived intact until breaking up about five miles above Earth. Most fireballs are visible at 50 miles above Earth. "If you hear a sonic boom or loud explosion, that's a good indication that some fragments may have reached the ground," Lunsford told The Associated Press. "We'll have to get some people to work on it to pinpoint where it broke up and see if anything can be found on the ground." Lunsford said more than 20 people in the two states had filed reports with his group by midmorning about seeing the fireball. "I have been looking at the sky for 30 years, and I have never witnessed something so amazing and puzzling. It is an event that makes you glad to be alive," said Matthew Neal of San Francisco. "The main body was bright green and the head was bright red and white." Greg Giroux of June Lake, Calif., located along the eastern Sierra just west of Yosemite National Park, also was impressed. "This was by far the brightest fireball/shooting star I've ever seen, especially since it was in full sunlight," he said. "After the flash, it broke up into pieces, then I lost sight of it as it went behind a mountain." In Nevada, the light show was seen as far east as Elko, about 300 miles east of Reno, and as far south as the Las Vegas area. Marcia Standifer of Spring Creek, near Elko, and her husband were out drinking coffee when they saw the fireball at the same time. "It was a very bright ball of white light, then dimmer to the horizon," she said. "We thought this was very unusual due to the bright daylight and how vivid the object was." Tracey Cordaro of North Las Vegas said the sighting "took my breath away." "It was amazing," she said. "It looked as if it was disintegrating rapidly, but was still quite large when it disappeared from my view ... (It was) bright green, visible in the bright sunlight." Dan Ruby, associate director of the Fleischmann Planetarium at the University of Nevada, Reno, said it's unlikely the fireball had anything to do with the current peak of the Lyrid meteor shower. "People are putting two and two together and saying it has something to do with the meteor shower," he said. "But the fireball was probably coincidental and unrelated to the peak of the meteor shower." Though the fireball was seen over such a wide area, Ruby said it was likely just "a little bigger than a washing machine." |