Catch A Falling Star

Catch-A-Falling-StarQuestion: On February 6th a meteor burnt up in Earth’s atmosphere and released the equivalent of how much TNT?

Answer: 13,000 tonnes – A meteor carrying 40 times as much energy exploded over Russia in 2013 injuring over 1,000 people

This week we learned that, on 6th February, a meteor burned up in the Earth’s atmosphere 1,000km off the coast of Brazil. The event is listed in NASA’s Near Earth Object Program Report.  Lucky for Brazilians that it did because it carried more energy than half the bombs dropped on London during the Blitz!

Impressive as that sounds, this was by no means the most powerful celestial object to reach our home planet – not even in recent times. Less than 3 years ago a meteor packed with the equivalent of 500,000 tonnes of TNT exploded over Chelyabinsk in Russia.  The resulting shockwave shook buildings and shattered windows.  Luckily no-one was killed but more than 1,000 people were injured.  So, 2 meteor strikes in 3 years and no fatalities – are rocks falling from space really a danger to humanity?

Impacts are very rare. Approximately 30 small asteroids reach Earth every year but they pose little threat.  Only very large ones make it all the way to the surface intact.  The largest visitor in the last 2 centuries exploded above Siberia in 1908. This was

1,000 times more powerful than the nuclear bomb which fell on Hiroshima in WWII.  Thankfully it exploded over an uninhabited and desolate area so there were no casualties.  Still, it flattened 2,000 square km of forest.  Just imagine if it had been over Moscow, Paris or New York.  The death toll would have been colossal.

But even the Siberian meteor was not large enough to reach earth’s surface. Only those 1km or more across could do that.  Thankfully these are extremely rare – but they can and do happen. Asteroid strikes are known to have caused at least 2 major extinction events. The last, and most famous, happened 66 million years ago and wiped out the dinosaurs, along with 75% of all life on Earth. If such an event happened again we would see firestorms which would destroy forests and vegetation, huge tsunamis which would flood coastal areas and drown coastal cities, and a long period of dark and cold caused by dust and debris being thrown into the atmosphere. Photosynthesis would be affected and famine would follow.

All of this is unlikely, but still possible. So what can we do to defend ourselves? Here are some of the options:

  • Nuclear bombs – The energy of a nuclear explosion on or near a threatening asteroid may be enough to change its course away from Earth.
  • Impact – Ramming a near Earth object could knock it off course… maybe.
  • Gravity pull – The gravity of a close space craft might be enough to pull an asteroid off its current trajectory.

These, of course, all presume that we know of the approaching danger well in advance, though most encounters come with no prior warning. There are some other suggestions – such as focusing the Sun’s rays or using magnets and lasers – though these seem in the realm of science-fiction, at least for the time being.

We here at Education Quizzes do not shy away from serious discussions, and neither do we believe that parents should.  Why not discuss the issue with your child? Don’t be too alarmed – the next major event may be millions of years away, but it just might be sooner. Maybe your chat will awaken an interest in science and, who knows – maybe your little one might be the name on the lips of future generations: The Man (or woman) Who Saved The Earth From The Killer Asteroid!

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