EXECUTIVE  SUMMARY

Enormous numbers of asteroids and comets orbit the Sun. Only a tiny fraction of them have paths that bring them close to the Earth. These Near Earth Objects range in size from pebbles to Mountains and travel at high speeds.

Such objects have collided with the Earth since its formation, and brought the water and carbon that made life possible. They have also caused widespread changes in the Earth's surface, and occasionally extinctions of living organisms such as the Dinosaurs. The threat has only recently been recognised and accepted. This has come through advances in telescope technology allowing the study of these usually faint objects, the identification of craters on the Moon, other planets and the Earth as a result of impact, and the dramatic collision of pieces of the comet Shoemaker-Levy 9 with Jupiter in 1994.

Impacts represent a significant threat to human and other forms of life. Means now exist to mitigate the consequences of such impacts for the human species.

The largest uncertainty in risk analysis arises from our incomplete knowledge of asteroids whose orbits

bring them near to the Earth. With greater information about them, fairly accurate predictions can be made. The risk from comets is from 10 to 30 percent of that from asteroids. The advance warning period for the potential impact from a long period comet may be as short as a year compared to decades or centuries for asteroids. Short period comets can be considered along with asteroids.

The threat from Near Earth Objects raises major issues, among them the inadequacy of current knowledge, confirmation of hazard after initial observation, disaster management (if the worst came to the worst), methods of mitigation including deflection, and reliable communication with the public. The Task Force believes that steps should be taken at government level to set in place appropriate bodies – international, European including national – where these issues can be discussed and decisions taken.The United Kingdom is well placed to make a significant contribution to what should be a global effort.

The recommendations of the Task Force are given with supporting arguments in Chapter 9.

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