NASA has already begun preparations for the arrival of asteroid 99942 Apophis - dubbed the 'God of Chaos' asteroid - which will skim past the earth in 10 years. The asteroid measures 340 meters across and will pass within just 19,000 miles of Earth's surface. Apophis is one of the largest asteroids to pass so close to the Earth's surface and a collision with the planet has the potential to be devastating for all life on Earth.
[...] The asteroid is set to get closer to the earth than communication and weather satellites in orbit. Most satellites in Earth's orbit are geostationary orbit 36,000 km away (22,236 miles) from the planet.
Apophis is travelling at almost 25,000 mph meaning a slight detour from its trajectory could be catastrophic.
Apophis' size and proximity to Earth have resulted in it being categorised as a Potentially Hazardous Asteroid (PHA) and NASA is keen to learn as much from the asteroid as possible to help prevent further asteroid issues in the future.
NASA scientist are aware that as the asteroid flies by the planet in 2029, its orbit trajectory may also change thus raising fears that in the future the massive rock could collide with the planet.
[...] According to some researchers, the immense size of the rock is not a cause for concern as there is a 1 to 100,000 chance of the asteroid striking the earth.
[...] Astronomer Davide Farnocchia added: "We already know that the close encounter with Earth will change Apophis' orbit.
"But our models also show the close approach could change the way this asteroid spins and it is possible that there will be some surfaces changes, like small avalanches."
See also
(Score: 2) by takyon on Wednesday August 21 2019, @12:06AM (6 children)
Even if 99% of the chunks hit Earth, they would have more surface area and experience more friction in the atmosphere.
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(Score: 0) by Anonymous Coward on Wednesday August 21 2019, @12:19AM (1 child)
Then they would disintegrate into radioactive dust?
(Score: 2) by takyon on Wednesday August 21 2019, @12:24AM
Whatever would happen, it would be a better outcome than a direct hit.
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(Score: 0) by Anonymous Coward on Wednesday August 21 2019, @01:55AM (3 children)
That doesn't lessen the destruction that much. If it hits the ground you get tidal waves and secondary ejecta impacts, but the ground blast is localized and the actual air blast* is lost in the impact explosion.
If you broke it up so much that all the energy was dissipated in the atmosphere you would get a radiant heat burst that would set entire continents on fire, and an air blast that would circle the planet flattening everything.
*air blast - the damage caused by an object coming down through the atmosphere at ridiculous speeds.
(Score: 2) by takyon on Wednesday August 21 2019, @04:28AM (2 children)
That's only 24 Tsar Bombas, and not released all in one instant, starting from the extreme upper atmosphere, and possibly spread out if there are chunks. Doesn't sound so bad unless you are unlucky.
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(Score: 0) by Anonymous Coward on Wednesday August 21 2019, @07:26AM
It might be the same energy as 24 tsar bombas but the destruction would be a lot worse. Nukes waste a lot of destructive potential in overkilling a small area at ground zero. A significant portion is also radiated upwards.
The supposition was that it was broken up enough to not make it to ground. That would mean a downward directed blast over a huge area.
https://en.wikipedia.org/wiki/Chelyabinsk_meteor [wikipedia.org] - estimated at 10 thousand tons.
99942 Apophis is estimated at 61 million tons. If you break it up that's 6,100 simultaneous Chelyabinsk blasts.
(Score: 0) by Anonymous Coward on Wednesday August 21 2019, @04:42PM
Another way of looking at it.
It masses 61,000,000 tons. A cubic km of sea-level air masses about 1,000,000 tons.
Assume conservation of momentum and an impact speed of 10km/s .
For the sake of easy math lets call wind at 220 mph destructive. That's about 100m/s
By the time Apophis has transferred all that momentum to the air 6,100 cubic kilometers of atmosphere are traveling at 100 m/s.
It will also have been heated by the kinetic energy difference between 6.1x10E7 tons at 10km/s and 6.1x10E9 tons at 0.1 km/s which will make it worse.