Collision course

Collision course

Meteors

A 20 million ton asteroid is currently hurtling through space at 23,000 miles per hour, on a collision course with Earth. But fear not – Nasa has 25 years to stop it.

An illustration of asteroid Apophis nearing Earth. NASA officials insist that, contrary to the dire fears of Russian scientists, Apophis will not hit our planet in 2036.



When Paul Chodas and Steve Chesley arrived at Nasa’s Jet Propulsion Laboratory, in a valley beneath the slopes of California’s San Gabriel Mountains, on October 6 2008, they assumed it would be a normal day. But it would prove to be anything but.

The scientists worked for the space administration’s Near Earth Object (NEO) programme, a team tasked with identifying comets, asteroids and meteors that potentially pose a threat to Earth. A normal day meant scanning their screens for small white dots in our solar system — the vast majority of which were either too far away to ever be a problem or so small they would burn up in our atmosphere long before they could ever do any serious damage. On that Monday morning, however, Chodas noticed an asteroid about the size of a truck beyond the moon’s orbit. It was on a collision course with Earth.

He called Chesley over. The pair estimated the asteroid to be about 5m (16ft) long and they reckoned they had about 19 hours before it hit.

Chesley began punching co-ordinates into his machine, trying to compute exactly where it would make contact. “We have software that computes the trajectories and we can run it right through to impact. I pulled out my National Geographic atlas and Steve went on Google to look it up. We both reached the same conclusion: it was going to hit Sudan in the early hours of the following morning, so our next task was to tell Nasa headquarters.” Although there had never been a precedent (this was the first time in human history that Man had been able to foretell an asteroid’s imminent impact with Earth), there were still procedures in place: if Nasa research scientists working on the NEO programme spotted an asteroid that looked like it could come within six Earth radii (about 23,750 miles), they were to notify Nasa’s head office in Washington DC.



“From there, it certainly went to the State Department,” Chodas says. “I don’t know all the details, but I’ve heard that it went all the way up to the White House.” Chodas and Chesley worked out the asteroid was heading for the middle of the Nubian Desert. “We knew it was small and we were certain most of it would break up in the Earth’s atmosphere so it didn’t pose a hazard – it would be no more than a shower of rocks on the ground. The closest habitation was something called Station Six, an oil-compressing station with a population of about 10,” Chodas says. “It was basically barren desert.”

meteorite

Just before eight in the evening California time and seven in the morning in Sudan, the captain of a KLM flight some 860 miles south-west of Station Six and 30,000ft up in the air saw a flash in the sky. The asteroid, named 2008 TC3, had just entered the Earth’s atmosphere, and one of the 10 people living at Station Six managed to capture a brief image on their mobile phone of the long trail of smoke as the remnants of the near-Earth object plunged into the sand.



Disaster was averted. That time. However, there are plenty more where 2008 TC3 came from and, unfortunately, they are much, much bigger. Earlier this year, news networks around the world warned of a “doomsday asteroid”. Dubbed the “continent killer”, Apophis is a frightening-looking, 250m (820ft)-wide, 20million-ton chunk of rock, ice and dust, pockmarked with craters, which apparently could “land” on Earth, at about 23,000 miles per hour, in 25 years’ time — i.e. in most of our lifetimes.

There are two scenarios: the first, and thankfully most likely, is that Apophis will fly by in April 2029, the year it is due to make its first “close approach”, and that’s the last we’ll see or hear of it. The second is that during that approach, it’ll pass through what scientists refer to as a “keyhole” – a small area of space that can alter the asteroid’s course due to Earth’s gravity. If this happens, it’ll be on a massive collision course with us seven years later, likely to be April 13 2036 — Easter Sunday.

read more: telegraph

Nasa’s Jet Propulsion Laboratory

By |2016-08-09T14:07:00+03:00Oct 31, 2011|Categories: Astronomy|Tags: , , , , |

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