Space Force is Releasing Decades of Tracking Data on a Thousand Bright Meteor Fireballs

Bright Fireball Credit: Adrian West

When a meteoroid enters the Earth’s atmosphere at a very high speed it heats up. This heating up produces a streak of light and is termed a meteor. When a meteor is bright enough, about the brightness of Venus or brighter, it becomes a fireball. Sometimes these fireballs explode in the atmosphere, becoming bolides. These bolides are bright enough to be seen even during the day.

Studying bolides as they pass through the atmosphere can help model larger asteroids, something of interest to the Planetary Defense Coordination Office (PDCO) which is run by NASA. These asteroids can be deadly if they are large enough, and learning how to predict their behavior is essential to protecting our planet from a devastating impact with long-term implications for the survival of many species on Earth.

Continue reading “Space Force is Releasing Decades of Tracking Data on a Thousand Bright Meteor Fireballs”

Satellites Watched a Huge Fireball Explode Above the Bering Sea Late Last Year

NASA's MODIS instrument, aboard the Terra satellite, captured this true-color image showing the remnants of a meteor's passage, seen as a dark shadow cast on thick, white clouds on Dec. 18, 2018. Credit: NASA GSFC

When a meteor strike the Earth’s atmosphere, a magnificent (and potentially deadly) explosion is often the result. The term for this is “fireball” (or bolide), which is used to describe exceptionally bright meteor explosions that are bright enough to be seen over a very wide area. A well-known example of this is the Chelyabinsk meteor, a superbolide that exploded in the skies over a small Russian town in February of 2013.

On December 18th, 2018, another fireball appeared in the skies over Russia that exploded at an altitude of about 26 km (16 mi) above the Bering Sea. The resulting debris was observed by instruments aboard the NASA Terra Earth Observation System (EOS) satellite, which captured images of the remnants of the large meteor a few minutes after it exploded.

Continue reading “Satellites Watched a Huge Fireball Explode Above the Bering Sea Late Last Year”

Super Bright Fireball Spotted Across U.S. Northeast

Bright meteor captured on a webcam in Portsmouth, New Hampshire on May 17, 2016. Via www.portsmouthwebcam.com

It came from outer space—literally! On Tuesday, May 17, 2016, the early morning sky briefly lit up with the brilliant flash of a fireball—that is, an extremely bright meteor—over much of eastern New England states and even parts of southeastern Canada.

The event, which occurred around 12:50 a.m. EDT (04:50 UTC), was reported by witnesses from Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, Ontario, and Québec, and captured on several automated cameras like a webcam in Portsmouth, NH (seen above) and a police dashcam in Plattsburgh, NY (below).

The fireball appeared to be moving from southwest to northeast and for some witnesses created an audible sonic boom, heard (and felt) several minutes later.

See more videos of this event from local news stations WMTW and WGME (Maine) and WMUR (New Hampshire) and from the Ogunquit police department on Twitter.

Meteors are the result of debris in space rapidly entering Earth’s upper atmosphere, compressing the air and causing it to quickly release energy in the form of heat and optical light. If the entering object is massive enough it may violently disintegrate during its fall, creating both light and sound. This particular meteor technically classifies as a bolide, due to its brightness, eruption, and visible fragmentation. Learn more about the various types of meteors here.

No reports of a meteorite impact at ground level have been made although I must assume there will be individuals who go on the hunt—meteorite fragments, especially those associated with witnessed events, can be quite valuable.

Full-frame image of the May 17, 2016 fireball from Portsmouth, NH (www.portsmouthwebcam.com)
Full-frame image of the May 17, 2016 meteor from Portsmouth, NH (portsmouthwebcam.com)

Did you witness the event or capture it on camera? Report your sighting of this or any other fireballs on the AMS site and be sure to send your fireball videos or images to the American Meteor Society here.

Source: American Meteor Society

Added May 18: here’s a beautiful video of the same bolide captured from Saint-Jacques-le-Mineur, Québec by Dany Bilodeau (ht to Massimo on Twitter)

Kick Back, Look Up, We’re In For a GREAT Perseid Meteor Shower

Multi-photo composite showing Perseid meteors shooting from their radiant point in the constellation Perseus. Earth crosses the orbit of comet 109P/Swift-Tuttle every year in mid-August. Debris left behind by the comet burns up as meteors when it strikes our upper atmosphere at 130,000 mph. Credit: NASA

Every year in mid-August, Earth plows headlong into the debris left behind by Comet 109P/Swift-Tuttle. Slamming into our atmosphere at 130,000 mph, the crumbles flash to light as the Perseid meteor shower. One of the world’s most beloved cosmic spectacles, this year’s show promises to be a real crowd pleaser.

The author tries his best to enjoys this year's moon-drenched Perseids from the "astro recliner". Credit: Bob King
The author takes in last year’s moon-drenched Perseids from a recliner. Credit: Bob King

Not only will the Moon be absent, but the shower maximum happens around 3 a.m. CDT (8 UT) August 13 — early morning hours across North America when the Perseid radiant is highest. How many meteors will you see? Somewhere in the neighborhood of 50-100 meteors per hour. As always, the darker and less light polluted your observing site, the more zips and zaps you’ll see.

Find a place where there’s as few stray lights as possible, the better to allow your eyes to dark-adapt. Comfort is also key. Meteor showers are best enjoyed in a reclining position with as little neck craning as possible. Lie back on a folding lawn chair with your favorite pillow and bring a blanket to stay warm. August nights can bring chill and dew; a light coat and hat will make your that much more comfortable especially if you’re out for an hour or more.

The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the name "Perseids". Source: Stellarium
The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the shower’s name. This map shows the sky facing northeast around 12:30 a.m. local time August 13. Source: Stellarium

I’m always asked what’s the best direction to face. Shower meteors will show up in every corner of the sky, but can all be traced backwards to a point in Perseus called the radiant. That’s the direction from which they all appear to stream out of like bats flying out of a cave.

Another way to picture the radiant it is to imagine driving through a snowstorm at night. As you accelerate, you’ll notice that the flakes appear to radiate from a point directly in front of you, while the snow off to the sides streams away in long trails. If you’re driving at a moderate rate of speed, the snow flies past on nearly parallel paths that appear to focus in the distance the same way parallel railroad tracks converge.

At some personal peril, I grabbed a photo of snow in the headlights while driving home in a recent storm. Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion. Photo: Bob King
Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion to driving a car in a snowstorm. The motion of the car (Earth) creates the illusion of  meteors radiating from a point in the sky ahead of the observer. Credit: Bob King

Now replace your car with the moving Earth and comet debris for snow and you’ve got a radiant and a meteor shower. With two caveats. We’re traveling at 18 1/2 miles per second and our “windshield”, the atmosphere, is more porous. Snow bounces off a car windshield, but when a bit of cosmic debris strikes the atmosphere, it vaporizes in a flash. We often think friction causes the glow of meteors, but they’re heated more by ram pressure.

A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack
A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack

The incoming bit of ice or rock rapidly compresses and heats the air in front of it, which causes the particle to vaporize around 3,000°F (1,650°C). The meteor or bright streak we see is really a hollow “tube” of glowing or ionized air molecules created by the tiny rock as its energy of motion is transferred to the surrounding air molecules. Just as quickly, the molecules return to their rest state and release that energy as a spear of light we call a meteor.

Imagine. All it takes is something the size of a grain of sand to make us look up and yell “Wow!”

Speaking of size, most meteor shower particles range in size from a small pebble to beach sand and generally weigh less than 1-2 grams or about what a paperclip weighs. Larger chunks light up as fireballs that shine as bright as Venus or better. Because of their swiftness, Perseids are generally white and often leave chalk-like trails called trains in their wakes.

Comet 109P/Swift-Tuttle captured during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity on Aug. 12 around 18:39 UT. Credit: Gerald Rhemann
Comet 109P/Swift-Tuttle seen during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity around 18:39 UT on August 12. Credit: Gerald Rhemann

This year’s shower is special in another way. According to Sky and Telescope magazine, meteor stream modeler Jeremie Vaubaillon predicts a bump in the number of Perseids around 1:39 p.m. (18:39 UT) as Earth encounters a debris trail shed by the Comet Swift-Tuttle back in 1862. The time favors observers in Asia where the sky will be dark. It should be interesting to see if the prediction holds.

How To Watch

Already the shower’s active. Go out any night through about the 15th and you’ll see at least at least a handful of Perseids an hour. At nightfall on the peak night of August 12-13, you may see only 20-30 meteors an hour because the radiant is still low in the sky. But these early hours give us the opportunity to catch an earthgrazer — a long, very slow-moving meteor that skims the atmosphere at a shallow angle, crossing half the sky or more before finally fading out.

I’ve only seen one good earthgrazer in my earthly tenure, but I’ll never forget the sight. Ambling from low in the northeastern sky all the way past the southern meridian, it remained visible long enough to catch it in my telescope AND set up a camera and capture at least part of its trail!

A Perseid meteor streaks across the northeastern sky two Augusts ago. This year's shower will peak on the night of August 12-13 with up to 100 meteors per hour visible from a dark sky. Credit: Bob King
A Perseid meteor streaks across the northeastern sky two Augusts ago. Give the shower an hour’s worth of your time – you won’t be disappointed. Credit: Bob King

The later you stay up, the higher the radiant rises and the more meteors  you’ll see. Peak activity of 50-100 meteors per hour will occur between about 2-4 a.m. No need to stare at the radiant to see meteors. You can look directly up at the darkest part of the sky or face east or southeast and look halfway up if you like. You’re going to see meteors everywhere. Some will arrive as singles, others in short burst of 2, 3, 4 or more. I like to face southeast with the radiant off to one side. That way I can see a mix of short-trailed meteors from near the radiant and longer, graceful streaks further away just like the snow photo shows.

If there’s a lull in activity, don’t think it’s over. Meteor showers have strange rhythms of their own. Five minutes of nothing can be followed by multiple hits or even a fireball. Get into the feel of the shower as you sense spaceship Earth speeding through the comet’s dusty orbit. Embrace the chill of the August night under the starry vacuum.

Flaming Space Junk Makes Jaws Drop in Australia

Frame grab from a Youtube video of the brilliant meteor that flared over Australia overnight.

“It first looked like a plane with fire coming out of the tail.” — Aaron O.

“I have never seen anything like it. Big, bright and moving gently across sky – slower than a plane, not falling at all but moving across.” — Shannon H.

“Viewed from cockpit of aircraft at 37,000′. Was visible for two or three minutes.” — Landy T.

Flaming plane? Incandescent visitor from the asteroid belt? As the these comments from the AMS Fireball Log attest, the brilliant and s-l-o-w fireball that seared the sky over  southeastern Australia tonight was probably one of the most spectacular displays of re-entering space junk witnessed in recent years.

Ted Molczan, citizen satellite tracker and frequent contributor to the amateur satellite watchers SeeSat-L sitenotes that the timing and appearance almost certainly point to the decay or de-orbiting of the Russian Soyuz 2-1B rocket booster that launched the meteorological satellite Meteor M2 on July 8.


Meteor over New South Wales. Look closely near the end and you’ll see it disintegrate into small pieces.

The magnificent man-made meteor, weighing some 4,400 pounds (2,000 kg), was seen from Melbourne to Sydney across the states of Victoria and New South Wales around 10 p.m. Hundreds of people were stopped in their tracks.  Most noticed how slowly the fireball traveled and how long it continue to burn on the way down.

Spacecraft that reenter from either orbital decay or controlled entry usually break up at altitudes between 45-52 miles (84-72 km) traveling around 17,500 mph (28,000 km/hour) . Compression and friction from the ever-thickening air cause the craft, or in this case, the rocket booster, to slow down and heat up to flaming incandescence just like a hunk of space rock arriving from the asteroid belt. In both cases, we see a brilliant meteor, however manmade debris.

Jan 21, 2001, a Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East. The titanium motor casing, weighing about 70 kg, landed in Saudi Arabia about 240 km from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office
A Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East on Jan. 21, 2001. The titanium motor casing, weighing about 154 lbs. (70 kg), landed in Saudi Arabia about 150 miles from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office

Occasional meteoroids break apart in the atmosphere and scatter meteorites just as pieces of occasional satellites, especially large, heavy craft, can survive the plunge and land intact –  if a tad toasted.  Whether anything remains of Russian rocket stage or where exactly it fell is still unknown. Here are a few more photos of successful space junk arrivals.

The only person to be hit by manmade space debris was Lottie Williams in 1997.  She was unharmed. Credit: Tulsa World
The only person to be hit by manmade space debris was Lottie Williams in 1997. She was unharmed. Credit: Tulsa World

Reportedly, only one person has been struck by satellite debris. In 1997 Lottie Williams of Tulsa, Oklahoma was hit on the shoulder while walking by a small, twisted piece of metal weighing as much as a crushed soda can. It was traced back to the tank of a Delta II rocket that launched a satellite in 1996. I suppose it’s only a matter of time before someone else gets hit, but the odds aren’t great. More likely, you’ll see what alarmed and delighted so many southeastern Australians Thursday night: a grand show of disintegration.

Eureka! Kola Fireball Meteorites Found in Russia

Amateur astronomer and physics teacher Asko Aikkila managed to catch the Kola fireball on videotape in Kuusamo, Finland on April 19, 2014. The picture has been processed to enhance the details. Credit: Asko Aikkila / Finnish Fireball Network

A spectacular fireball that crackled across the sky near the Russia-Finnish border on April 19th this year left more than a bright flash. A team of meteor researchers from Finland, Russia and the Czech Republic scoured the predicted impact zone and recently discovered extraterrestrial booty.

A 120 gram fragment of the Annama meteorite. Streamlines of molten material heated during atmospheric entry can be seen on the crust. Credit: Jakub Haloda
A 120 gram fragment (left) of the Annama meteorite found on May 29, 2014. Streamlines of molten material heated during atmospheric entry can be seen on the crust. At right, a 48g fragment found on the following day. Credit: Jakub Haloda (left) and Grigory Yakovlev

There’s a lot of excitement about the fall because it’s the first time a meteorite was found based on coordinated all-sky camera network observations by the Ursa Finnish Fireball Network.  Esko Lyytinen of the network with help from Jarmo Moilanen and Steinar Midtskogen reconstructed the meteoroid’s trajectory and dark flight (when it’s no longer luminous but yet to strike the ground) using simulations based on photos, videos and eyewitness reports. 

Kola fireball meteors ended up near the Russian-Norwegian border. The fireball trajectory Esko Lyytinen of Ursa modeling of Heaven, watch videos on the findings and Murmansk.
Kola fireball meteors fell near the Russian-Norwegian border. The
fireball trajectory was modeled  byEsko Lyytinen of the Ursa Finnish Fireball Network. Credit: Kuva Mikko Suominen / Celestia with info boxes translated by the author

The initial mass of meteoroid is estimated at about 1,100 pounds (500 kg). Much of that broke apart in the atmosphere and fell harmlessly as smaller stones. An international team of scientists mounted a 5-day expedition in late May after snow melt and before green up to uncover potential space rocks in the strewnfield, the name given to the oval-shaped zone where surviving fragments pepper the ground. 

Russian amateur astronomer Nikolai Kruglikov discovered the first fragment of Annama meteorite on May 29, 2014 in the middle of a dirt road. Credit: Tomas Kohout
Russian amateur astronomer Nikolai Kruglikov discovered the first meteorite fragment in the middle of a dirt road. Credit: Tomas Kohout

On May 29, 2014, first 120 gram (4.2 ounce) meteorite fragment was found by Nikolai Kruglikov of Russia’s Ural Federal University on a forest road within the predicted impact area. The crew had been searching 1o hours a day when Kruglikov stopped the car to check out a suspect rock:

 “Suddenly he started dancing and yelling. At first I could hardly believe it was a true discovery, but then I checked the composition of the rock using my instrument”, said Tomas Kohout, University of Helsinki physicist who participated in the hunt. The fusion-crusted stone displayed classic flow features from melting rock during high-speed atmospheric entry.

The very next day a second 48 gram crusted meteorite popped up. More are undoubtedly out there but the heavy brush numerous lakes make the finding challenging. 

The crew is calling the new arrival the ‘Annama meteorite’ as it fell near the Annama River in Russia about 62 miles west of Murmansk.  The Czech Geological Survey examined the space rocks and determined them to be ordinary chondrites representing the outer crust of an asteroid that got busted to bits in a long-ago collision. More than 95% of stony meteorites fall into this category including the 2013 fireball of Chelyabinsk, Russia. 

 


Dashcam video of the brilliant fireball that dropped the ‘Annama meteorites’

“The Kola fireball is a rarity – it is one of only 22 cases where it was possible to determine its pre-impact solar system orbit before the impact with Earth’s atmosphere,” says Maria Gritsevich of the Finnish Geodetic Institute. “Knowing where the meteorite originates will help us better understand the formation and evolution of the solar system.” Congratulations Ursa!

Happy 1st Anniversary Chelyabinsk! The Fireball that Woke Up the World

Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn. A study of the area near this meteor air burst revealed similar signatures to the Tall el_Hammam site.
Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn. A study of the area near this meteor air burst revealed similar signatures to the Tall el_Hammam site.

Wonder and terror. Every time I watch the dashcam videos of the Chelyabinsk fireball it sends chills down my spine. One year ago today, February 15, 2013, the good citizens of Chelyabinsk, Russia and surrounding towns collectively experienced these two powerful emotions as they witnessed the largest meteorite fall in over 100 years. 


Incredible compilation of dashcam and security camera videos of the fireball

The Chelyabinsk fall, the largest witnessed meteorite fall since the Tunguska event in 1908, exploded with 20-30 times the force of the atomic bomb over Hiroshima at an altitude of just 14.5 miles (23 km). Before it detonated into thousands of mostly gravel-sized meteorites and dust,  it’s estimate the incoming meteoroid was some 66 feet (20-meters) end to end, as tall as a five-story building. The shock wave from the explosion shattered windows up and down the city, injuring nearly 1,500 people.

Friction and enormous pressures placed upon the Chelyabinsk meteoroid by the atmosphere caused it to explode to pieces and send a shock wave across the cities below. This is a selection of typical small, fusion-crust covered Chelyabinsk meteorites. The U.S. penny is 9mm in diameter. Credit: Bob King
Atmospheric friction pressure on the Chelyabinsk meteoroid caused it to explode to pieces and send a shock wave across the land below. Pictured is a selection of typical small, fusion-crust covered Chelyabinsk meteorites recovered shortly after the fall. The U.S. penny is 9mm in diameter. Credit: Bob King

For nearby observers it briefly appeared brighter than the sun.  NASA Meteorite researcher Peter Jenniskens conducted an Internet survey of eyewitnesses and found that eye pain and temporary blindness were the most common complaints from those who looked directly at the fireball.  20 people also reported sunburns including one person burned so badly that his skin peeled:

Trajectory projection and strewnfield map showing the main fireball (and two additional explosions) at top and the elliptical shaped area where the densest concentration of meteorites were found. Credit: Svend  Buhl and K. Wimmer
Map showing the trajectory of the main fireball in yellow (and two additional explosions at top left). The pink oval, called the strewnfield, is where the densest concentration of meteorites were found. Click to see additional maps. Credit: Svend Buhl and K. Wimmer

“We calculated how much UV light came down and we think it’s possible,” Jenniskens said. Perhaps surprisingly, most of the meteoroid’s mass – an estimated 76% – burned up and was converted to dust during atmospheric entry. It’s estimated that only 0.05% of the original meteoroid or 9,000 to 13,000 pounds of meteorites fell to the ground.


No video I’ve seen better captures the both the explosion of the fireball and ensuring confusion and chaos better than this one.

The largest fragment, weighing 1,442 lbs. (654 kg), punched a hole in the ice of Lake Chebarkul. Divers raised it from the bottom muck on Oct. 16 last year and rafted it ashore, where scientists and excited onlookers watched as the massive space rock was hoisted onto a scale and promptly broke into three pieces. Moments later the scale itself broke from the weight.

The 26-foot-wide (8-meter) hole punched in the ice of Chebarkul Lake by the largest fragment of the Chelyabinsk meteorite. Credit: Eduard Kalinin
The 26-foot-wide (8-meter) hole punched in the ice of Chebarkul Lake by the largest fragment of the Chelyabinsk meteorite. Credit: Eduard Kalinin

There were plenty of meteorite to go around as local residents tracked down thousands of fragments by looking for holes pierced in the snow cover by the hail of space rocks. Working with hands and trowels, they dug out mostly small, rounded rocks covered in fresh black fusion crust, a 1-2 mm thick layer of rock blackened and melted rock from frictional heating by the atmosphere. According to the Meteoritical Bulletin Database entry,  the total mass of the recovered meteorites to date comes to 1,000 kg (2,204 lbs.) with locals finding up to more than half of that total.


Animation of the orbit Chelyabinsk meteoroid via Ferrin and Zuluaga. Meteoroid is the name given a meteor while still orbiting the sun before it enters Earth’s atmosphere.

Thanks to the unprecedented number of observations of the fireball recorded by dashcams, security cameras and eyewitness accounts, astronomers were able to determine an orbit for  Although some uncertainties remain, the object is (was) a member of the Apollo family of asteroids, named for 1862 Apollo, discovered in 1932. Apollos cross Earth’s orbit on a routine basis when they’re nearest the sun. Chelyabink’s most recent crossing was of course its last.

Chelyabinsk meteorites exhibit many signs of  shock created during an asteroid impact long ago. Many specimens show a typical pale white color with small chondrules typical of LL5 chondrite. A closer look shows fine, dark shock veins of melted glass. Other fragments are made of impact melt, rock shocked-heated and blackened by impact. Credit: Bob King
Chelyabinsk meteorites tell the tale of an earlier impact with another asteroid 4.452 billion years ago. Many specimens are pale white with small chondrules typical of LL5 chondrites. A closer look shows fine, dark shock veins of melted glass. Other fragments are made of pure impact melt, rock shocked-heated, melted and blackened by impact. Credit: Bob King

Chelyabinsk belongs to a class of meteorites called ordinary chondrites, a broad category that includes most stony meteorite types. The chondrites formed from dust and metals whirling about the newborn sun some 4.5 billion years ago; they later served as the building blocks for the planets, asteroids and comets that populate our solar system. Chondrites are further subdivided into many categories. Chelyabinsk belongs to the scarce LL5 class — a low iron, low metal stony meteorite composed of silicate materials like olivine and plagioclase along with small amounts of iron-nickel metal.

 

Most of the Chelyabinsk meteorites were shattered and broken during the explosion / shock blast, revealing brecciation, metal and shock veins in their interiors. Credit: Bob King
Most of the Chelyabinsk meteorites were shattered and broken during the explosion / shock blast, revealing brecciation, metal and shock veins in their interiors. Credit: Bob King

A thin slice of Chelyabinsk impact melt breccia. Flows of once-molten rock (gray) surround islands of less altered material. A small iron nickel nodule is seen at lower left. Credit: Bob King
A thin slice of Chelyabinsk impact melt breccia. Flows of once-molten rock (paler gray) surround islands of less altered material. A small iron nickel nodule is seen at lower left. Credit: Bob King

 

A closer look at Chelyabinsk meteorites reveals a fascinating story of ancient impact. Remarkably, the seeds of the meteoroid’s atmospheric destruction were sown 115 million years after the solar system’s formation when ur-Chelyabinsk was struck by another asteroid, suffering a powerful shock event that heated, fragmented and partially melted its interior. Look inside a specimen and the signs are everywhere – flows of melted rock, spider webby shock veins of melted silicates and peculiar, shiny cleavages called “slickensides” where meteorites broke along  pre-existing fracture planes.

Slickensides on a Chelyabinsk meteorite fragment where the fragment broke along a pre-existing fracture plane. Credit: Bob King
Slickensides on a Chelyabinsk meteorite fragment where the fragment broke along a pre-existing fracture plane. Credit: Bob King

Jenniskens calculated that the object may have come from the Flora family of S-type or stony asteroids in the belt between Mars and Jupiter. Somehow Chelyabinsk held together after the impact until nearly the time it met its fate with Earth’s atmosphere. Researchers at University of Tokyo and Waseda University in Japan discovered that the meteorite had only been exposed to cosmic rays for an unusually brief time for a Flora member – just 1.2 million years. Typical exposures are much longer and indicate that the Chelyabinsk parent asteroid only recently broke apart. Jenniskens speculates it was likely part of a loosely-bound, rubble pile asteroid that may have broken apart during a previous close encounter with Earth in the last 1.2 million years. The rest of the rubble pile might still be orbiting relatively nearby as part of the larger population of near-Earth asteroids.

Rivulets of melted rock line the fusion crust of melted rock on this small Chelyabinsk meteorite. Credit: Bob King
Rivulets of melted rock line the fusion crust of melted rock on this small Chelyabinsk meteorite. Credit: Bob King

Good thing Chelyabinsk arrived pre-fractured. Had it been solid through and through, more of the original asteroid might have survived its fiery descent and wreaked even more havoc in in its wake.

We’re fortunate that Chelyabinsk contains a fantastic diversity of features and that we have so many pieces for study. Surveys have found some 500 near-Earth asteroids. No doubt some are part of the parent body of Chelyabinsk and may grace our skies on some future date. Whatever happens, Feb. 15, 2013 will go down as a very loud “wake-up call” for our species to implement more asteroid-hunting programs both in space and on the ground. Enjoy a few more photos of this incredible gift from space:

This Chelyabinsk "nosecone" or "bullet" weighs just 0.35g. It displays a beautiful streamlined form from its flight through the atmosphere. Credit: Bob King
This Chelyabinsk “nosecone” or “bullet” weighs just 0.35g. It displays a beautiful streamlined form from its flight through the atmosphere. Credit: Bob King

Check out the bubble texture on this one. Heated by friction with the air, this fragment shows bubbly crust from escaping gases. Credit: Bob King
Check out the bubble texture on this one. Heated by friction with the air, this fragment shows bubbly crust from escaping gases. Credit: Bob King

Slice of Chelyabinsk showing relatively unshocked areas (light brown) cut by thick dark veins of shock-darkened material. Credit: Bob King
Slice of Chelyabinsk showing mildy shocked areas (light brown) cut by thick dark veins of shock-darkened material. Credit: Bob King

Some Chelyabinsk individuals show interesting variations in color that have nothing to do with rusting. It's believed that varying amounts of oxygen available to the speeding rocks during the meteorite break up created the brownish-red coloration on some fusion crusts. Credit: Bob King
Some Chelyabinsk individuals show interesting variations in color that have nothing to do with rusting. It’s believed that varying amounts of oxygen available to the speeding rocks during the meteorite break up created the brownish-red coloration on some fusion crusts. Credit: Bob King

OK, I saved the weirdest for last - a smaller Chelyabinsk meteorite appears to have followed closely enough behind the larger for there liquid fusion crusts to have welded them together. Just my speculation. Credit: Bob King
I saved the weirdest for last – a smaller Chelyabinsk meteorite appears to have followed closely enough behind the larger for their still-molten fusion crusts to have welded them together. Just my speculation. Credit: Bob King

Three-Meter Asteroid Hits Earth’s Atmosphere… Somewhere

Projected path of 2014 AA south of the Cape Verde islands. (Credit: Asteroid Initiatives, LLC)

This was very likely the last trip around the Sun for the Earth-crossing asteroid 2014 AA, according to calculations by several teams of astronomers and published online earlier today on the IAU’s Minor Planet Center. Discovered just yesterday by the Catalina Sky Survey, the estimated 3-meter-wide Apollo asteroid was supposed to clear Earth today by a razor-thin margin of about 611 km (380 miles)… but it’s now looking like it didn’t quite make it.

The diagram above, via Asteroid Initiatives’ Twitter feed, shows a projected path probability pattern for 2014 AA’s re-entry locations. No eyewitness accounts have yet been reported, and if anyone knows of any surveillance cameras aimed in those directions that might have captured footage of a bolide feel free to share that info below in the comments and/or with @AsteroidEnergy on Twitter.

Other calculations put the entry point anywhere between western Africa and Central America.

According to the MPEC report the asteroid “was unlikely to have survived atmospheric entry intact.”

Watch an animation below showing 2014 AA’s point-of-view as it met Earth. (Video courtesy of Pasquale Tricarico, senior scientist at the Planetary Science Institute in Tucson, AZ.)

2014 AA's approach to Earth on Jan. 1-2, 2014 (Pasquale Tricarico/PSI)
Simulation of 2014 AA’s approach to Earth on Jan. 1-2, 2014 (Credit: Pasquale Tricarico/PSI. Used with permission.)

JPL’s Near-Earth Object program classifies Apollo asteroids as “Earth-crossing NEAs with semi-major axes larger than Earth’s (named after asteroid 1862 Apollo).” And while not an Earth-shattering event (fortunately!) this is just another small reminder of why we need to keep watch on the sometimes-occupied path our planet takes around the Sun!

Read the NASA/JPL news release on 2014 AA here.

h/t to Dr. John Barentine for the heads-up!

UPDATE: Based on infrasound analysis by Peter Brown of the University of Western Ontario, 2014 AA likely impacted the atmosphere over the Atlantic around 0300 UTC at 40° west, 12° north — about 1,900 miles east of Caracas, Venezuela. The impact released the equivalent of 500 to 1,000 tons (0.5 – 1 kiloton) of TNT, but far above a remote and uninhabited area. Read more on Sky & Telescope here.

Remembering the Great Meteor Procession of 1860

Painting of The Meteor of 1860 by Hudson River School artist Frederic Church. (Credit: Frederic Church courtesy of Judith Filenbaum Hernstadt).

“Year of meteors! Brooding year!”

 -Walt Whitman

July 20th is a red letter date in space history. Apollo 11, the first crewed landing on the Moon, took place on this day in 1969. Viking 1 also made the first successful landing on Mars, seven years later to the day in 1976.

A remarkable astronomical event also occurred over the northeastern United States 153 years ago today on the night of July 20th, known as the Great Meteor Procession of 1860. And with it came a mystery of poetry, art and astronomy that was only recently solved in 2010.

A meteor procession occurs when an incoming meteor breaks up upon reentry into our atmosphere at an oblique angle. The result can be a spectacular display, leaving a brilliant glowing train in its wake. Unlike early morning meteors that are more frequent and run into the Earth head-on as it plows along in its orbit, evening meteors are rarer and have to approach the Earth from behind. In contrast, these often leave slow and stately trains as they move across the evening sky, struggling to keep up with the Earth.

The Great Meteor Procession of 1860 also became the key to unlock a 19th century puzzle as well. In 2010, researchers from Texas University San Marcos linked the event to the writings of one of the greatest American poets of the day.

Whitman...
Photograph of Walt Whitman taken by Mathew Brady circa 1860 (Library of Congress image in the Public Domain)..

Walt Whitman described a “strange, huge meteor-procession” in a poem entitled “Year of Meteors (1859-60)” published in his landmark work Leaves of Grass.

English professor Marilynn S. Olson and student Ava G. Pope teamed up with Texas state physics professors Russell Doescher & Donald Olsen to publish their findings in the July 2010 issue of Sky & Telescope.

As a seasoned observer, Whitman had touched on the astronomical in his writings before.

The event had previously been attributed over the years to the Great Leonid Storm of 1833, which a young Whitman would’ve witnessed as a teenager working in Brooklyn, New York as a printer’s apprentice.

Researchers noted, however, some problems with this assertion.

The stanza of contention reads;

Nor forget I sing of the wonder, the ship as she swam up my bay,

Well-shaped and stately, the Great Eastern swam up my bay, she was 600 feet long,

Her moving swiftly surrounded by myriads of small craft I forget not to sing;

Nor the comet that came unannounced out of the north flaring in heaven,

Nor the strange huge meteor-procession dazzling and clear shooting over our heads.

(A moment, a moment long, it sail’d its balls of earthly light over our heads,

Then departed, dropt in the night, and was gone.)

In the poem, the sage refers to the arrival of the Prince of Wales in New York City on October 1860. The election of Abraham Lincoln in November of that same year is also referred to earlier in the work.  Whitman almost seems to be making a cosmic connection similar to Shakespeare’s along the lines of “When beggars die, no comets are seen…

Path of the Meteor Procession of 1860 as depicted in the newspapers of the day. (From the collection of Don Olson).
Path of the Meteor Procession of 1860 as depicted in the newspapers of the day. (From the collection of Don Olson).

The “comet that came unannounced” is easily identified as the Great Comet of 1860. Also referred to as Comet 1860 III, this comet was discovered on June 18th of that year and reached +1st magnitude that summer as it headed southward. The late 19th century was rife with “great comets,” and northern hemisphere observers could look forward to another great cometary showing on the very next year in 1861.

The Great Comet of 1861 as drawn by G. Williams on June 30th, 1861. (From Descriptive Astronomy by George Chambers, 1877)
The Great Comet of 1861 as drawn by G. Williams on June 30th, 1861. (From Descriptive Astronomy by George Chambers, 1877)

There are some problems, however with the tenuous connection between the stanza and the Leonids.

The 1833 Leonids were one of the most phenomenal astronomical events ever witnessed, with estimates of thousands of meteors per second being seen up and down the U.S. Eastern Seaboard the morning of November 13th. Whitman himself described the event as producing;

“…myriads in all directions, some with long shining white trains, some falling over each other like falling water…”

Keep in mind, many startled townsfolk assumed their village was on fire on that terrifying morning in 1833, as Leonid bolides cast moving shadows into pre-dawn bedrooms. Churches filled up, as many thought that Judgment Day was nigh. The 1833 Leonids may have even played a factor in sparking many of the religious fundamentalist movements of the 1830s. We witnessed the 1998 Leonids from Kuwait, and can agree that this meteor shower can be a stunning sight at its peak.

But Whitman’s poem describes a singular event, a “meteor-procession” very different from a meteor shower.

Various sources have tried over the years to link the stanza to a return of the Leonids in 1858. A note from Whitman mentions a “meteor-shower, wondrous and dazzling (on the) 12th-13th, 11th month, year 58 of the States…” but keep in mind, “year 1” by this reckoning is 1776.

A lucky break came for researchers via the discovery of a painting by Frederic Church entitled “The Meteor of 1860.” This painting and several newspaper articles of the day, including an entry in the Harpers Weekly, collaborate a bright meteor procession seen across the northeastern U.S. from New York and Pennsylvania across to Wisconsin.

Such a bright meteor entered the atmosphere at a shallow angle, fragmented, and most likely skipped back out into space. Similar meteor processions have been observed over the years over the English Channel on August 18th, 1783 & across the U.S. Eastern Seaboard and Canada on February 9th, 1913.

On August 10th, 1972, a similar bright daylight fireball was recorded over the Grand Tetons in the western United States. Had the Great Meteor Procession of 1860 come in at a slightly sharper angle, it may have triggered a powerful airburst such as witnessed earlier this year over Chelyabinsk, Russia the day after Valentine’s Day.

The 1860 Meteor Procession is a great tale of art, astronomy, and mystery. Kudos to the team of researchers who sleuthed out this astronomical mystery… I wonder how many other unknown stories of historical astronomy are out there, waiting to be told?

Friday Night Lights: Fireball Lights Up the U.S. East Coast

Visibility map of the Manhattan meteor (American Meteor Society)

Last night a bright meteor was spotted up and down the northern mid-Atlantic United States from Maryland to Manhattan to Massachusetts. Streaking across the sky just before 8 p.m. EDT, the fireball was witnessed by thousands — the American Meteor Society alone has so far received over 630 reports on its website from the event. (Update 3/25: The AMS has received now over 1170 reports of the meteor.)

While many false images of the meteor quickly began circulating online, the video above is real — captured from a security camera in Thurmont, MD and uploaded to YouTube by Kim Fox (courtesy of Alan Boyle’s article on NBC News’ Cosmic Log.)

So what’s up with all these meteors lately?

According to NASA meteor specialist Bill Cooke, Friday’s fireball — which has become known as the “Manhattan meteor” — was likely caused by a boulder-sized asteroid about 3 feet (0.9 meters) wide entering Earth’s atmosphere. While bolides of this size sometimes result in meteorites that land on the ground, the last reports of the Manhattan meteor have it miles over the Atlantic… any pieces that survived entry and disintegration probably ended up in the ocean.

Here’s another video of the event from a Massachusetts news station.

And if you’re concerned about an apparent increase in the rate of meteors being spotted around the world, don’t be alarmed. Remember — spring is fireball season, after all.

“We’ve known about this phenomenon for more than 30 years. It’s not only fireballs that are affected. Meteorite falls–space rocks that actually hit the ground–are more common in spring as well.”

– Bill Cooke,  NASA’s Meteoroid Environment Center

So keep an eye on the sky over the next few weeks — you never know when we’ll be treated to another show!