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Weather Satellites Captured Chelyabinsk Meteor Data

October 23, 2013
Image Credit: Migel / Shutterstock.com

Lawrence LeBlond for redOrbit.com – Your Universe Online

Environmental satellites tasked with studying Earth’s weather accidentally captured data of an extraterrestrial kind this past February. Scientists studying the Chelyabinsk meteor that blazed a trail over Russia’s Ural Mountains on February 15, 2013 have been able to track the trajectory of the fireball using these weather satellites.

Publishing their work in the Proceedings of the National Academy of Sciences (PNAS), study first author Steven Miller, an atmospheric scientists at Colorado State University, and colleagues suggest that dozens of orbiting and geostationary satellites could be drafted to hunt down and track dangerous near-Earth objects (NEOs).

“Sometimes we can use these Earth-viewing meteorological satellites in unconventional ways,” Miller explained to National Geographic’s Ker Than in an interview. “In this case, we used the debris trail left in the atmosphere by a large meteor to infer the direction from which it came and provide some insight on where it came from.”

Miller, who was home watching TV when news footage of the Chelyabinsk meteor event began streaking across news sites. He said he had to “rewind and play it back a few times” to confirm that what he witnessed was in fact what he was thinking.

The meteor broke through the atmosphere about 9:20 a.m. as it raced toward Russia’s Ural Mountains at blistering speeds approaching 40,000 mph. The 56-foot-wide, nearly 10,000-ton fireball then exploded in the stratosphere over Chelyabinsk with the energy of up to 500 kilotons of TNT, which is about the equivalent of a modern day nuclear bomb. The explosion sent out a shockwave so thunderous that it shattered thousands of windows in the region, injuring at least 1,500 people.

Miller explained that the meteor, which was about the size of a small house, was the largest known object to enter Earth’s atmosphere since the 1908 Tunguska event, which flattened a wide area of forest in Siberia. It is commonly held that a meteor or asteroid was the culprit in that century-ago explosion.

MODERN TECHNOLOGY

As for the 2013 Chelyabinsk event, modern technology helped aid scientists’ ability in better understanding how meteors and other objects act as they enter Earth’s atmosphere.

Numerous dashboard and security cameras managed to catch at least part of the meteor’s path as it hurled its way to its fiery death. But even though these cams provided a pretty good image as to how the meteor behaved, the current study relied on satellite imagery to get the full picture.

The Chelyabinsk meteor was tracked by European, Chinese, Korean and Japanese weather satellites. From the data, scientists were able to predict the meteor’s speed, angle of entry and trajectory through the atmosphere. They also found that their results closely match similar estimates based on high-res photos taken at ground level.

The Earth-viewing satellites captured a “distinctive trail of dust, smoke and ice debris.” “The satellite imagery captures the debris trail left in the wake of the object’s traverse, and we can use details of the trail’s location to infer trajectory of travel through the atmosphere,” the study authors wrote. The authors said that using satellites to track NEOs could be a very important tool in trying to predict when and where a dangerous asteroid may hit Earth.

While it would be thrilling to find one satellite catching such an event, scientists were extremely jubilant in discovering that at least seven geostationary satellites caught the meteor’s dramatic entry and its eventual breakup moments later.

The satellites involved are all situated above the equator at altitudes that allow for speed that matches the Earth’s rotation, allowing them to hover in place.

Scientists also discovered that a defense weather satellite that had just happened to be crossing over the region had captured the event as well, providing a much closer view of the meteor trail.

The meteor and its trail were captured from several different vantage points and using a variety of satellites sensors, including visible and infrared light. The data pulled from the multiple satellites allowed scientists to put together key details about the meteor.

The new findings suggest that satellites could provide a useful means of recording similar events, including those that occur in remote, sparsely populated areas, where ground observations may not exist, said the authors.

DUAL THREATS

Calculating the precise trajectory of such meteors can help reveal important details about its orbit and its source, which could help researchers predict future threats more accurately.

Nick Collins of The Telegraph wrote that around “15 percent of the estimated 1,000 to 2,000 asteroids near Earth are thought to be accompanied by partners orbiting the same centre of mass – meaning the arrival of one could signal a “follow-up threat” from another.”

In fact, just hours after that meteor blazed across the morning sky, exploding over Russia, a much larger asteroid made its closest approach to Earth, screaming by at just 16,800 miles above the planet. While 16,000 miles may seem like a relatively safe distance, in astronomical terms, that is considered missing us by a hair.

However, experts were quick to point out that the Chelyabinsk meteor and the close passing of Asteroid 2012 DA14 on February 15 were two uniquely distinct and separate events and were not associated with one another in any way.

Still, the message here is that satellites could be significant tools in predicting such threats, be it single meteor strikes, or partner threats.

“If used in synergy with other warning and decision aid systems, including resources designed for this purpose,” the researchers wrote, “those satellites could play a complementary role in more rapidly directing our attention and response with regard to possible follow-up threats.”

But in the event of a remote encounter, such as one that cannot be tracked from the ground, “the global constellation of Earth-viewing satellites is far more likely to be in a position to assess trajectory and infer the source.”

Miller said, “If a Chelyabinsk-like event was indeed a harbinger of a series of objects sharing a similar orbit, then perhaps by noting its exact direction of travel there would be an opportunity to focus attention on that specific direction and see if other—and potentially larger—objects are coming.”

Josep Trigo-Rodriguez, head of the Meteorite and Minor Body Planetary Sciences Group at the Institute of Space Sciences (CSIC-IEEC) in Barcelona, Spain, said that even just a few hours warning could be enough time to alert people to seek shelter and avoid the worst effects of a potential impactor.

“For larger bodies it would be better to have several days [lead time] to promote an ordered evacuation,” Trigo-Rodriguez told Than at NatGeo.

DRAWBACKS

While scientists believe satellites could be an extremely useful tool in tracking potential meteors, they do admit the current line of weather and environmental satellites do have drawbacks. As an example, most of these satellites are only designed to study weather effects and their sensors are generally aimed at the Earth and not configured to provide rapid response to such events.

Miller said that in order to best tackle this problem, we should place a “dedicated space telescope for tracking smaller objects in orbit so it can see what’s coming and not what has already entered the atmosphere.”

The Chelyabinsk meteor was tracked by European, Chinese, Korean and Japanese weather satellites. From the data, scientists were able to predict the meteor’s speed, angle of entry and trajectory through the atmosphere. They also found that their results closely match similar estimates based on high-res photos taken at ground level.


Source: Lawrence LeBlond for redOrbit.com - Your Universe Online



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