Did you know that Genghis Khan might have decided to move his conquest westwards because of the direction of
Halley's comet? While it might seem silly to think that such monumental decisions may have been taken based on extraterrestrial bodies separated billions of kilometres from us, sometimes it just takes one
celestial event to understand why.
On a serene Saturday evening, the skies over
Spain and
Portugal were set ablaze by a spectacular celestial event that left onlookers in awe. At approximately 11:46 p.m. in Portugal, a
fragment of an unidentified
comet streaked through the atmosphere at a blistering 45 kilometres per second, lighting up the night with a mesmerising flash of blue, green, and white. Momentarily turning night into day, the phenomenon has been captured in numerous social media videos.
Unlike the more common rocky asteroids that frequently burn up in Earth's atmosphere, this weekend's projectile had an unusual trajectory and speed. While earlier termed a “meteor”, experts from the European Space Agency (
ESA) later identified it as a fragment of a comet, an ancient icy body possibly dating back to the dawn of the solar system.
Meteors and comets, while both originating from space, have distinct differences. A meteor is a fragment of a meteoroid or asteroid that burns up upon entering Earth’s atmosphere, creating a bright streak in the sky commonly referred to as a "shooting star." In contrast, comets are icy bodies originating from the outer solar system. When they approach the Sun, the heat vaporises their ice, often forming a tail that points away from the Sun. Comets are typically visible for longer periods than meteors.
“It’s an unexpected interplanetary fireworks show,” astronomer Meg Schwamb tells the media. “This chunk is likely a bit bigger than a good fraction of the meteors we see during meteor showers, so this just made a bigger light show”. According to the ESA, our
blue comet shard met its fiery end 60 kilometres above the Atlantic Ocean, disintegrating entirely before reaching the ground.
Early detection of such objects is key to preventing potential disasters, yet the weekend's comet shard went unnoticed until it disintegrated in the sky. There is an ongoing concern that larger, potentially hazardous objects could similarly escape detection and cause significant damage. The 2013 Chelyabinsk meteor event, which injured over 1,200 people in Russia, serves as a stark reminder of this risk.
To that end, next-generation observatories like Chile’s Vera C. Rubin Observatory is poised to play a crucial role in help in interplanetary defense against such threats.
