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Mystery still surrounds 1908 Tunguska event

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Author Topic: Mystery still surrounds 1908 Tunguska event  (Read 113 times)
Teri Charboneau
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« on: July 12, 2016, 01:54:28 am »

The main problem, he says, is that researchers had spent too much time looking for large pieces of rock. "What was necessary was to look for very small particles," such as the ones his team studied.

But it is not a definitive conclusion. Meteor showers occur often. Many small ones might therefore sprinkle their remnants onto Earth unnoticed. Samples with meteoric origin could presumably come from one of these. Some researchers also cast doubt that the peat collected dates from 1908.

Even Artemieva says she needs to revise her models to understand the total absence of meteorites at Tunguska.

Still, in line with Leonid Kulik's early observations, today the broad consensus remains that the Tunguska event was caused by a large cosmic body, like an asteroid or comet, colliding with Earth's atmosphere.

 

Most asteroids have quite stable orbits, many of which are found in the asteroid belt between Mars and Jupiter. However, "various gravitational interactions can make them change their orbit more dramatically," says Gareth Collins of Imperial College London, UK.

Occasionally these rocky bodies can cross over into Earth's orbit which can put them onto a collision course with us. At the point one enters into our atmosphere and begins to fragment, it is known as a meteor.

What made the Tunguska event so dramatic was that it was an extremely rare case of what researchers call a "megaton" event – as the energy emitted was about 10-15 megatons of TNT, though even higher estimates have also been proposed.

This is also why the Tunguska event has been difficult to make full sense of. It is the only event of that magnitude that has happened in recent history. "That limits our understanding," says Collins.

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