James Van Allen's Last Science Paper

Author: * Sokni Hvitaskald - 10 Posts on this thread out of 1,073 Posts sitewide.
Date: Aug 29, 2006 - 20:21

By Abigail W. Leonard
Special to SPACE.com
posted: 29 August 2006
06:14 am ET

Until his death this month at the age of 91, James Van Allen continued to do work that had fascinated him since childhood and made him a leading figure of America's Space Age.

Van Allen spent a lifetime exploring the universe, and is most famous for discovering the radiation belts circling Earth which now bear his name.

In what would be his last paper, he explored a subject that hits somewhat closer to home: The likelihood of an asteroid colliding with Earth.

Asteroid watch

The research, published in this month’s American Journal of Physics, details how the likelihood of such an event is enhanced by the gravitational pull between the two bodies.

The research shouldn't raise concern about possible collisions though, said Dave Tholen, an astronomer at the University of Hawaii. "It can happen, but I wouldn't worry about it. We are actively discovering near-Earth asteroids and computing their orbits to monitor the situation.”

Tholen said astronomers are intensely focused these days on an asteroid called Apophis, which is set to pass less than 24,000 miles from Earth on April 13, 2029. Van Allen’s paper, which details how scientists estimating the probability of a collision should take Earth’s gravitational pull into account, could help researchers calculate whether the asteroid will become a threat.

Beyond imagination

Colleagues say this and other examples of Van Allen's work are remarkable not only for what he found, but also because of the simple experimental designs he employed.

Read the rest at:
http://www.space.com/scienceastronomy/060829_science_tuesday.html