Toronto, May 3 (IANS) Accusing world famous astrophysicist Stephen Hawking of spreading misinformation about threats from aliens, former Canadian defence minister Paul Hellyer claimed Sunday that extraterrestrials have actually been visiting earth for decades.

Rather than harm mankind, he said, their (aliens') spaceships have provided us information for triggering today's microchip and IT revolution on our planet.

Hawking has recently warned humanity against contacting aliens. 'If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans,'' the British astrophysicist has said.

According to Hawking, if human beings tried to contact aliens, they could invade us and take away our most important resources. 'If they (aliens) wanted to use our solar system, for some super project, our complaints would be like an ant colony protesting the laying of a parking lot,'' Hawking has said in a new documentary.

Hawking has also said that though most extraterrestrial life could be only in the form of small animals, but there could also be 'nomads, looking to conquer and colonize'' other planets. Taking issue with Hawking Sunday, the former Canadian defence minister, who himself is an expert on the subject and has has been speaking about aliens for years, said aliens have already visited earth and contributed to our technological advancement.

Hellyer told the Canadian Press that 'the reality is that they (aliens) have been visiting earth for decades and probably millennia and have contributed considerably to our knowledge.'' He said our computer screens have their origins in alien spaceships. 'Microchips, for example, fiber-optics, they are just two of the many things that allegedly - and probably for real - came from crashed vehicles,'' the Canadian said.

Blaming Hawking for scaring mankind about aliens, he said, 'He (Hawking) is indulging in some pretty scary talk there that I would have hoped would not come from someone with such an established stature. 'I think it is really sad that a scientist of his repute would contribute to what I would consider more misinformation about a vast and very important subject.''