It's been nearly a month since a fireball lit up the crisp blue skies over Ural Russia as an unusually large meteor plunged to earth, creating a shockwave that blew out windows and injured more than 1,200 people.
The event seared its way into the national consciousness and drew comparisons to the biggest meteor impact ever recorded, the so-called Tunguska event over Siberia more than a century ago.
It also mobilized Russia's and other scientific communities, and sparked a public and private rush to cash in on the passing fame that this rare event offered.
But this week it buttressed Russia's determination that humankind should be more agressively pursuing ways to prevent the kind of catastrophic collision that many think wiped out the dinosaurs 65 million years ago.
Speaking to a special session of the upper house of the Russian parliament, the Federation Council, officials from that country's space agency, nuclear agency, and astronomical institute pressed their case for billions of dollars of investment to prepare for what could eventually be nuclear strikes to deflect or take out approaching comets or asteroids.
They cited the Apophis asteroid's projected near-miss in 2036 and said concrete measures to monitor and possibly intercept an asteroid could be in place as soon as 2018. (U.S. space agency NASA has said there's nothing to worry about from Apophis.)
"The unexpected appearance of out-of-space objects close to the Earth is not an exception but a typical situation and we may have very little time to make a decision to counteract," Boris Shustov, director of Russian Academy of Sciences Astronomy Institute, chairman of the experts' group for space threats, said, according to Reuters.
The meteor that exploded over Chelyabinsk, Russia on February 15 was thought to have been around 15 meters in diameter before hitting the atmosphere and breaking into many pieces, with its largest chunk most likely plunging into Lake Chebarkul.
Here's a brief video
based on University of Western Ontario data showing the estimated orbit of the Chelyabinsk asteroid and its collision course with Earth:
The tracking and avoidance systems under study or in their early stages so far are generally thought to be aimed at tackling larger fragments. And while the Russian meteor was indeed terrifying to those in its immediate vicinity, the urgency of calls for impact-avoidance systems are tempered by the historical record -- the Chelyabinsk event was the largest reported meteor since Tunguska in 1908.
Still, the Russian scientists embraced apocalyptic language in their briefing for lawmakers.
"We will have a very limited amount of time to prevent the collision. About a year, including the launch of an interceptor and separating fragments in space," Oleg Shubin, deputy director for nuclear weapons management at nuclear agency Rosatom said, according to Reuters. "It's also worth mentioning that an interception of a meteorite the size of one kilometer will require the use of nuclear explosive devices with a capacity well exceeding the megaton class."
NASA is already spending money
to develop an Asteroid Terrestrial-Impact Last Alert System (ATLAS), which its backers say could give about a day's warning in cases like that in Chelyabinsk, pinpointing the area of impact within a kilometer or two.
In late February, less than two weeks after the Russian meteor, Canada's space agency launched a microsatellite
as part of its experimental "Sentinel in the Sky," intended to provide an early-warning system for space debris and other near-Earth objects.
Meanwhile, the more immediate work of detailing and categorizing exactly what happened over Chelyabinsk on February 15 has continued.
Aleksei Ischenko, head of lab scanning methods at Ural Federal University's Nanotechnologies and Nanomaterials center, inspects Chelyabinsk meteorite fragments and data.
Russian researchers and volunteers are still rounding up fragments of the meteorite that exploded over the Urals, with initial tests suggesting the event was unusual in its size but not in its other essentials.
Researchers at Ural Federal University (UrFU) have already collected hundreds of fragments from the area where the meteorites came down, referred to as the "strewing field."
UrFU's Institute of Physics and Technology professor Viktor Grokhovsky, who launched its meteorite expedition, told RFE/RL recently: "Our expedition has made three visits to the site and found over 300 fragments, from 3 millimeters to 150 millimeters. There have been several thousand fragments found mostly by the local residents. The ones that could have reached the ground can be up to half meter long."
Here's a video
showing some of the fragments in detail in which Grokhovsky describes the largest of the pieces to have been retrieved so far as weighing 1.8 kilograms (click "captions" to see English subtitles):
He and his colleagues say the asteroid was ordinary or common chondrite, the most common makeup of asteroids and material that's "the same age as the Solar System -- approximately 4.5 billion years old." It consists of minerals like olivine, pyroxene, troilite, and kamacite in combinations that aren't found on Earth.
They and others are still searching for the largest of the chunks that plowed into Russian ground that day.
The Chelyabinsk meteor's fiery mid-morning arrival was the most closely recorded in history, with uploaded dash-cam and other videos of the remarkable scenes emerging within minutes.
That visual record has allowed specialists like Pavel Spurny, from the "fireball studies" team at the Astronomical Institute of the Czech Academy of Sciences at Ondrejov Observatory, to plot in great detail the final airborne seconds of the Chelyabinsk meteor. The goal is to help reconstruct the initial object and its speed, as well as to determine its composition, what parts of it survived, and where those pieces might lie.
Using videos calibrated with Google Maps tools, the Czechs tracked the four largest fragments that in turn disintegrated into thousands of smaller meteorites.
Their preliminary findings were published in a letter to the International Astronomical Union's Central Bureau for Astronomical Telegrams.
They concluded on the basis of video evidence that the Chelyabinsk meteor first appeared at an altitude of around 92 kilometers and streaked for 11 seconds before blowing up as a result of friction and heating around 32 kilometers above ground.
A closeup of a fragment from the Chelyabinsk (Chebarkul) meteorite provided by Urals Federal University (UrFU)
The original asteroid was "relatively fragile in comparison with other superbolides," or fireball meteorites, Spurny told RFE/RL.
He called it "really a unique historical event" in light of its size and its proximity to a major population center. Spurny compared it to two other landmark meteor events that he'd worked on in the past. The first was the so-called Peekskill Meteor, when a chunk of asteroid streaked across the sky above the eastern United States in October 1991 before slamming into a parked car
. That fireball (or superbolide) was caught by at least 16 video cameras, many of which were recording a high-school football game.
The other was the Moravka meteorite incident
in May 2000, named after the city in northeastern Czech Republic where the fragments fell. The fireball from that 1,000-2,000 kilogram object's impact with the atmosphere and subsequent fall was videotaped by at least three people.
The Czech scientists say the biggest of the Chelyabinsk pieces weighs between 200 and 500 kilograms. Asked whether they think that chunk lies below shallow Lake Chebarkul, where a 6-meter-wide round hole was blown in the surface ice, Spurny responded unequivocally: "Certainly. It's directly below the hole." He added that it's likely to have come to rest "tens of meters" beneath Lake Chebarkul's 10 meters of water and 10 meters more of mud.
The prospect of finding that or other chunks of otherworldly matter has meanwhile sparked an old-time meteorite rush in the Urals region, with residents joining the hunt in the frozen countryside for science, profit, or simply a space "memento."
The BBC joined some of those forays into the Chelyabinsk countryside for a report
two weeks after the meteor fall:
The BBC team found four tiny stones within five minutes. Most of those fragments found near Deputatsky are pea-sized, but some can be much bigger -- more like golf balls.
The biggest fragment we saw weighed about 100 grams. It was found by a citizen of Chelyabinsk, who said he had received several offers from friends in Moscow.
"It's like hunting or fishing," said one meteorite hunter. "When you see an animal, your heart starts to beat fast, and when you're fishing -- it's like pulling the fishing rod and thinking there's something extraordinary. This is the same - -you see a tiny hole, try it, and here it is."
There are at least 50 offers on eBay
of purported meteorites from Chelyabinsk/Chebarkul for initial bids as low as $0.99 and up to $1,180, although most are at the low end of the spectrum. The offers are from vendors as farflung as Portugal, Yugoslavia, Germany, Finland, Latvia, and, of course, Russia. The BBC has cited other online offers ranging from around $30 to 11,000 British pounds
($16,650), and "The Daily Telegraph" quoted Chinese experts warning of bogus "meteor fragment" offers on web seller Taobao and in other places in connection with a 10,000-pound pitch
-- Andy Heil