A meteor entering the Earth’s atmosphere exploded in Michigan’s sky overnight in a spectacle that briefly illuminated the city of Detroit. The US Geological Survey confirmed the meteor had entered the atmosphere about 5 miles from New Haven, Michigan (about 36 miles north of The Motor City), and registered a force equivalent to a magnitude 2.0 earthquake. Videos posted across social media networks showed a bright spot streaking across the sky before exploding, flooding the darkness with light. Social media users who witnessed the event said the flash of light was followed by loud booms several minutes later.
NASA officials confirmed to The Detroit News that its meteor camera caught the event at 8:08pm at Oberlin College in Ohio (see below). NASA is currently analyzing the meteor’s data, and said the explosion was a “huge event” and rare for Michigan. Bill Cooke from NASA’s meteoroid environment office in Alabama told The Detroit News he estimates the meteor was about one or two yards across, weighed more than one metric ton and traveled between 40,000 to 50,000 miles to get to Earth.
NASA defines meteors (or shooting stars) as rocks or debris in space that fall through a planet’s atmosphere. The bright trail of light emitted is caused by friction with the atmosphere. Meteorites are the surviving pieces that make it to the ground. NASA says it’s tracking the trajectory of the meteor to see if any meteorites landed on Earth.
Quelle: The Verge
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NASA officials confirmed its meteor camera spotted the material at about 8:08 p.m. at Oberlin College in Ohio. The image shows a tiny white ball traversing the screen until a bright flash is seen when it appears to make impact. NASA
The flashing light and loud boom felt across Michigan and seen as far away as New York City and parts of Canada on Tuesday night was a meteoroid entering the atmosphere, according to NASA.
NASA officials confirmed its meteor camera spotted the event at about 8:08 p.m. at Oberlin College in Ohio. The image shows a tiny white ball traversing the screen until a bright flash is seen when it appears to make impact.
Around the same time, the U.S. Geological Survey reported a “M 2.0 Meteorite,” referring to magnitude, about 5 miles west of New Haven.
The nighttime spectacle was a “huge event” astronomically speaking, and rare sight for Michigan, said Bill Cooke with NASA’s meteoroid environment office in Alabama. “It is definitely a meteoroid.”
The nighttime display quickly set social media aflutter with posts about UFOs and explosions as locals and experts alike marveled over the cinematic scope.
It was an unusual sight for Mike Tarkowski, who was sitting at home in Milford watching TV on Tuesday when what had been a typical night suddenly became anything but.
At about 8:10 p.m., he spotted “an extremely bright light” illuminating his otherwise dark room.
“All of the sudden, the whole yard started getting brighter, kind of yellowish-orange, like a flashbulb, then got black ... ,” he said. “It was something big and it was something up in the air.”
NASA defines “shooting stars” or meteors as bits of interplanetary material falling through Earth’s atmosphere and heated to incandescence by friction. They’re called meteoroids while hurtling through space, then become meteors for the few seconds they streak across the sky and create glowing trails, according to the agency.
The earth periodically encounters a few small asteroids or large meteoroids, Cooke said, “and when they hit the atmosphere, they create these very bright fireballs.”
NASA is studying the trajectory and analyzing data, but Cooke estimates the meteoroid Tuesday appears to have been about one or two yards across, weighed more than a metric ton and traveled 40,000 to 50,000 miles to Earth.
“Over Michigan, they’re rare,” he said. But elsewhere on the planet, “they happen a few times every month.”
Meteoroids may be common, but the associated fireballs, or bolides, “are extremely rare,” said Bob Trembley, a former outreach officer for the Warren Astronomical Society and volunteer NASA/JPL solar system ambassador who has long studied the phenomenon. “Anybody that saw it is lucky,” he said.
Plenty did, judging by Twitter and the National Weather Service, which said it received reports from around Metro Detroit of “a flash and a boom.”
“Somebody was reporting lightning with thunder,” said meteorologist Cory Behnke. “We checked our observational data here, and I can tell you we’ve not had any lightning.”
Sightings or those hearing the boom were reported on Twitter from Michigan and beyond.
“Just saw a meteor streak across the sky just now,” one Twitter user tweeted. “It was followed by loud booms about 3 minutes later. Bright blue and orange fire. So glad I saw it!!”
Another wrote: “Think a meteor whizzed by in Brighton, Michigan. Saw a blue light and heard a rumble. Sky is clear no snow.”
The Ingham County Office of Homeland Security & Emergency Management, which fielded multiple 911 calls about the event, tweeted: “All indications are that it was just a natural meteor fireball.”
Danny McEwen Jr. was driving on Fish Lake Road in Holly when he noticed a bright streak of light behind him and then saw the fireball.
“I went to turn and I noticed a ball of flame coming at an angle,” he said. “It just blew up into a bunch of sparks. I didn’t even know what to think. It was kind of odd how orange the sky was behind me and this blaze of flame out of nowhere.”
The incident was so widespread that McEwen’s father said the orange hue lit up his living room and friends working in Brighton told him they saw the streak overhead. In Oak Park, another acquaintance reported hearing a boom she thought was her son having knocked his TV off his dresser.
Shortly after the event, DTE Energy customers called the utility to report they heard loud booms and saw flashing light, spokesman Brian Smith said.
The sound came from the meteor entering the atmosphere, Cooke said.
Meanwhile, the appearance apparently generated such interest, the website for the American Meteor Society and the International Meteor Organization temporarily shut down.
“Major event in Michigan. Server is getting overloaded. We’ll be back asap, check back soon,” read a message on the site, which directed visitors to report fireball sightings online.
NASA officials will track the meteoroid’s orbit and learn if any meteorites landed, Cooke said.
Those fragments typically leave an oval pattern on the ground that scientists and enthusiasts are likely to search for, Trembley said. “I’m pretty sure there are going to be hunters out there looking for it.”
Quelle: The Detroit News
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Update: 18.01.2018
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Meteorit dringt in Erdatmosphäre ein – Lichtblitz versetzt Menschen in Angst
Michigan. Ein gleißender Blitz war am Himmel zu sehen – gefolgt von einem lauten Donner. Das Naturschauspiel versetzte zahlreiche Menschen in den USA und Kanada am Dienstagabend in Angst und Schrecken. Sie teilten Bilder von dem ungewöhnlichen Spektakel in den sozialen Netzwerken. Wie die Nasa bestätigte, wurde der Blitz von einem Meteoriten verursacht, der in die Erdatmosphäre eingedrungen war.
„Es war definitiv ein Meteorit“, erklärte Bill Cooke, ein Mitarbeiter der Nasa, erklärte gegenüber der „Washington Post“. Etwa einmal im Monat würden Meteoriten oder andere Festkörper ähnlicher Größe in die Atmosphäre der Erde eindringen. Da sie normalerweise jedoch nicht derart helle Blitze verursachen, bekämen Menschen das meist nicht mit, so Cooke weiter.
Phänomen für Michigan „sehr selten“
Der Meteorit sei über dem US-Bundesstaat Michigan abgestürzt. Für diese Region sei das Phänomen „sehr selten“. Das Lichtschauspiel sei entstanden, als der Meteorit nach seinem Eintritt in die Atmosphäre zu schmelzen begann und dadurch hell erstrahlte, erklärte Cooke.
Die Nasa bereitete mit ihrer Bestätigung den wilden Spekulationen in sozialen Medien ein Ende, es könne sich bei der Erscheinung um Ufos oder Explosionen gehandelt haben.
Quelle: DERWESTEN
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What you need to know about the meteor that caused seismic shock over Michigan
The meteor that lit up the night sky over southeast Michigan and shook the ground Tuesday night did not actually cause an earthquake, researchers say.
In fact, meteors do not cause earthquakes to rupture along a fault, according to William Yeck, a research geophysicist at the United States Geological Survey's National Earthquake Information Center in Golden, Colorado.
The seismic observations associated with the meteor were assigned a magnitude 2.0 by the United States Geological Survey, which said the event was centered about 5 miles west-southwest of New Haven, Michigan, some 40 miles northeast of Detroit. The National Weather Service sent out a tweet that said, "USGS confirms meteor occurred around 810 pm, causing a magnitude 2.0 earthquake."
But Yeck said the magnitude cannot be directly used to compare the meteor's size to an earthquake because the source of the seismic signals are different.
"While the event was reported as a magnitude 2, the magnitude scale is used to estimate the size of earthquakes and therefore is not an accurate representation of the observations from a meteor," Yeck told ABC News.
Researchers are still investigating this specific incident, Yeck said. The seismic waves observed from these events are typically not from an impact but instead are sound waves generated in the atmosphere.
Bill Cooke, the lead of NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama, said Tuesday night's phenomenon occurred when a meteor, measuring about 2 yards in diameter and traveling at about 28,000 mph, entered the Earth's atmosphere over Michigan.
The pressure difference between the air in front of the meteor and the air behind it caused the rock to break apart and explode in the sky with the force of less than 100 tonnes of TNT, Cooke said. That explosion generated shock waves that traveled down to the ground northeast of Detroit, where residents heard a loud boom and felt the ground beneath them tremble.
The meteor would not have landed intact, Cooke said, but rather tiny pieces weighing only a few ounces would have scattered over the area.
And it's not a rare event.
"It's common with fireballs that produce meteorites on the ground," Cooke said. "When the shock waves hit the ground, it will shake the ground a bit."
Still, the explosive flash, the sonic boom and the ensuing vibrations on the ground both dazzled and startled residents.
"That's probably a little bit disconcerting," Cooke said.
Although meteorites have damaged cars and the roofs of homes, Cooke said no one has been killed by a meteorite in recorded history.
"I would say most folks are pretty safe," he said.
Quelle: abcNews
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Update: 20.01.2018
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Hunters Recover Meteorites From Michigan Fireball
A spectacular fireball seen by hundreds of people from Iowa to Ontario delivered precious samples from the asteroid belt to the lake country of southern Michigan Tuesday night.
A beautiful, fusion-crusted meteorite fragment from the Michigan fall finds itself on the snowy Earth after traveling millions of miles.
Mike Hankey / American Meteor Society
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On January 16th around 8:10 p.m. EST, a brilliant, green fireball crackled across southern Michigan skies. Eyewitnesses described it as brighter than the full Moon with sparks and an orange tail. At least 77 observers reported hearing explosive sounds as the meteoroid broke apart overhead.
The American Meteor Society(AMS), a clearinghouse for meteor sightings, has received 657 reports of the fireball with some as far away as Iowa and southern Ontario.
The fireball traveled relatively slowly at around 45,000 km (28,000 miles) per hour. That sounds fast, but it's more than 4½ times slower than a typical summertime Perseid. Its slow speed and great brilliance suggests a fairly large space rock that penetrated deep into the atmosphere, according to Mike Hankey of the AMS.
Professional meteorite hunter Robert Ward holds one of the first-discovered meteorites from the Michigan fireball that blazed across the sky on January 16th. Ward and at least one other person have recovered several rocks from the fall. The black crust is a thin skin of rock that melted as the meteoroid was heated by the atmosphere during its fall.
American Meteor Society (AMS)
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While fireballs are relatively common, ones that drop meteorites are rare, and it's rarer still for someone to find those black treasures. But by using Doppler weather radar data and seismic traces (more on that in a moment), meteorite hunters were able to pinpoint the strewn field, the name for the ground footprint where the space rocks might have fallen. Lately of the asteroid belt, these interplanetary fragments now call the Township of Hamburg, Michigan, home.
The figures represent folks who spotted the fireball Tuesday night.
Google / AMS
The strewn field extends about 5 miles, oriented east-southeast to west-northwest, from about Highway 23 up to Bass Lake, some 20 miles northwest of Ann Arbor. Since the area has many lakes, make sure the ice is sound before venturing out.
Anyone living in that area should be on the lookout for black rocks poking out of the snow similar to what Ward is holding in the photograph above. The black coating, called fusion crust, forms when the outside of the meteoroid is heated and melted by friction from the air during its flight through the atmosphere. Fusion crust is typically only 1-2 mm thick.
This is a trace of the pressure wave recorded at Ann Arbor.
Rob Matson
The Michigan fireball not only put on a light show, it "knocked down the door," announcing its arrival with a 2.0-magnitude seismic event recorded by the U.S. Geological Survey. The blast was not from the impact itself but from the air pressure wave created during the explosive breakup of the meteoroid in the atmosphere.
A preliminary analysis indicates it's possibly an L6 chondrite, a common stony meteorite type. The "L" stands for low iron and "6" (on a scale from 3 to 7, from least to most altered by heat) indicates that the meteorite was strongly heated, so it likely originated from a larger asteroid. Samples are on their way now to the Chicago Field Museum for more detailed analysis.
Quelle: Sky&Telescope