Lecturer at Ural Federal University's Institute of Physics and Technology Viktor Grokhovsky with meteorite fragment found during an expedition in the Chelyabinsk region on February 25, 2013. Credit: RIA Novosti / Pavel Lysizin.
Scientists and meteorites hunters have been on a quest to find bits of rock from the asteroid which exploded over the city of Chelyabinsk in Russia on February 15. More than 100 fragments have been found so far that appear to be from the space rock, and now scientists from Russia’s Urals Federal University have discovered the biggest chunk so far, a meteorite fragment weighing more than one kilogram (2.2 lbs).
The asteroid has been estimated to be about 15 meters (50 feet) in diameter when it struck Earth’s atmosphere, traveling several times the speed of sound, and exploded into a fireball, sending a shockwave to the city below, which broke windows and caused other damage to buildings, injuring about 1,500 people.
A hole in Chebarkul Lake made by meteorite debris. Photo by Chebarkul town head Andrey Orlov. Via RT.com
Fragments of the meteorite have been found along a 50 kilometer (30 mile) trail under the meteorite’s flight path. Small meteorites have also been found in an eight-meter (25 feet) wide crater in the region’s Lake Chebarkul, scientists said earlier this week. Viktor Grokhovsky from the Urals University believes there are more to be found, including a possible biggest chunk that he says may lie at the bottom of Lake Chebarkul. It could be up to 60cm in diameter, he estimated.
This video from NASA explains more:
Please note that while many pieces have been found, and if you are looking to buy a chunk of this famous meteorite, you need to approach this with a lot of skepticism. There have been some reports of people trying to sell pieces that they claim to be from the Ural/Russian meteorite, but they likely are not. Be careful and do your research on the seller before you buy.
econstructed orbits for the Chelyabinsk meteoroid. Credit: Jorge Zuluaga and Ignacio Ferrin, University of Antioquia in Medellin, Colombia
Just a week after a huge fireball streaked across the skies of the Chelyabinsk region of Russia, astronomers published a paper that reconstructs the orbit and determines the origins of the space rock that exploded about 14-20 km (8-12.5 miles) above Earth’s surface, producing a shockwave that damaged buildings and broke windows.
Researchers Jorge Zuluaga and Ignacio Ferrin at the University of Antioquia in Medellin, Colombia used a resource not always available in meteorite falls: the numerous dashboard and security cameras that captured the huge fireball. Using the trajectories shown in videos posted on YouTube, the researchers were able to calculate the trajectory of the meteorite as it fell to Earth and use it to reconstruct the orbit in space of the meteoroid before its violent encounter with our planet.
The results are preliminary, Zuluaga told Universe Today, and they are already working on getting more precise results. “We are working hard to produce an updated and more precise reconstruction of the orbit using different pieces of evidence,” he said via email.
But through their calculations, Zuluaga and Ferrin determined the rock originated from the Apollo class of asteroids.
Using triangulation, the researchers used two videos specifically: one from a camera located in the Revolutionary Square in Chelyabinsk and one video recorded in the a nearby city of Korkino, along with the location of a hole in the ice in Lake Chebarkul, 70km west of Chelyabinsk. The hole is thought to have come from the meteorite that fell on February 15.
Zuluaga and Ferrin were inspired to use the videos by Stefen Geens, who writes the Ogle Earth blog and who pointed out that the numerous dashcam and security videos may have gathered data about the trajectory and speed of the meteorite. He used this data and Google Earth to reconstruct the path of the rock as it entered the atmosphere and showed that it matched an image of the trajectory taken by the geostationary Meteosat-9 weather satellite.
But due to variations in time and date stamps on several of the videos — some which differed by several minutes — they decided to choose two videos from different locations that seemed to be the most reliable.
From triangulation, they were able to determine height, speed and position of the meteorite as it fell to Earth.
This video is a virtual exploration of the preliminary orbit computed by Zuluaga & Ferrin
But figuring out the meteroid’s orbit around the Sun was more difficult as well as less precise. They needed six critical parameters, all which they had to estimate from the data using Monte Carlo methods to “calculate the most probable orbital parameters and their dispersion,” they wrote in their paper. Most of the parameters are related to the “brightening point” – where the meteorite becomes bright enough to cast a noticeable shadow in the videos. This helped determine the meteorite’s height, elevation and azimuth at the brightening point as well as the longitude, latitude on the Earth’s surface below and also the velocity of the rock.
“According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere,” the team wrote. “The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers.”
They then used software developed by the US Naval Observatory called NOVAS, the Naval Observatory Vector Astrometry to calculate the likely orbit. They concluded that the Chelyabinsk meteorite is from the Apollo asteroids, a well-known class of rocks that cross Earth’s orbit.
According to The Technology Review blog, astronomers have seen over 240 Apollo asteroids that are larger than 1 km but believe there must be more than 2,000 others that size.
However, astronomers also estimate there might be about 80 million out there that are about same size as the one that fell over Chelyabinsk: about 15 meters (50 feet) in diameter, with a weight of 7,000 metric tons.
In their ongoing calculations, the research team has decided to make future calculations not using Lake Chebarkul as one of their triangulation points.
“We are acquainted with the skepticism that the holes in the icesheet of the lake have been produced artificially,” Zuluaga told Universe Today via email. “However I have also read some reports indicating that pieces of the meteoroid have been found in the area. So, we are working hard to produce an updated and more precise reconstruction of the orbit using different pieces of evidence.”
Many have asked why this space rock was not detected before, and Zuluaga said determining why it was missed is one of the goals of their efforts.
“Regretfully knowing the family at which the asteroid belongs is not enough,” he said. “The question can only be answered having a very precise orbit we can integrate backwards at least 50 years. Once you have an orbit, that orbit can predict the precise position of the body in the sky and then we can look for archive images and see if the asteroid was overlooked. This is our next move!”
A polished slice of one of Russian meteorite samples. You can see round grains called chondrules and shock veins lined with melted rock. The meteorite is probably non-uniform. The preliminary analysis showed that the meteorite belongs to chemical type L or LL, petrologic type 5.
A little more than week ago a 7,000 ton, 50-foot (15-meter) wide meteoroid made an unexpected visit over Russia to become the biggest space rock to enter the atmosphere since the Tunguska impact in 1908. While scientists still debate whether it was asteroid or comet that sent a tree-flattening shockwave over the Tunguska River valley, we know exactly what fell last Friday.
Now is a fitting time to get more familiar with these extraterrestrial rocks that drop from out of nowhere.
The Russian meteoroid – the name given an asteroid fragment before it enters the atmosphere – became a brilliant meteor during its passage through the air. If a cosmic rock is big enough to withstand the searing heat and pressure of entry, fragments survive and fall to the ground as meteorites. Most of the meteors or “shooting stars” we see on a clear night are bits of rock the size of apple seeds. When they strike the upper atmosphere at tens of thousands of miles an hour, they vaporize in a flash of light. Case closed. But the one that boomed over the city of Chelyabinsk was big enough to to survive its last trip around the Sun and sprinkle the ground with meteorites.
The two main smoke trails left by the Russian meteor as it passed over the city of Chelyabinsk. Credit: AP Photo/Chelyabinsk.ru
Ah, but the Russian fireball didn’t get off the hook that easy. The overwhelming air pressure at those speeds combined with re-entry temperatures around 3,000 degrees F (1,650 C) shattered the original space rock into many pieces. You can see the dual trails created by two of the larger hunks in the photo above.
Scientists at Urals Federal University in Yekaterinburg examined 53 small meteorite fragments deposited around a hole in ice-covered Chebarkul Lake 48 miles (77 km) west of Chelyabinsk the following day. Chemical analysis revealed the stones contained 10% iron-nickel metal along with other minerals commonly found in stony meteorites. Since then, hundreds of fragments have been dug out of the snow by people in surrounding villages. As specimens continue to be recovered and analyzed, here’s an overview — and a look at what we know — of these space rocks that pay us a visit from time to time.
Bright fireball breaking up over Yellow Springs, Ohio. Credit: John Chumack
How many times has a meteor taken your breath away? A brilliant fireball streaking across the night sky ranks among the most memorable astronomical sights most of us will ever see. Like objects in your side view mirror, meteors appear closer than they really are. And it’s all the more true when they’re exceptionally bright. Studies show however that meteors burn up at least 50 miles (80 km) overhead. If big enough to remain intact and land on the ground, the fragments go completely dark 5-12 miles (8-19 km) high during the “dark flight” phase. A meteor passing overhead would be at the minimum distance of about 50 miles (80 km) from the observer.
Since most sightings are well off toward one direction or another, you have to add your horizontal distance to the meteor’s height to get a true distance. While some meteors are bright enough to trick us into thinking they landed just over the next hill, nearly all are many miles away. Even the Russian meteor, which put on a grand show and blasted the city of Chelyabinsk with a powerful shock wave, dropped fragments dozens of miles to the west. We lack the context to appreciate meteor distances, perhaps unconsciously comparing what we see to an aerial fireworks display.
Very cute Youtube video of Sasha Zarezina, 8, who lives in a small Siberian village, as she hunts for meteorite fragments in the snow after Friday’s meteor over Russia. Credit: Ben Solomon/New York Times
An estimated 1,000 tons (907 metric tons) to more than 10,000 tons (9,070 MT) of material from outer space lands on Earth every day delivered free of charge from the main Asteroid Belt. Crack-ups between asteroids in the distant past are nudged by Jupiter into orbits that cross that of Earth’s. Most of the stuff rains down as micrometeoroids, bits of grit so small they’re barely touched by heating as they gently waft their way to the ground. Many larger pieces – genuine meteorites – make it to Earth but are missed by human eyes because they fall in remote mountains, deserts and oceans. Since over 70% of Earth’s surface’s is water, think of all the space rocks that must sink out of sight forever.
A fragment of the Sikhote-Alin iron meteorite that fell over eastern Russia (then the Soviet Union) on Feb. 12, 1947. Credit: Bob King
About 6-8 times a year however, a meteorite-producing fireball streaks over a populated area of the world. Using eyewitness reports of time, direction of travel along with more modern tools like video surveillance cameras and Doppler weather radar, which can ping the tracks of falling meteorites, scientists and meteorite hunters have a great many clues on where to look for space rocks.
Since most meteorites break into pieces in mid-air, the fragments are dispersed over the ground in a large oval called the strewnfield. The little pieces fall first and land at the near end of the oval; the bigger chunks travel farthest and fall at the opposite end.
When a new potential meteorite falls, scientists are eager to get a hold of pieces as soon as possible. Back in the lab, they measure short-lived elements called radionuclides created when high-energy cosmic rays in space alter elements in the rock. Once the rock lands on Earth, creation of these altered elements stops. The proportions of radionuclides tell us how long the rock traveled through space after it was ejected by impact from its mother asteroid. If a meteorite could write a journal, this would be it.
Other tests that examine the decay of radioactive elements like uranium into lead tells us the age of the meteorite. Most are 4.57 billion years old. Hold a meteorite and you’ll be whisked back to a time before the planets even existed. Imagine no Earth, no Jupiter.
10x closeup of a very thin slice through a chondrule in the meteorite NWA 4560. Crystals of olivine (bright colors) and pyroxene (grays) are visible. Credit: Bob King
Many meteorites are jam-packed with tiny rocky spheres called chondrules. While their origin is still a topic of debate, chondrules (KON-drools) likely formed when blots of dust in the solar nebula were flash-heated by the young sun or perhaps by powerful bolts of static electricity. Sudden heating melted the motes into chondrules which quickly solidified. Later, chondrules agglomerated into larger bodies that ultimately grew into planets through mutual gravitational attraction. You can always count on gravity to get the job done. Oh, just so you know, meteorites are no more radioactive than many common Earth rocks. Both contain trace amounts of radioactive elements at trifling levels.
A stunning slice of the Glorieta pallasite meteorite cut thin enough to allow light to shine through its many olivine crystals. Click to see more of Mike’s photos. Credit: Mike Miller
Meteorites fall into three broad categories – irons (mostly metallic iron with smaller amounts of nickel), stones (composed of rocky silicates like olivine, pyroxene and plagioclase and iron-nickel metal in form of tiny flakes) and stony-irons (a mix of iron-nickel metal and silicates). The stony-irons are broadly subdivided into mesosiderites, chunky mixes of metal and rock, and pallasites.
Pallasites are the beauty queens of the meteorite world. They contain a mix of pure olivine crystals, better known as the semi-precious gemstone peridot, in a matrix of iron-nickel metal. Sliced and polished to a gleaming finish, a pallasite wouldn’t look out of place dangling from the neck of an Oscar winner. About 95% of all found or seen-to-fall meteorites are the stony variety, 4.4% are irons and 1% stony-irons.
A slice of the NWA 5205 meteorite from the Sahara Desert displays wall-to-wall chondrules. Credit: Bob King
Earth’s atmosphere is no friend to space rocks. Collecting them early prevents damage by the two things most responsible for keeping us alive: water and oxygen. Unless a meteorite lands in a dry desert environment like the Sahara or the “cold desert” of Antarctica, most are easy prey to the elements. I’ve seen meteorites collected and sliced open within a week after a fall that already show brown stains from rusting nickel-iron. Antarctica is off-limits to all but professional scientists, but thanks to amateur collectors’ efforts in the Sahara Desert, Oman and other regions, thousands of meteorites including some of the rarest types, have come to light in recent years.
Greg Hupe, renowned meteorite hunter, wears a big smile after finding a fresh 33.7g meteorite of the Mifflin, Wis. fall in 2010. Credit: Greg Hupe
Hunters share their finds with museums, universities and through outreach efforts in the schools. A portion of the material is sold to other collectors to finance future expeditions, pay for plane tickets and sit down to a good meal after the hunt. Finding a meteorite of your own is hard but rewarding work. If you’d like to have a go at it, here’s a basic checklist of qualities that separate space rocks from Earth rocks:
* Attracts a magnet. Most meteorites – even stony ones – contain iron.
* Most are covered with a matt-black, slightly bumpy fusion crust that colors dark brown with age. Look for hints of rounded chondrules or tiny bits of metal sticking up through the crust.
* Aerodynamic shape from its flight through the atmosphere, but be wary of stream-eroded rocks which appear superficially similar
* Some are dimpled with small thumbprint-like depressions called regmaglypts. These form when softer materials melt and stream away during atmospheric entry. Some meteorites also display hairline-thin, melted-rock flow lines rippling across their exteriors.
Beware of imitations! These are chunks of industrial slag that are often confused with real meteorites. Meteorites don’t have bubbly surfaces. Credit: Bob King
Should your rock passes the above tests, file off an edge and look inside. If the interior is pale with shining flecks of pure metal (not mineral crystals), your chances are looking better. But the only way to be certain of your find is to send off a piece to a meteorite expert or lab that does meteorite analysis. Industrial slag with its bubbly crust and dark, smooth volcanic rocks called basalts are the most commonly found meteor-wrongs. We imagine that meteorites must have bubbly crust like a cheese pizza; after all, they’ve been oven-baked by the atmosphere, right? Nope. Heating only happens in the outer millimeter or two and crusts are generally quite smooth.
Look Ma, no chondrules. NWA 3147 is an achondrite eucrite meteorite that probably originated from the asteroid Vesta. Credit: Bob King
Stony meteorites are further subdivided into two broad types – chondrites, like the Russian fall, and achondrites, so-called because they lack chondrules. Achondrites are igneous rocks formed from magma deep within an asteroid’s crust and lava flows on the surface. Some eucrites (YOU-crites), the most common type of achondrite, likely originated as fragments shot into space from impacts on Vesta. Measurements by NASA’s Dawn space mission, which orbited the asteroid from July 2011 to September 2012, have found great similarities between parts of Vesta’s crust and eucrites found on Earth.
We also have meteorites from Mars and the Moon. They got here the same way the rest of them did; long-ago impacts excavated crustal rocks and sent them flying into space. Since we’ve studied moon rocks brought back by the Apollo missions and sampled Mars atmosphere with a variety of landers, we can compare minerals and gases found inside potential moon and Mars meteorites to confirm their identity.
Some of the 53 chondrite meteorites found around Chebarkul Lake. Many are coated with a thin crust of melted and blackened rock heating by the atmosphere. The sign reads: Meteorite Chebarkul. Credit: AP / The Urals Federal University Press Service, Alexander Khlopotov
Scientists study space rocks for clues of the Solar System’s origin and evolution. For the many of us, they provide a refreshing “big picture” perspective on our place in the Universe. I love to watch eyes light up with I pass around meteorites in my community education astronomy classes. Meteorites are one of the few ways students can “touch” outer space and feel the awesome span of time that separates the origin of the Solar System and present day life.
US-European Asteroid Impact and Deflection mission – AIDA.
Planetary Defense is a concept very few people heard of or took seriously – that is until last week’s humongous and totally unexpected meteor explosion over Russia sent millions of frightened residents ducking for cover, followed just hours later by Earth’s uncomfortably close shave with the 45 meter (150 ft) wide asteroid named 2012 DA14.
This ‘Cosmic Coincidence’ of potentially catastrophic space rocks zooming around Earth is a wakeup call that underscores the need to learn much more about the ever present threat from the vast array of unknown celestial debris in close proximity to Earth and get serious about Planetary Defense from asteroid impacts.
The European Space Agency’s (ESA) proposed Asteroid Impact and Deflection Assessment mission, or AIDA, could significantly bolster both our basic knowledge about asteroids in our neighborhood and perhaps even begin testing Planetary Defense concepts and deflection strategies.
After two years of work, research teams from the US and Europe have selected the mission’s target – a so called ‘binary asteroid’ named Didymos – that AIDA will intercept and smash into at about the time of its closest approach to Earth in 2022 when it is just 11 million kilometers away.
“AIDA is not just an asteroid mission, it is also meant as a research platform open to all different mission users,” says Andres Galvez, ESA studies manager.
Asteroid Didymos could provide a great platform for a wide variety of research endeavors because it’s actually a complex two body system with a moon – and they orbit each other. The larger body is roughly 800 meters across, while the smaller one is about 150 meters wide.
Didymos with its Moon. Credit: ESA
So the smaller body is some 15 times bigger than the Russian meteor and 3 times the size of Asteroid 2012 DA14 which flew just 27,700 km (17,200 mi) above Earth’s surface on Feb. 15, 2013.
The low cost AIDA mission would be comprised of two spacecraft – a mother ship and a collider. Two ships for two targets.
The US collider is named the Double Asteroid Redirection Test, or DART and would smash into the smaller body at about 6.25 km per second. The impact should change the pace at which the objects spin around each other.
ESA’s mothership is named Asteroid Impact Monitor, or AIM, and would carry out a detailed science survey of Didymos both before and after the violent collision.
“The project has value in many areas,” says Andy Cheng, AIDA lead at Johns Hopkins’ Applied Physics Laboratory, “from applied science and exploration to asteroid resource utilisation.” Cheng was a key member of NASA’s NEAR mission that first orbited and later landed on the near Earth Asteroid named Eros back in 2001.
Recall that back in 2005, NASA’s Deep Impact mission successfully lobbed a projectile into Comet Tempel 1 that unleashed a fiery explosion and spewing out vast quantities of material from the comet’s interior, including water and organics.
NASA’s Deep Impact images Comet Tempel 1 alive with light after colliding with the impactor spacecraft on July 4, 2005. ESA and NASA are now proposing the AIDA mission to smash into Asteroid Didymos. CREDIT: NASA/JPL-Caltech/UMD
ESA has invited researchers to submit AIDA experiment proposals on a range of ideas including anything that deals with hypervelocity impacts, planetary science, planetary defense, human exploration or innovation in spacecraft operations. The deadline is 15 March.
“It is an exciting opportunity to do world-leading research of all kinds on a problem that is out of this world,” says Stephan Ulamec from the DLR German Aerospace Center. “And it helps us learn how to work together in international missions tackling the asteroid impact hazard.”
The Russian meteor exploded without warning in mid air with a force of nearly 500 kilotons of TNT, the equivalent of about 20–30 times the atomic bombs detonated at Hiroshima and Nagasaki.
Over 1200 people were injured in Russia’s Chelyabinsk region and some 4000 buildings were damaged at a cost exceeding tens of millions of dollars. A ground impact would have decimated cities like New York, Moscow or Beijing with millions likely killed.
ESA’s AIDA mission concept and NASA’s approved Osiris-REx asteroid sample return mission will begin the path to bolster our basic knowledge about asteroids and hopefully inform us on asteroid deflection and Planetary Defense strategies.
'Name That Space Rock' -- describes the difference between those flying rocks from space. Credit and copyright: Tim Lilis. Used by permission.
With all the various space rocks flying by and into Earth last Friday, perhaps you’ve been wondering about the correct terminology, since a rock from space has different names depending on what it is made of and where it is.
Infographics artist Tim Lillis has put together a primer of sorts, in the form of an infographic, describing the different between a comet, asteroid, meteoroid, meteor and meteorite.
Asteroids are generally larger chunks of rock that come from the asteroid belt located between the orbits of Mars and Jupiter. Sometimes their orbits get perturbed or altered and some asteroids end up coming closer to the Sun, and therefore closer to Earth.
Comets are much like asteroids, but might have a more ice, methane, ammonia, and other compounds that develop a fuzzy, cloud-like shell called a coma – as well as a tail — when it gets closer to the Sun. Comets are thought to originate from two different sources: Long-period comets (those which take more than 200 years to complete an orbit around the Sun) originate from the Oort Cloud. Short-period comets (those which take less than 200 years to complete an orbit around the Sun) originate from the Kuiper Belt.
Space debris smaller than an asteroid are called meteoroids. A meteoroid is a piece of interplanetary matter that is smaller than a kilometer and frequently only millimeters in size. Most meteoroids that enter the Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface. And when they do enter Earth’s atmosphere, they gain a different name:
Meteors. Another name commonly used for a meteor is a shooting star. A meteor is the flash of light that we see in the night sky when a small chunk of interplanetary debris burns up as it passes through our atmosphere. “Meteor” refers to the flash of light caused by the debris, not the debris itself.
If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite. Although the vast majority of meteorites are very small, their size can range from about a fraction of a gram (the size of a pebble) to 100 kilograms (220 lbs) or more (the size of a huge, life-destroying boulder).
Thanks again to Tim Lillis for sharing his infographic with Universe Today. For more info about Tim’s work, see his Behance page, Flickr site, Twitter, or his website.
This collage of 72 individual radar-generated images of asteroid 2012 DA14 was created using data from NASA's 230-foot (70-meter) Deep Space Network antenna at Goldstone, Calif. Image credit: NASA/JPL-Caltech
The Jet Propulsion Laboratory has released an initial view of radar observations of asteroid 2012 DA14 generated from data obtained by NASA’s Goldstone Solar System Radar, taken on Feb. 15-16, 2013 as the asteroid headed away from Earth. While these first radar data aren’t very picturesque, they do reveal one obvious thing: this asteroid is tumbler.
The movie is comprised of 73 radar “images” looped nine times. JPL said that during the observations, the space rock’s distance increased from 120,000 to 314,000 km (74,000 to 195,000 miles) from Earth. The resolution here is 4 meters per pixel.
The images span close to eight hours and clearly show an elongated object undergoing roughly one full rotation. JPL said the images suggest that the asteroid has a long axis of about 40 meters (130 feet). The radar observations were led by scientists Lance Benner and Marina Brozovic of JPL. Additional Goldstone radar observations were taken as the asteroid continued to move away from Earth, on February 18, 19, with more observations scheduled on the 20th.
Radar is one of the best techniques for studying an asteroid’s size, shape, rotation state, surface features and surface roughness, and for improving calculations of its orbit. Radar measurements of asteroid distances and velocities often enable computation of asteroid orbits much further into the future than if radar observations weren’t available.
Asteroid DA14 seen from the 2.1 Kitt Peak telescope as it departed the vicinity of Earth. Credit: NOAO/Nicholas Moskovitz (MIT)
Just as anticipated, on Friday, Feb. 15, asteroid 2012 DA14 passed us by, zipping 27,000 kilometers (17,000 miles) above Earth’s surface — well within the ring of geostationary weather and communications satellites that ring our world. Traveling a breakneck 28,100 km/hr (that’s nearly five miles a second!) the 50-meter space rock was a fast-moving target for professional and amateur observers alike. And even as it was heading away from Earth DA14 was captured on camera by a team led by MIT researcher Dr. Nicholas Moskovitz using the 2.1-meter telescope at the Kitt Peak National Observatory in Tucson, AZ. The team’s images are shown above as an animated gif (you may need to click the image to play it.)
This object’s close pass, coupled with the completely unexpected appearance of a remarkably large meteor in the skies over Chelyabinsk, Russia on the morning of the same day, highlight the need for continued research of near-Earth objects (NEOs) — since there are plenty more out there where these came from.
“Flybys like this, particularly for objects smaller than 2012 DA14, are not uncommon. This one was special because we knew about it well in advance so that observations could be planned to look at how asteroids are effected by the Earth’s gravity when they come so close.”
– Dr. Nicholas Moskovitz, MIT
The animation shows 2012 DA14 passing inside the Little Dipper, crossing an area about a third the size of the full Moon in 45 minutes. North is to the left.
(For a high-resolution version of the animation, click here.)
Exterior of the 2.1-meter telescope of the Kitt Peak National Observatory (NOAO/AURA/NSF)
According to the National Optical Astronomy Observatory, which operates the Kitt Peak Observatory, Dr. Moskovitz’ NSF-supported team “are analyzing their data to measure any changes in the rotation rate of the asteroid after its close encounter with the Earth. Although asteroids are generally too small to resolve with optical telescopes, their irregular shape causes their brightness to change as they rotate. Measuring the rotation rate of the asteroid in this way allows the team to test models that predict how the earth’s gravity can affect close-passing asteroids. This will lead to a better understanding of whether objects like 2012 DA14 are rubble piles or single solid rocks.
“This is critical to understanding the potential hazards that other asteroids could pose if they collide with the Earth.”
So just how close was DA14’s “close pass?” Well, if Earth were just a few minutes farther along in its orbit, we would likely be looking at images of its impact rather than its departure.*
Although this particular asteroid isn’t expected to approach Earth so closely at any time in the foreseeable future — at least within the next 130 years — there are lots of such Earth-crossing objects within the inner Solar System… some we’re aware of, but many that we’re not. Identifying them and knowing as many details as possible about their orbits, shapes, and compositions is key.
Even this soon after the Feb. 15 flyby observations of 2012 DA14 have provided more information on its orbit and characteristics., allowing for fine-tuning of the data on it.
According to the Goldstone Radar Observatory web page, the details on 2012 DA14 are as follows:
Semimajor axis 1.002 AU
Eccentricity 0.108
Inclination 10.4 deg
Perihelion distance 0.893 AU
Aphelion distance 1.110 AU
Absolute magnitude (H) 24.4
Diameter ~50 meters (+- a factor of two)
Rotation period ~6 h (N. Moskovitz, pers. comm.)
Pole direction unknown
Lightcurve amplitude ~1 mag (N. Moskovitz, pers. comm.)
Spectral class Ld (N. Moskovitz, pers. comm.)
Goldstone is currently conducting radar observations on the asteroid. A radar map of its surface and motion is anticipated in the near future.
A bright daytime meteor witnessed over Russia on Feb. 15, 2013 (RussiaToday)
Also, in an encouraging move by international leaders in the field, during the fiftieth session of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, currently being held from at the United Nation Office in Vienna, near-Earth objects are on the agenda with a final report to be issued by an Action Team. Read the report PDF here.
*According to astronomer Phil Plait, while the orbits of Earth and DA14 might intersect at some point, on the 15th of February 2013 the asteroid slipped just outside of Earth’s orbit — a little over 17,000 miles shy. “It was traveling one way and the Earth another, so they could not have hit each other on this pass no matter where Earth was in its orbit,” he wrote in an email. Still, 17,000 miles is a very close call astronomically, and according to Neil deGrasse Tyson on Twitter, it “will one day hit us, like the one in Russian [sic] last night.” When? We don’t know yet. That’s why we must keep watching.
A portrait of William Shakespeare on the cover of the first Folio of his plays. Credit: Elizabethan Club of Yale University
With all this talk lately of rocks whizzing by Earth (or crashing through the atmosphere), it’s remarkable that we didn’t even know of space rocks a few centuries ago. The first asteroid, 1 Ceres, was discovered in 1801.
Dial back a few centuries, and we were still in the realm of a perfect universe with the Earth at the center. William Shakespeare’s (1564-1616) plays are full of these references. Universe Today recently stumbled across a 1964 Irish Astronomical Journal paper replete with examples.
Shakespeare was born about 20 years after Nicolaus Copernicus, whose book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) laid out the case for the Sun-centered solar system. It took a while for Copernicus’ theories to take hold, however.
While bearing in mind that Shakespeare often wrote about historical personages, one passage from Troilus and Cressida demonstrates an example of the characters speaking of the Sun following the other planets in circles around the Earth.
The heavens themselves, the planets, and this centre,
Observe degree, priority and place.
Insisture, course, proportion, season, form,
Office, and custom, in all line of order:
And therefore is the glorious planet Sol
In noble eminence enthroned and sphered
Amidst the other …
An Earth-centered solar system had its problems when predicting the paths of the planets. Astronomers couldn’t figure out why Mars reversed in its path in the sky, for example.
The real explanation is the Earth “catching up” and passing Mars in its orbit, but astronomers in Shakespeare’s time commonly used “epicycles” (small circles in a planet’s orbit) to explain what was going on. Shakespeare wrote about this problem in Henry VI:
Mars his true moving, even as in the heavens,
So in the earth, to this day is not known.
However, the Bard displayed a more modern understanding of the Moon’s movement around the Earth, the paper points out. The Moon’s distance varies in its orbit, a fact spoken about in Othello, although note that Shakespeare attributes madness to the moon’s movements:
It is the very error of the moon;
She comes more near the earth than she was wont
And makes men mad.
For more examples — including what Shakespeare thought about astrology — you can check out the paper here.
A photo of Asteroid 2012 DA 14 as seen from the suburbs of Paris on February 15, 2013. Credit and copyright: Thierry Legault.
Yesterday a 50 meter (160 foot) rock passed just over 27,000 kilometers (17,000 miles) from the Earth’s surface. This big space rock, named 2012 DA14, dodged us while another smaller and unrelated asteroid gave us an extraterrestrial punch over Russia (read more about that here). Telescopes around the world — both big professional ones and smaller amateur ones — focused on the fast-moving 2012 DA14, whizzing along at 28,100 kilometers per hour (17,450 miles per hour), or 7.82 kilometers per second (4.8 miles per second) relative to Earth.
Here are some of the images from around the world of 2012 DA14. Noted French astrophotographer Thierry Legault sent Universe Today a note that he “easily spotted it visually through the 4″ refractor. It was running very fast amongst the stars!” he said.
In a really nice piece of astrophotography, François Colas from the Pic du Midi observatory in southern France captured the fast moving asteroid with just the right combination of exposure, allowing him to get the asteroid as a point and not a line. He used a Pentax K5 – 6400 ASA – 85mm f/1.4. Field of view 15°
Richard Fleet from Wiltshire, England also got a good capture of the asteroid. “Clouds were a problem most of the evening but I did manage to catch it going past the Coma Berenices cluster,” he said via email. “I saw the asteroid several times in 15×75 binoculars and the motion was obvious in seconds when it was near a star, though it took a bit longer to be sure in the more barren areas.”
He used a used a 200mm lens on a Canon 5D for the very nice sequence as it ‘ran among the stars’:
Image taken remotely from Spain on February 15, 2013 at 22:31UT, 3 hours after the close approach. Credit: Ernesto Guido and Nick Howes/Remanzacco Observatory.
The Remanzacco Observatory team has been following 2012 DA14 for a few days (click on the image above for their animation if it not ‘animating’.) See their website for several different shots from various remote telescopes around the world.
This image shows asteroid 2012 DA14 and the Eta Carinae Nebula, with the white box highlighting the asteroid’s path. The image was taken using a 3″ refractor equipped with a color CCD camera. The telescope is located at the Siding Spring Observatory in Australia and is maintained and owned by iTelescope.net. Credit: Aaron Kingery/NASA/MSFC
Gianluca Masi from the Virtual Telescope Project held a special webcast for the close approach of this asteroid. He reported they had more than 150,000 viewers from 166 countries. “Unfortunately, the clouds came, too, but at least we had some clear skies soon after the minimum distance was [reached],” he wrote. “For the occasion, the PlaneWave 17? robotic unit was used, trusting its exceptional Paramount ME robotic mount. The mount was controlled by TheSkyX Pro suite and the software was perfectly tuned to track this VERY DIFFICULT target. The results shown here speak by themselves: the asteroid was perfectly tracked, despite it was moving at 0.65 degrees per minute! All this after the scope was just slewed, without any manual adjustment! Amazing.”
2012 DA14 was about 36,500 km from Earth at the time.
Animation of 2012 DA14 created from 17 images, each with 3 second of exposures. Credit: Gianluca Masi, Virtual Telescope Project. Click on the image to animate if it is not ‘moving’ in your browser.
The Talmassons astronomy club from Udine, Italy took this imagery:
Shahrin Ahmad from Kuala Lumpur, Malaysia posted some of his images on Google+:
A 30 second exposure of Asteroid 2012 DA14 passing by Theta Crateris on Feb. 15, 2013 at 19:22 UTC, as seen from Malaysia. The Moon is added for comparison.Credit: Shahrin Ahmad
Nahum Mendez Chazarra from Spain’s Centro de Investigación y Divulgación Astronómica del Mediterráneo sent the video below. You can see more images on their Facebook page.
The Bareket Observatory in Israel had a live webcast of 2012 DA14’s close pass, and they reported they had more than 150K viewers overall. Here is a video they put together of some of the highlights of their observations:
Asteroid 2012 DA14 flies by NGC 4244 at a distance of 14 million light years. Credit and copyright: David G. Strange.
Nick Rose from San Mateo, California tracked 2012 DA14 on its way as it headed away from Earth, using a 6″ reflector with a high end Orion CCD imager on a modified Vixen Super Polaris mount, on the evening of February 15. “I inverted the image to make it easier to see the asteroid,” Nick said, “and the video consists of 100 10 second Binned 1×1 images.”
Mikko Suominen, a freelance science journalist from Finland created this 3-D animation based on the JPL’s information graphics using rendering software called Blender. “They ar not extremely precise,” Suominen said via email, “but for popular science purposes I think they are accurate enough.”
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
A meteorite flashes across the sky over Chelyabinsk, Russia, taken from a dashboard camera.
A small asteroid entered Earth’s atmosphere early Friday, February 15, 2013 over Chelyabinsk, Russia at about 9:20 am local Russian time. Initial estimates, according to Bill Cooke, lead for the Meteoroid Environments Office at NASA’s Marshall Space Flight Center, is that the asteroid was about 15 meters (50 feet) in diameter, with a weight of 7,000 metric tons. It hit the atmosphere at a shallow angle of about 20 degrees, at a speed of about 65,000 km/h (40,000 mph).
It traveled through the atmosphere for about 30 seconds before breaking apart and producing violent airburst ‘explosion’ about 20-25 km (12-15 miles) above Earth’s surface, producing an energy shockwave equivalent to a 300 kilotons explosion. That energy propagated down through the atmosphere, stuck the city below – the Chelyabinsk region has a population of about 1 million — and windows were broken, walls collapsed and there were other reports of minor damage throughout the city.
The official impact time was 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).
Cooke said that at this time, the known damage is not due to fragments of the bolide striking the ground but only from the airburst. “There are undoubtedly fragments on the ground, but at the current time no pieces have been recovered that we can verify with any certainty,” Cooke said during a media teleconference today.
He added that the space rock appears to be “an asteroid in nature,” – likely a rocky asteroid since it broke apart in the atmosphere. It wasn’t detected by telescopes searching for asteroids because of its small size, but also because “it came out of the daylight side of our planet – was in the daylight sky and as a result was not detected by any earth based telescopes. #RussianMeteor was not detected from Earth because it came from the daylight side (i.e the Sun-facing side of Earth).
The meteor left a trail in the sky about 480 km (300 miles) long.
Cooke, along with Paul Chodas, a research scientist in the Near Earth Object Program Office at NASA’s Jet Propulsion Laboratory said that asteroids this size hit the Earth on average about once every 100 years. “These are rare events, and it was an incredible coincidence that it happened on the same day as the close flyby of Asteroid 2012 DA14,” Chodas said. “The two are not related in any way.”
The Russian meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia. Oddly enough, the Tunguska event was caused by an object about the size of 2012 DA14, the asteroid that flew by Earth today harmlessly. The meteor, which was about one-third the diameter of asteroid 2012 DA14, became brighter than the Sun, as seen in some of the videos here. Its trail was visible for about 30 seconds, so it was a grazing impact through the atmosphere.
There were certainly pieces that hit the ground, according to Jon M. Friedrich from Fordham University. “For something that created a bolide and sonic detonation of the size seen in Russia, it seems likely that fragments reached the earth,”Friedrich said in an email to Universe Today. “In fact, there are reports of a crater in a frozen lake and other locations that were in the path of the meteor. The resulting fragments are not likely large – I’d expect some of the absolute largest to be football to basketball sized, with many fragments being smaller, like marbles.”
Chodas said that defending the Earth against tiny asteroids like this is challenging issue, “something that is not currently our goal,” he said. “NASA’s goal it to find the larger asteroids. Even 2012 DA14 is on the smaller size. The tiny asteroid that hit over Russia is very difficult to detect, an in order to defend the Earth, the problem and issue there is to find these things early enough to do something about it if we wanted to divert it. While smaller asteroids are easier to divert, they are much more difficult to detect.”
“What an amazing day for near Earth objects,” Chodas said, “with two events happening on the same day.”
The lead animation courtesy of Analytical Graphics, Inc.
