Space Probes Feel Cosmic Tug of Bizarre Forces

[Tombstone]

By Robin McKie

Science Editor

The Observer - UK

Something strange is tugging at America's oldest spacecraft. As the Pioneer 10 and 11 probes head towards distant stars, scientists have discovered that the craft - launched more than 30 years ago - appear to be in the grip of a mysterious force that is holding them back as they sweep out of the solar system.



Some researchers say unseen 'dark matter' may permeate the universe and that this is affecting the Pioneers' passage. Others say flaws in our understanding of the laws of gravity best explain the crafts' wayward behaviour.



As a result, scientists are to press a European Space Agency (Esa) meeting, called Cosmic Visions, in Paris this week for backing for a mission that would follow the Pioneers and pinpoint the cause of their erratic movements.



The strange behaviour of the Pioneers - which swept by Jupiter and Saturn in the Eighties - was discovered by John Anderson and Slava Turyshev of the Jet Propulsion Laboratory in Pasadena and Michael Martin Neito of the Los Alamos National Laboratory.



Check out the whole story:

http://www.guardian.co.uk/space/article ... 21,00.html