A weather satellite launched the first time captured images of a big fireball exploding in the Earth's atmosphere on Dec. 18, 2018, according to NASA.
The fireball that blasted over the Bering Sea near the Kamchatka Peninsula in Russia is considered to be the second largest of its kind in 30 years. It is also the biggest since the fireball that exploded in Chelyabinsk in February 2013.
Fireballs are very bright meteors that explode into the Earth's atmosphere.
How Powerful Was It?
The fireball unleashed energy that is equivalent to 173 kilotons of TNT. This is said to be 10 times stronger than the energy released by the "Little Boy" atomic bomb that was dropped in Hiroshima on Aug. 6, 1945.
The energy from the fireball is comparable to 40 percent of the energy released in the Chelyabinsk event.
The historic fireball in Chelyabinsk that radiated 440 kilotons created a staggering shockwave that shattered windows, damaged buildings, and caused 1,200 injuries.
The most powerful fireball explosion observed in modern times was the 1908 Tunguska event that flattened 80 million trees over an area covering more than 772 square miles or about 2,0000 kilometers in Siberia, also in the Russian territory.
Great Ball Of Fire
The massive meteor appeared as a bright orange ball of fire in the sky. Air compression resulting from the speeding of the meteor causes its outer layers to ignite. When too much pressure is released, the rock will eventually shatter into fragments.
Based on the images captured by the Japanese geostationary weather satellite Himawari-8, the ball of fire passed over an area that is not too far from the usual air routes of commercial planes traversing North America and Asia.
This kind of huge near-Earth object is said to be visible on Earth about two or three times in a century. Military satellites of the U.S. Air Force picked up the fireball's explosion and immediately notified NASA.
Although sensors and infrasound detectors worldwide picked up the impact of the powerful blast, the occurrence almost went unnoticed because it obliterated over the sea. It exploded at an estimate of 15 miles above the Earth's atmosphere after descending at a record speed of 20 miles per second.
The meteor trail left an almost vertical, orangy brown trace of smoke against the Earth's cloud layer, an indication that it entered the atmosphere at a very steep trajectory.
"It appears in the images at the right time, it is in the right location, the smoke column is almost vertical, and the smoke is very high. Much higher than any clouds in that region and too high to be a contrail," said Simon Proud, an aviation safety fellow and meteorologist at the University of Oxford, as he described the visual evidence that was taken by Himawari.
Need For Extensive Monitoring
NASA constantly records asteroid and comet fragments entering the Earth's atmosphere on its Near-Earth Object website.
The space agency's Planet Defense Coordination Office is also tracking potentially hazardous objects that come within 5 million miles of the Earth's orbit. In particular, NASA monitors objects that are about 30 meters and can cause significant damage.
NASA is planning to establish a National Near-Earth Object Preparedness Strategy and Action Plan to outline steps to prevent dangerous asteroids from striking Earth.
