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Should Earth's close encounter trigger asteroid avoidance research?

After yet another narrow encounter with an asteroid the size of an airship earlier this week, do we need to pay more attention to technology that could protect our planet and its inhabitants from these turbo-charged cosmic fireworks?

Asteroid 2005 YU55 - which is 400m in diameter - raced past Earth at 30,000mph on Tuesday, reaching its closest point (only 201,700 miles away) at 23:28 GMT. Scientists claimed that if the asteroid had hit Earth it could have wiped out an entire city or caused a 70ft tsunami had it landed in the ocean.

The asteroid, which was first spotted by Arizona University in 2005, swung between the Earth and the moon, and is said to be the closest asteroid to Earth in 200 years. So, has this near miss been a lucky one?

Scientists and politicians who decide to talk seriously about collisions with asteroids are often regarded as cranks. When former Lib-Dem MP Lembit Opik said we needed to invest in asteroid-avoidance technology in 1999 he was widely dismissed as being a bit of an oddball.

However, there are 374 near-Earth objects (NEOs) on NASA’s radar, all of which have the potential to collide with our planet in the next 100 years.

On average, a 10km diameter asteroid strikes the Earth every 26-30m years, while every hundred years there is a Tunguska class (100m-diameter) asteroid impact. What’s worrying is that the last one, which wiped out the dinosaurs, occurred 65m years ago, so you could say we’re overdue.

Scientists claim they are usually aware several years in advance of any large NEOs heading in our direction and during this period they can take the necessary actions.

Apparently, the trick is to gently nudge the asteroid out of the way instead of the preferred disaster movie approach of attempting to blow it to smithereens, which according to NASA would only add to the problem by creating scores of smaller earth-bound asteroids.

Here in the UK, Researchers at Strathclyde University’s engineering department are looking at a number of methods to keep asteroids at bay should they head our way, and there are some intriguing approaches to the problem.

As you might expect, one of the simplest ways to deflect an asteroid is to use a kinetic impactor, such as a spacecraft. Alternatively, a nuclear blast detonated near the surface could also produce the desired effect by vaporizing part of the surface and nudging it off course with the reaction.

A slightly more obscure approach is to use a space mirror that focuses solar energy onto the surface of the asteroid, as a child would with a magnifying glass and a leaf. The concentrated heat sublimates the surface material and creates jets of gas and dust, which reduce the weight of the asteroid and ultimately cause the asteroid’s path to deviate.

Similarly a drilling machine, or something to that effect, could collect material from the asteroid and catapult it into deep space, thus reducing the weight of the asteroid and causing its path to deviate once again. Another slightly bizarre idea is to use propulsion technology, as seen on spacecraft, to thrust the asteroid off course.

All these ideas are great and could potentially save millions of lives, although as with many technologies, an ability to propel objects rapidly through space could have a worrying flip-side. In his book Pale Blue Dot, celebrated science writer Carl Sagan warned that any method capable of deflecting potential impactors away from Earth could also be used to divert non-threatening objects toward the planet. Indeed, our planet’s history of genocidal political leaders led Sagan to conclude that Earth is at greater risk from a man-made impact than a natural one.


Readers' comments (16)

  • Just do the momentum calcs and consider the recent mistargetting of the last Mars probe! Then think again! Please address the real issues in this world!

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  • Not sure why blowing it to bits doesnt result in all the 'bits' changing course under the efect of gravity curved space as their weight has changed?

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  • Seeing as it is global threat it could do with a global solution. It would be a good project to get Russia, USA and China and ESA all working on. The severity an asteroid hitting the earth is so high that I would expect multiple attempts to knock the asteroid off cause. The regular buzzing of earth would give us a chance to try out the technology. The period of the last 2 major extinctions show that we are over due so we should have some thing planned and ready. We would only get 2 years notice so leaving it until we thought an asteroid was going to hit would be too late. Probably the best thing that could happen would be for a reasonably sized asteroid to hit earth and not wipe every one out for it to be taken seriously.

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  • We need to detect any asteroids as soon as possible, so that we may take countermeasures to nudge them onto another track. Any suggestions to the contrary are from the mumbo-jumbo crowd.
    To this end, we need to upgrade our deep space search capability to give us the maximum time. The closer they get, the harder it is to deflect them.

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  • There is no doubt that sometime, somewhere, something sizeable will hit. The Siberia impact of 1906 and 1947 (dates correct?) were really narrow escapes.
    However developing the equipment to deflect or destroy comets or asteroids will take too long. By this I mean more than one politicians 5 year term of office. Planetary impact is not a vote catcher.
    So we probably won't see anything soon.

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  • is said to be the closest asteroid to Earth in 200 years .
    According to wiki, asteroid (153814) 2001 WN5 will be slightly closer in 2028.

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  • Are you serious? We can't even agree to produce energy without fossil fuels before we ruin the atmosphere. We don't have the foresight to make sure nuclear reactors have a backup power supply in event of an earthquake/tsunami (I mean 'stuff' happens, shouldn't you plan for that?).

    Besides, I think we could do alright with a few million less people.

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  • Start a new investor scam. Asteroid Futures Inc....."We insure against impacts, and we ensure your survival"

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  • Simply deflecting an object is not enough(?)You then have a large rock
    flying at some random trajectory. The objects out there are by now
    relatively stable, we have swept-up most of the strays. Should our object
    hit the astroid belt it could cause a catastrophic release of
    rocks in all directions.

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  • "On average, a 10km diameter asteroid strikes the Earth every 26-30m years"

    There have been enough of them to calculate an average?

    Who did the stats?

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  • Editor's note: the Earth is 4.5billion years old. That's old enough for more than 100,000 10km-wide asteroid impacts.

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