Thu. Jun 27th, 2019

Amazing Images Capture Giant Fireball Exploding Over the Bering Sea

3 min read

A powerful fireball exploded over the wilds of eastern Russia last December. Satellites captured the whole thing. 

In this animated sequence of photos taken by Japan’s Himawari 8 weather satellite on Dec. 18, 2018, you can follow the progress of the dark dust cloud and glowing trail left by the meteoroid as it came crashing down into Earth’s atmosphere at an estimated 32 km/s (72,000 mph).
Japan Meteorological Agency

I was probably picking up a last-minute Christmas gift when it happened. Last December 18th at 11:48 a.m. local time, a meteoroid exploded with 10 times the force of the Hiroshima atomic bomb over the Bering Sea. It became the second most powerful meteor blast this century, after the Chelyabinsk explosion in 2013 that released the energy equivalent of 20 to 30 atomic bombs.

Interplanetary encounter

A single frame from Himawari 8 shows the dust trail and a truncated glowing meteor. Photos were taken at intervals, so we don’t get a continuous view. Rocked by its high-speed impact with the atmosphere, the meteoroid exploded about 26 kilometers above Earth’s surface.
Japan Meteorological Agency

Had there been eyewitnesses, we’d have known about the Bering blast within minutes, but it happened beneath the cloud deck in a sparsely populated region off the east coast of Russia’s Kamchatka Peninsula (58.6°N, 174.2°W). Military satellites designed to look for nuclear explosions picked up the blast, as did more than 16 infrasound detectors worldwide. Luckily for us, so did the Japanese Himawari 8 satellite, which took striking images of the sooty trail of dust ablated from the meteoroid during its atmospheric passage. The images also captured the meteor proper — an orange streak of ionized air. If you watch it over and over, you can actually see the dust materialize as the meteoric glow subsides. Rare imagery indeed!

East target Earth

Fireballs and their magnitude as reported by U.S. government sensors.
Alex Chamberlin / JPL-Caltech

Peter Brown, a meteor scientist and planetary astronomer at the University of Western Ontario, first tweeted the news on March 8th. Now it’s making the rounds of the internet in various forms including being falsely reported on a few sites as occurring over Greenland. Based on the imagery and infrasound data, the asteroid responsible for all the fuss measured about 10 meters across, or a little larger than a two-story building. It packed the force of ~176 kilotons of TNT and would have made a spectacular sight. Perhaps ground video may yet surface.

Given the magnitude of the blast it’s very possible that meteorites fell, likely in the Bering Sea. The Cuba meteorite fall on February 1st produced a far less powerful blast — only in the kiloton range — but made a memorable sonic boom and showered the region with many stony meteorites. Significant airbursts like the Kamchatka meteor occur about three to four times a century.

Fireball explosion over Pinar del Rio, Cuba, on February 1st. You can hear the explosion at the 55-second mark.

Astronomers have discovered more than 90% of near-Earth asteroids larger than a kilometer across — the ones that would have serious consequences in the event of a strike. But little ones, like Chelyabinsk or Tunguska? Nearly all are unannounced simply because they’re so tiny, they escape our notice. Fortunately, the atmosphere serves as an excellent defense against objects up to several tens of meters.

Comparing cosmic rock energies

Sizes and blast power of three major blasts. Tunguska in 1908 had the force of 10-15 megatons, nearly 1,000 times more powerful than Chelyabinsk.
CC 1.0 / Wikipedia

You can always check on the most recent significant meteor blasts at NASA’s Fireball and Bolide Data page, which also includes more details on the Bering Sea impact.

We’ve also just learned that NASA’s Earth-observing Terra satellite captured an image of the wispy dust trail. Much of a meteoroid’s mass is shed as dust, some of which ultimately serves as nuclei for the formation of noctilucent clouds, pale blue clouds that glow just above the northern horizon at the end evening twilight in summer. In this way, such dramatic and potentially harmful events confirm Earth’s cosmic connection every single day.

Tail end of a battered asteroid

A beautiful photo of the dust trail left by the ablating meteoroid when heat, pressure, and friction stripped its surface of material during the December 18th fall. The object struck the atmosphere almost vertically.

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