In January 2018, a falling meteorite created a bright fireball that formed an arc over the outskirts of Detroit, Michigan, followed by loud sonic booms.
The visitor not only threw many meteorites onto the snowy earth, but also provided information about his extraterrestrial source.
Although tens of thousands of meteorites were discovered by humans, scientists were able to track only a small number of orbits. Most of them have been calculated in the last decade.
Scientists can use information about how a meteorite burned out in the Earth’s atmosphere to calculate how a rocky object moved in space before it turned into a ball of fire.
Researchers cannot trace a specific path of an object in time - too many variables can affect its movement. But they can determine the most likely ways. Studying the probable orbits of such asteroids can help identify their parent body, the larger asteroid of which they were once a part.
“This is a great way to do what is a low-cost mission to return an asteroid sample,” says Dr. Peter Brown, who studies asteroids at Canadian University of Western Ontario. “In this case, the sample comes to us. We do not need to go to the model. "
Dr. Brown and his colleagues have gathered information from fireball surveys, as well as videos posted on social networks, to restore a potential orbit for the Hamburg meteorite, named after a small suburb of Detroit.
The team then worked with several amateur photographers to calibrate their observations. “We spent a lot of time watching YouTube and Twitter,” he says.
Researchers found that the Hamburg meteorite was a fairly typical fireball. He probably got into the atmosphere with a mass of 60 to 220 kg and a diameter of 0.3 to 0.5 m.
Moving at a speed of about 16 km / s, he produced two large flares at 24.1 km and 21.7 km above the ground. The total energy produced by the fireball was anywhere from two to seven tons of TNT.
While some researchers took to the ground to hunt for dark meteorites in Michigan's snow, Dr. Brown and his colleagues went online to find reports of the fall. Dr. Brown said that since the region was densely populated, there were many videos showing the fall.
Of the many surveillance cameras and CCTV cameras, they found almost 30 unique videos that were sharp enough to show their whereabouts. Of these, only a handful was good enough for team members to perform a detailed calibration.
How do you calibrate a random fireball video? First, you need to have a positional link that helps you pinpoint where the video came from. Ideally, the same camera should be located exactly where the meteorite was originally observed, although a similar camera was often used instead.
The measurements from these videos showed the angle at which the incoming meteorite passed. “Most of the work was just with people,” says Dr. Brown.
In addition to random images, the researchers looked at images from studies of the fireball, where calibration had already been performed.
Although official data was easier to work with, Dr. Brown says smartphones and dashboard cameras often have higher resolution, providing more accurate data if they can be calibrated. According to him, the growing prevalence of such cameras "has almost revolutionized this area."
Although humans have been collecting meteorites for millennia, it was only in 1959 that the first meteor orbit was discovered. Cameras controlled by the Ondrejov Observatory in the Czech Republic recorded a fall of the Pribram meteorite, which allowed researchers to trace its orbit to the asteroid belt.
For the first time, astronomers were sure that meteors came from asteroids. “This orbit really sealed it,” says Dr. Brown.
Fireball networks appeared on the net in the 1960s, 70s and 80s, and by 2000 four meteor orbits were known. Three of them were H-chondrites, the iron-rich meteorite class that most often falls, and the group to which Hamburg belongs.
Since 2000, the number of meteorites with orbits that can be calculated has increased. According to Dr. Brown, 10 more were discovered by 2010. Over the past few years, several tracked meteorites have been produced annually.
Today, there are about 30 meteorites whose orbits were calculated. While the proliferation of cameras designed to track fireballs has played an important role, Dr. Brown says random recordings have also advanced.
According to Dr. Brown, the fall in Hamburg "was very well recorded, and that makes it so interesting." After the more powerful Chelyabinsk fireball of 2013, "there is no other fall that would have so many videos."
The visitor not only threw many meteorites onto the snowy earth, but also provided information about his extraterrestrial source.
Although tens of thousands of meteorites were discovered by humans, scientists were able to track only a small number of orbits. Most of them have been calculated in the last decade.
Scientists can use information about how a meteorite burned out in the Earth’s atmosphere to calculate how a rocky object moved in space before it turned into a ball of fire.
Researchers cannot trace a specific path of an object in time - too many variables can affect its movement. But they can determine the most likely ways. Studying the probable orbits of such asteroids can help identify their parent body, the larger asteroid of which they were once a part.
“This is a great way to do what is a low-cost mission to return an asteroid sample,” says Dr. Peter Brown, who studies asteroids at Canadian University of Western Ontario. “In this case, the sample comes to us. We do not need to go to the model. "
Dr. Brown and his colleagues have gathered information from fireball surveys, as well as videos posted on social networks, to restore a potential orbit for the Hamburg meteorite, named after a small suburb of Detroit.
The team then worked with several amateur photographers to calibrate their observations. “We spent a lot of time watching YouTube and Twitter,” he says.
Researchers found that the Hamburg meteorite was a fairly typical fireball. He probably got into the atmosphere with a mass of 60 to 220 kg and a diameter of 0.3 to 0.5 m.
Moving at a speed of about 16 km / s, he produced two large flares at 24.1 km and 21.7 km above the ground. The total energy produced by the fireball was anywhere from two to seven tons of TNT.
While some researchers took to the ground to hunt for dark meteorites in Michigan's snow, Dr. Brown and his colleagues went online to find reports of the fall. Dr. Brown said that since the region was densely populated, there were many videos showing the fall.
Of the many surveillance cameras and CCTV cameras, they found almost 30 unique videos that were sharp enough to show their whereabouts. Of these, only a handful was good enough for team members to perform a detailed calibration.
How do you calibrate a random fireball video? First, you need to have a positional link that helps you pinpoint where the video came from. Ideally, the same camera should be located exactly where the meteorite was originally observed, although a similar camera was often used instead.
The measurements from these videos showed the angle at which the incoming meteorite passed. “Most of the work was just with people,” says Dr. Brown.
In addition to random images, the researchers looked at images from studies of the fireball, where calibration had already been performed.
Although official data was easier to work with, Dr. Brown says smartphones and dashboard cameras often have higher resolution, providing more accurate data if they can be calibrated. According to him, the growing prevalence of such cameras "has almost revolutionized this area."
Although humans have been collecting meteorites for millennia, it was only in 1959 that the first meteor orbit was discovered. Cameras controlled by the Ondrejov Observatory in the Czech Republic recorded a fall of the Pribram meteorite, which allowed researchers to trace its orbit to the asteroid belt.
For the first time, astronomers were sure that meteors came from asteroids. “This orbit really sealed it,” says Dr. Brown.
Fireball networks appeared on the net in the 1960s, 70s and 80s, and by 2000 four meteor orbits were known. Three of them were H-chondrites, the iron-rich meteorite class that most often falls, and the group to which Hamburg belongs.
Since 2000, the number of meteorites with orbits that can be calculated has increased. According to Dr. Brown, 10 more were discovered by 2010. Over the past few years, several tracked meteorites have been produced annually.
Today, there are about 30 meteorites whose orbits were calculated. While the proliferation of cameras designed to track fireballs has played an important role, Dr. Brown says random recordings have also advanced.
According to Dr. Brown, the fall in Hamburg "was very well recorded, and that makes it so interesting." After the more powerful Chelyabinsk fireball of 2013, "there is no other fall that would have so many videos."
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