*Interesting 24 hours…*
If the fireball and explosion witnessed by residents along the mid-Atlantic coast Sunday night was a meteor, it’s likely that fragments survived and hit the ocean, an astronomy expert says.
The explosions occurred one to two minutes after the fireball disappeared, which means that a meteor penetrated deep into the atmosphere, said Alan MacRobert, senior editor of Sky and Telescope magazine. That makes it more likely that meteorites survived to hit the ground, although it is not certain.
MacRobert encouraged eyewitnesses to report what they saw at www.amsmeteors.org/fireball/report.html, or at www.spaceweather.com. Scientists can predict where to look for meteorites on the ground “if enough people can accurately reconstruct the flight path that they saw in the sky, or if they can simply say ‘It went behind that tree,’ ” he said.
S. Kent Blackwell, an amateur astronomer, was sky-watching in Pungo when the explosion occurred around 10 p.m. Sunday.
“This brilliant green meteor was probably two or three times brighter than the full moon,” Blackwell said. “Then it turned orange with a white core and disappeared.”
One to two minutes later, a loud low-frequency noise shook houses in Norfolk and Virginia Beach.
“It was a very ominous, low-frequency rumble,” said Robert Hitt, director of the Chesapeake planetarium, who lives in the Acredale section of Virginia Beach. “The sound was quite different from what you hear from thunder.”
Sound is quite rare with fireballs, according to a fact sheet from the American Meteor Society, but there can be two kinds. One is a sonic boom one to two minutes after the visible light, created by fireballs usually brighter than magnitude -8. In comparison, the meteor society says the North Star is magnitude 2.1 and a bright Venus is -4.4. The full moon is -12.6 and the sun is -26.7.
The other kind of sound that can accompany fireballs is called electrophonic. It occurs at the same time as the flash is seen and may sound like a hiss, a sizzle or popping noise.
“Often, the witness of such sounds is located near some metal object when the fireball occurs,” according to the meteor society fact sheet. “Additionally, those with a large amount of hair seem to have a better chance of hearing these sounds.”
These sounds may be radio waves, but they have not been scientifically identified, it says.
Many Hampton Roads residents heard a boom, even though they were inside and did not see the flash. One viewer, in an online comment to the newspaper, reported thinking a tree had hit the house. Another said window blinds rattled with the boom.
Most reports place the fireball and noise at around 9:50 p.m., but one local viewer reported seeing a brilliant flash of light at 2:30 a.m. while traveling between Elizabeth City and Virginia Beach.
No meteor showers are taking place at the moment. The next one is predicted for April 21-22.
The Virginia Beach 911 center had numerous calls waiting just before 10 p.m., a supervisor said.
The National Weather Service said reports were made from Dorchester County, Md., to the Virginia/North Carolina border.
Chris Wamsley, a meteorologist with the National Weather Service’s Wakefield office, said a team is looking into what happened.
Lindsey Hosek of the Great Neck area of Virginia Beach was jogging along the water with her dog when the sky lit up, she said.
“The bright light at first terrified me because I thought somebody was shining a light on me, and then I saw it, and I was in complete awe because it was so beautiful,” she said.
Then she saw something that looked like a comet moving low toward the ground; it was blue in front followed by orange and appeared to be the shape and size of a refrigerator.
“It was just so low. It was like where a bird should be,” she said. “It was definitely heading downward.”
In an e-mail to The Pilot, a reader reported seeing something similar at 2:30 a.m. “The sky turned brilliant blue,” wrote Bobby Smith. “I’ve never seen anything like it. Here’s the catch: I saw it at approximately 2:30 a.m. on Sunday morning on Route 17 coming to Virginia Beach from Elizabeth City.”
The American Meteor Society seeks as much information as possible about brightness, length across the sky, color, how long it lasted, direction of travel and position in the sky as compared to constellations or even trees and buildings. Although the sight was unusual, the American Meteor Society reports that thousands of fireballs occur in Earth’s atmosphere each day, many during daylight when they cannot be easily seen, others in remote locations.
Blackwell said the meteor was moving north-northeast between the constellations Ursa Minor and Ursa Major. “I’ve been observing more than 40 years but have never seen a meteor this bright,” he said. “It was absolutely spectacular!”
Mark Ost of Pungo, who was observing with Blackwell, posted this report on spaceweather.com:
“The fireball was approximately 36 to 40 degrees above the horizon … Assuming the speed of sound at 600 mph, I calculated the distance to be 20 to 30 miles away.”
Blackwell suspects that meteorites, if there were any, fell into the ocean, which would be disappointing.
“Heck, I wish it had landed in my driveway!” he said.
http://hamptonroads.com/2009/03/loud-explosions-lights-sky-reported-maryland-nc
