We Saw It Coming: Dinky Asteroid Hits Earth, Burns Up
Jan 2, 2014 02:08 PM ET // by Ian O'Neill View Related Gallery »
Artist's impression of a small asteroid hitting the Earth’s upper atmosphere. Credit: Getty
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For only the second time in history, an asteroid has hit Earth that was discovered hours before impact. But don’t panic! The asteroid didn’t put a city-sized divot in our planet, it most likely burned up somewhere between Africa and South America over the Atlantic Ocean at midnight EST.
Asteroid 2014 AA, the first asteroid discovery of the year, was spotted by astronomers using the Mt. Lemmon Survey telescope in Arizona. As shrewdly pointed out by Bad Astronomer Phil Plait, the asteroid was the approximate size of a couch — measuring only a couple of meters across. That’s around one-half of a Mini Cooper, whichever takes your fancy. But whatever your preferred size comparison, the outcome was likely the same; the asteroid burned up on atmospheric entry as a meteor.
This might have provided a nice visual spectacle only a day after New Years, but 2014 AA is notable as being the first pre-impact discovery of an asteroid since 2008.
“2014 AA was unlikely to have survived atmospheric entry intact, as it was comparable in size to 2008 TC3, the only other example of an impacting object observed prior to atmospheric entry,” said a Minor Planet Electronic Circular announcement.
In 2008, 2008 TC3 was discovered hours before it disintegrated over Sudan. Knowing the precise time of impact and its approximate geographical location, meteorite hunters were able to find fragments of the fireball strewn over the desert. This was the first time an asteroid had been discovered, impact location predicted and fragments recovered from that location.
Although it’s unlikely that fragments from 2014 AA will be recovered from the ground (as the most likely region of reentry was off the western coast of Africa), this is a stunning achievement by asteroid hunters who were able to detect a tiny (and very faint) object approaching Earth and forecast the time and approximate location of impact. PHOTOS: Psychedelic Landscapes of Asteroid Vesta
As we learned from the Russian meteor event nearly a year ago, even comparatively small asteroids can wreak havoc if they slam into the skies over populated regions, so the techniques being developed to detect incoming space rocks could help us prepare — or even evacuate — a city if necessary.
Wow, there's nothing like an asteroid slamming into Earth to get professional and amateur astronomers whipped into a frenzy.
By tracking on the little asteroid 2008 TC3 before its impact, astronomers at the Clay Center observatory could watch it race across the sky. Click above to see a 300-Kb moving image. M. Kozubal & Ron Dantowitz / Clay Center Observatory
That's what happened on Monday morning when Maine skywatcher Bill Gray noticed something unique about a small asteroid discovered the previous night by Richard Kowalski and others at an observatory in Arizona. Gray's electronic posting to other asteroid aficionados began, "It looks as if Mt. Lemmon has found the first object . . . with a near certainty of hitting the earth."
Never mind that the object (designated 2008 TC3), was no bigger than a car, so in all likelihood it would explode harmlessly in the atmosphere with the kinetic-energy equivalent of 1,000 or 2,000 tons of TNT. That's no big deal as impacts go — objects of that size and energy hit somewhere on Earth every month or so.
Even so, the world's astronomers kicked into high gear, amassing 570 observations between the space rock's discovery until it slipped into Earth's shadow about an hour before impact. All that in just 19 hours! My email in box was lit up like a Christmas tree! As the observations piled up, dynamicists at JPL boldly announced that the mini-asteroid would slam into Earth at 2:46 Universal Time on October 7th. Ground zero was somewhere over northern Sudan — and at night! For anyone in that part of northeast Africa, it was going to be quite a show.
So what happened? The impact did occur as predicted, but so far there's no confirmation that anyone on the ground saw it. S&T contributing editor Johnny Horne, who's a photographer for the Fayetteville Observer, received a negative report from Khartoum, Sudan's capital. Khartoum and Mecca are the closest significant cities to the impact site, but each is still roughly 300 miles away. This part of the world is exceedingly arid and sparsely populated — people living there have far bigger issues on their minds.
Nor have we received any confirmed sightings from countless observers in Europe who went out in the hopes of seeing the flash.
However, Peter Brown, a meteor researcher at the University of West Ontario, reports that the airburst was recorded by at least one infrasound sensor operated by the International Monitoring System, whose primary purpose is detecting surreptitious nuclear tests. Brown confirms that the impact energy ranged from 1,100 to 2,100 tons of TNT.
Visually, the most compelling evidence comes from nighttime visual and infrared images acquired by the European Space Agency's Meteosat 8 weather satellite. Zdenek Charvat (Czech Hydrometeorological Institute), who first noticed the flash in the Meteosat images, reports that the spot is apparent in all 12 spectral channels, which span wavelengths from 0.5 to 14 microns).
But the satellite's scanning imager takes about 5 minutes to record each frame, so there's no way to extract the exact time of the spot's appearance. But the flare seems to be in the right spot, corresponding to longitude 32.37° east and latitude +20.89° and an altitude of 14 to 20 miles (22 to 30 km). One frame hints at an apparent trail about 2 miles long.
This sequence, which combines images taken every 4 seconds, records the asteroid's dramatic changes in brightness that signified its tumbling motion. M. Kozubal & Ron Dantowitz / Clay Center Observatory
Meanwhile, telescopic observations show that 2008 TC3 was gyrating wildly before it hit. According to Czech asteroid specialist Petr Pravec, it was "definitely a tumbler." His analysis reveals two distinct periods of 49 and 98 seconds long. One is probably due to rotation and the other to spin-axis precession, but he can't tell yet which is which. But he notes that this ranks (or ranked!) as one of the three fastest-spinning asteroids known.
"It would be good to mention the role of Marek Kozubal and Ron Dantowitz at the Clay Center Observatory" Pravec told me. "Their photometric observations of the asteroid have been unique, and without them we wouldn't know much about its rotation."
I don't think we've heard the last word on this little party-crasher. After all, the U.S. Department of Defense has "assets" well suited to recording explosions in that part of the world. And from time to time the DoD's scientists have shared what they know with their civilian counterparts. So stay tuned for further developments!
You can read our original announcement about this asteroid here.
Posted by Kelly Beatty, October 9, 2008
related content: Solar system
In case you missed it Friday night, a massive asteroid passed our little blue world, thankfully without incident.
To be honest it wasn’t really going to come that close, but aren’t you glad our peepers in the sky and on the ground are keeping a watchful eye out for these occurrences? The 400ft wide rock was noticed on December 23, 2013 with scientists believing it would make its closest approach to Earth on January 3, 2014. Asteroid watchers were able to make their calculations based on some 50 different observation over six days.
Keep in mind, by close we mean 3.6 lunar distances (or some 1,400,000 km), so there is no threat of wiping out all life as we know it in some kind of Deep Impact inspired scenario. This is not the first “near miss” that Earth has seen. For example in 2012 another near miss (by 140,000 miles) occurred in early December by the XE54, which was some 120 ft wide. An asteroid of similar size destroyed over 800 miles of forest in Siberia in 1908.
Scientists have discovered some 9,000 asteroids with the possibility to be potentially dangerous, which is higher than one might expect. NASA’s WISE (Wide-Field Infrared Survey Explorer) observations indicate that nearly 5,000 asteroids of considerable size come within an alarmingly close distance to the Earth in their respective orbits, 30% of that number having the capability of destroying a substantial area if they were to impact the planet. For example, the Toutatis Asteroid is 3 miles wide, and the closest it has come to Earth is 4.5 million miles, but it still bears monitoring.
After all, the asteroid that that killed off the dinosaurs and kicked off a global ice age was some six miles wide. You would think we would have little to worry about, but when you consider the damage that some of the smaller impacts over the years have caused, it’s comforting to know that somebody is watching and possibly expecting the worst.
Asteroid may have killed dinosaurs quicker than scientists thought
By Irene Klotz
CAPE CANAVERAL, Florida Fri Feb 8, 2013 4:56am EST
Image courtesy of NASA shows an artist's concept of a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs.
Credit: Reuters/NASA/JPL-Caltech/Handout
(Reuters) - Dinosaurs died off about 33,000 years after an asteroid hit the Earth, much sooner than scientists had believed, and the asteroid may not have been the sole cause of extinction, according to a study released Thursday.
Earth's climate may have been at a tipping point when a massive asteroid smashed into what is now Mexico's Yucatan Peninsula and triggered cooling temperatures that wiped out the dinosaurs, researchers said.
The time between the asteroid's arrival, marked by a 110-mile-(180-km-)wide crater near Chicxulub, Mexico, and the dinosaurs' demise was believed to be as long as 300,000 years.
The study, based on high-precision radiometric dating techniques, said the events occurred within 33,000 years of each other.
Other scientists had questioned whether dinosaurs died before the asteroid impact.
"Our work basically puts a nail in that coffin," geologist Paul Renne of the University of California Berkeley said.
The theory that the dinosaurs' extinction about 66 million years ago was linked to an asteroid impact was first proposed in 1980. The biggest piece of evidence was the so-called Chicxulub (pronounced "cheek'-she-loob") crater off the Yucatan coast in Mexico.
It is believed to have been formed by a six-mile-(9.6-km-) wide object that melted rock as it slammed into the ground, filling the atmosphere with debris that eventually rained down on the planet. Glassy spheres known as tektites, shocked quartz and a layer of iridium-rich dust are still found around the world today.
Renne and colleagues reanalyzed both the dinosaur extinction date and the crater formation event and found they occurred within a much tighter window in time than previously known. The study looked at tektites from Haiti, tied to the asteroid impact site, and volcanic ash from the Hell Creek Formation in Montana, a source of many dinosaur fossils.
NEW DATING TECHNIQUE
"The previous data that we had ... actually said that they (the tektites and the ash) were different in age, that they differed by about 180,000 years and that the extinction happened before the impact, which would totally preclude there being a causal relationship," said Renne, who studies ties between mass extinctions and volcanism.
He and colleagues were comparing a new technique to date geologic events when they realized there was a discrepancy in the timing - the so-called 'K-T boundary' - the geological span of time between the Cretaceous and Paleocene periods when the dinosaurs and most other life on Earth died out.
"I realized there was a lot of room for improvement. Even though many people had locked in their opinions that the impact and the extinctions were synchronous or not, they were basically ignoring the existing data," Renne said.
The study, published in Science, resolves existing uncertainty about the relative timing of the events, notes Heiko Pälike of the Center for Marine Environmental Sciences at the University of Bremen, Germany.
Renne, for one, does not believe the asteroid impact was the sole reason for the dinosaurs' demise. He says ecosystems already were in a state of deterioration due to a major volcanic eruption in India when the asteroid struck.
The asteroid strike "provided the coup-de-grace for the final extinctions," Renne said, adding that the theory was speculative, but backed by previous ties between mass extinction events and volcanic eruptions.
About 1 million years before the impact, Earth experienced six abrupt shifts in temperature of more than 2 degrees in continental mean annual temperatures, according to research cited by Renne and his co-authors.
The temperature swings include one shift of 6 to 8 degrees that happened about 100,000 years before the extinction.
"The brief cold snaps in the latest Cretaceous, though not necessarily of extraordinary magnitude, were particularly stressful to a global ecosystem that was well adapted to the long-lived preceding Cretaceous hothouse climate. The Chicxulub impact then provided a decisive blow to ecosystems," Renne and his co-authors wrote in Science.
A NASA spacecraft has spotted a “potentially hazardous” asteroid nearly half a mile wide barreling in the general direction of Earth.
The asteroid, named “2013 YP139″, is very dark, 0.4 miles across, and could come almost as close to the Earth as our moon, based on current projections. The rock has earned NASA’s “potentially hazardous” distinction due to its size and projected flight path.
But there’s no need to call Bruce Willis and the rest of the team from “Armageddon” just yet. The asteroid is still 27 million miles away from Earth, and won’t get here for another hundred years at least.
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Nasa: Giant asteroid could come ‘close’ to Earth
Thursday 9 Jan 2014 9:11 am
Share on Facebook Share on Twitter Asteroid 2013 YP139 has been spotted by Neowise (Picture: Nasa) Nasa’s asteroid-hunting telescope has spotted its first potential threat.
Neowise located the 640m wide (2,100ft) rock, named 2013 YP139, about 27million miles from Earth.
Its orbit could bring it to within 300,000 miles of Earth, slightly more than the distance to the Moon.
Nasa says a hit by an asteroid any larger than 800m in diameter could have devastating effects.
Scientists said 2013 YP139’s long-term motion was being closely monitored to see how close it may come to Earth.
Neowise was put into ‘hibernation’ by Nasa in 2011 after it completed its mission of surveying the sky in infrared light.
It was reactivated last August to start a new mission to find and characterise asteroids.
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NEOWISE Bags Its First Asteroid!
By Phil Plait
The near-Earth asteroid 2013 YP139 can be seen gliding through this composite NEOWISE image (red circles), with one shot highlighted at the bottom. Click to armageddonate.
asteroid 2013 YP139 The near-Earth asteroid 2013 YP139 can be seen gliding through this composite NEOWISE image (red circles), with one shot highlighted at the bottom. Click to armageddonate.
Photo by NASA/JPL-Caltech
NEOWISE, NASA’s reanimated infrared space mission, has found its first asteroid!
Phil Plait Phil Plait
Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death from the Skies! Follow him on Twitter.
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Well, that didn’t take long. Not that I expected it would.
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Called 2013 YP139, the rock is about 650 meters (0.4 miles) across. It’s on a highly elliptical orbit that takes it out from the Sun past Mars, and back in to just inside the Earth’s orbit. It’s actually a near-Earth asteroid; it can potentially swing by as close as 500,000 kilometers (300,000 miles) from our planet, a bit farther out than the Moon. The orbit is still uncertain right now, but rest easy: It seems likely it won’t get anywhere near the Earth for quite some time, probably a century or so.
orbit of YP139 The orbit of 2013 YP139 takes it just inside Earth's own orbit; it's currently about 40 million kilometers away.
Graphic by Photo by NASA/JPL-Caltech
NEOWISE stands for the Near-Earth Object Wide-field Infrared Survey Explorer. It used to be just WISE when it first launched; it operated for about a year, surveying the sky in infrared. It took amazing images of gas clouds, galaxies, and asteroids. Especially asteroids; they glow in the infrared and are actually easier to see in IR than visible light.
WISE ran out of coolant after a year in orbit. However, NASA decided to resurrect the mission, repurposing it to look for potentially hazardous asteroids (and no doubt wanting to tie it in with their plans to capture an asteroid as well). In September 2013 it was switched back on, its name was changed, and the hunt began anew.
NEOWISE started seeing asteroids right away, but it wasn’t until Dec. 29 that it found YP139, its first new one (that is, one never observed before). An added benefit to using NEOWISE for this search is that asteroid sizes are easier to determine when they’re observed in the IR. In visible light, a big dark rock can masquerade as a smaller, shinier one, but in the infrared they can’t hide their size. The more we know about each individual asteroid, obviously, the better.
NEOWISE is also paving the way for a next generation asteroid hunter called NEOCam, the Near-Earth Object Camera. This is already being tested at NASA’s JPL and will scan the skies looking for potential Earth impactors. Together with the B612 Foundation’s Sentinel mission, in the next few years we may finally start getting serious about looking for rocks with our name on them. Oddly enough, I’m all for this.
YP139 may be the first, but astronomers expect to find hundreds more over the next few years. My congratulations to my pal Amy Mainzer, the NEOWISE principal investigator, and the team that made this mission possible!
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Don't think that's a real photo of the actual asteroid.... it's just a photo.
NASA discovers new potentially hazardous asteroid
PTI [ Updated 09 Jan 2014, 12:09:01 ]
Washington: NASA's latest sky-mapping spacecraft has discovered a new potentially hazardous asteroid, 43 million kilometres from Earth.
It is the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE)'s first such discovery since coming out of hibernation last year.
The spacecraft discovered a near-Earth asteroid designated 2013 YP139 on December 29. The mission's sophisticated software picked out the moving object against a background of stationary stars.
As NEOWISE circled Earth scanning the sky, it observed the asteroid several times over half a day before the object moved beyond its view.
Researchers at the University of Arizona used the Spacewatch telescope at the Kitt Peak National Observatory southwest of Tucson to confirm the discovery.
NASA expects 2013 YP139 will be the first of hundreds of asteroid discoveries for NEOWISE.
"We are delighted to get back to finding and characterising asteroids and comets, especially those that come into Earth's neighbourhood," said Amy Mainzer, the mission's principal investigator from NASA's Jet Propulsion Laboratory in Pasadena, California.
Re: Asteroids: Close and Closer
View Related Gallery »
By tracking on the little asteroid 2008 TC3 before its impact, astronomers at the Clay Center observatory could watch it race across the sky. Click above to see a 300-Kb moving image.
This sequence, which combines images taken every 4 seconds, records the asteroid's dramatic changes in brightness that signified its tumbling motion.
By: Mark Williams 01/05/14
Image courtesy of NASA shows an artist's concept of a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs.
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