National / Science & Health

Mysterious green fireball observed in skies above Japan on Halloween likely a meteor

by Daisuke Kikuchi

Staff Writer

A mysterious green fireball filmed flying over parts of eastern Japan in the early hours of Monday have left many people wondering what it actually was.

One Twitter user assumed it was an extraterrestrial visitor after the object was seen around 5:30 a.m. Monday, while another joked it was a plasma fireball launched by Gamera, a giant monster from a popular special effects sci-fi film series of the same era and type as Godzilla.

Disappointing as it may be, Hitoshi Yamaoka, a public relations chief at the National Astronomical Observatory of Japan in Tokyo, told The Japan Times that the Halloween mystery was most likely a bolide, or an extremely bright meteor that explodes in the atmosphere, a phenomenon that is not unusual.

“It is not likely a part of a rocket because it went flying from east to west, which is the opposite of the Earth’s rotation. We are assuming that a celestial object that revolves around the sun, such as an asteroid, coincidentally came near the Earth and burned up after entering the atmosphere,” said Yamaoka.

Yamaoka also said that a bolide can be seen in many different colors, and that the green one seen this time is relatively common.

“The color of bolides depends on the components of the atmosphere, such as oxygen, and of the meteor. Green is one of the most common colors,” he said.

On Oct. 31 last year, similar green fireballs were seen in the skies above Poland, which the country’s researchers concluded were part of a Taurid meteor shower. Due to their occurrence, from late October to early November, they are also called Halloween fireballs.

However, Yamaoka said the fireball seen in Japan this time was not likely a Taurid meteor, as this kind of meteor shower moves from west to east in the early mornings.

The bolide was reportedly seen Monday morning in many prefectures including Niigata, Kanagawa, Chiba, Akita and Iwate, but apparently no object made it down to the Earth’s surface.

Regarding the number of people who reported seeing the event, Yamaoka said: “Bolides are reportedly seen once or twice every month in Japan. This time, it was noted at dawn, when people were starting their daily activities, and since it likely passed over some densely populated areas, more people than normal saw it.”

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