If Knowledge is Power, Should we be told about an Asteroid Impact?

I'm a firm believer in the old saying that knowledge is power. But apparently not everyone feels that way and some want to resurrect the old saying that ignorance is bliss. Last Friday, at the annual meeting of the American Association for the Advancement of Science (AAAS,) some people suggested that there was no point in worrying the global population about it's demise. Should we be told if a killer asteroid or comet is on a collision course with Earth?

"If there is absolutely nothing you can do about it - you can't intercept it, you can't move people out of the way - then it makes no sense to incur social costs from whatever panic or overreaction there will be." At least that was the argument from Geoffrey Sommer, of the Rand Corporation, who has been studying how policymakers should react and prepare for Armageddon. "If an extinction-type impact is inevitable, then ignorance for the populous is bliss."

Not everyone feels that way however, and many scientists felt that people have a right to know. There is also a lot of debate on whether we could do something about such a threat. Again, many scientists feel that we could rise to such a challenge.

The first thing you need to know is that it is not a matter of "if" a major impact is a threat, but "when." It is a certainty. We have been hit in the past and we will be hit again. Earth has many scars from impact craters, perhaps the best known in this country is Barringer Crater in Arizona. Every year, a small asteroid explodes in the Earth's atmosphere with an energy equivalent to 5,000 tonnes of TNT. But the geological records show that Earth has suffered major extinctions of life because of celestial impacts. The dinosaurs were wiped out by a collision 65 million years ago. That turned out to be good luck for us mammals however! Some impacts though, have been so massive they threatened to destroy all life on the planet.

All asteroid researchers agree that we will be hit again by objects large enough to cause significant damage, though it may not happen for tens, hundreds or thousands of years. The Spaceguard Survey, conducted by the Nasa, is looking for these big rocks with wide-field telescopes. So far, searching space out to about 200 million km, Spaceguard has found about 650 large asteroids, none of which pose a threat to Earth. Once the objects are identified, their orbits are computed so they can be tracked.

There are undoubtedly many undiscovered rocks out in the same region that have yet to be tracked down however. If a threatening object is found, many researchers are confident Earth will have the time and the technology to do something about it. We have already landed a spacecraft on an asteroid. We possess thruster devices which could be used to change the orbit of the asteroid.

There is however, a more sinister, yet beautiful, object out there which could pose a far more dangerous threat. Most comets come from the dark outback of the Solar System. Most people think of comets as those graceful visitors with the classic tail streaming out behind it. But comets don't get that tail until they get quite close to the Sun. Before that, they are a dark icy rock that is hard to spot. We often do not see comets until they are inside of Jupiter's orbit and by then, it would give us a very short time to do something about it if it was on a collision course with Earth.

By the end of the meeting, just about everyone agreed that proper disaster plans must be put in place to deal with impact threats, and that the public needs to be educated about such a threat, and how we might cope with it.

Constellations

The Solar System