Spectacular ’meteor shower’ over SA was actually a ’bolide’
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Cape Town – If a small asteroid or large meteoroid survives its fiery passage through the Earth's atmosphere and lands on its surface, it is then called a meteorite, scientists say.
But what many South Africans thought was a spectacular meteor shower early on Tuesday evening was actually a “bolide”, a very bright meteor that often explodes on entry into the Earth’s atmosphere and can be seen over a wide expanse. It comprises 1 to 10-metre rocks of around 1 648°C and can also be called a fireball.
Dr Daniel Cunnama, science engagement astronomer at the SA Astronomical Observatory, said: ’’A bolide is a single meteor breaking up on entry. A bolide is a very bright meteor.
☄️BREAKING: SA Astronomical Observatory confirms large #meteor/fireball (📸 below) @ 18:21 on Tuesday— Gauteng Weather (@tWeatherSA) August 25, 2021
📍VISIBILITY: GP, LP, NW, MP,🇧🇼&🇿🇼
🪨COMPOSITION: 1-10 metre rocks of around 1,648°C, which explode on entry into atmosphere
Meteorite: Hits ground pic.twitter.com/pRgww9tJfX
’’We expect probably 10s of them per year, but we can’t predict when or where. They are from rocks of 1-10m across entering our atmosphere and breaking up.”
Phys.org explained that bolides can cause shock waves, with a meteor that exploded over Russia in 2013 shattering windows with its air blast.
’’Space debris smaller than an asteroid are called meteoroids. A meteoroid is a piece of interplanetary matter that is smaller than an asteroid and frequently are only millimetres in size,’’ the website stated.
’’Most meteoroids that enter the Earth's atmosphere are so small that they vaporize completely and never reach the planet's surface. When they burn up during their descent, they create a beautiful trail of light known as a meteor, sometimes called a shooting star.
’’Mostly these are harmless, but larger meteors that explode in the atmosphere – sometimes called bolides—can create shock waves, which can cause problems.
’’In February 2013 a meteor that exploded over Chelyabinsk, Russia shattered windows with its air blast. This meteoroid or bolide was estimated to be 18 metres in diameter.’’
On social media, many South Africans, captivated by the experience, shared their videos and photos.
One Twitter user said: ’’So whatever appeared in the sky (my amazing son spotted it, I caught a glimpse thanks to him!) moved north from JHB, centurion, PTA, and ... is it the same thing that crashed in Bulawayo like two minutes later? Is that even possible?’’
Here are some other responses:
Oh my word. Who saw the meteor? (Scenes from that American disaster movie, Greenland, flashing through my mind.) https://t.co/DbDKggtl2e— Jana Marx (@janamarxbalden) August 24, 2021