Hawking: Manned Mars Probe by 2025

"What is the justification for spending all that effort and money on getting a few lumps of moon rock?"

Astrophysicist Stephen Hawking asked this question at a lecture celebrating NASA's 50th anniversary at George Washington University on Monday.

Known for his pioneering work on black holes, the University of Cambridge professor certainly believes humans should go into space. Hawking suggested the moon and Mars as the first places for human colonies.

"If the human race is to continue for another million years, we will probably have to go where nobody has gone before," said Hawking.

Hawking floated weightless on a zero-gravity jet last year, even though he has the paralyzing disease, ALS, also known as Lou Gehrig's disease. He can only make small facial expressions that control a computer attached to his wheelchair. Hawking speaks through a synthesized voice by picking his words from a computer screen.

But his physical limitations have not stopped Hawking from talking about space. During the lecture, he compared space travel to Christopher Columbus' exploration and discovery of the New World.

"Spreading out into space will have an even greater effect," said Hawking. "It will completely change the future of the human race and maybe determine whether we have any future at all."

He proposed the world adopt a long-term plan to get humans into space, even if it takes hundreds or even thousands of years. He suggested goals that include a base on the moon by 2020 and a man landing on Mars by 2025.

"There will be those who will argue that it would be better to spend our money solving the problems of this planet, like climate change and pollution, rather than possibly wasting it on a fruitless search for a new planet," said Hawking. "But we can do that and still spare a quarter of a percent of world GDP for space. Isn't our future worth a quarter of a percent?"

Hawking said public interest in space declined after the last moon landing in 1972.

"We live in a society that is increasingly governed by science and technology, yet, fewer young people want to go into science," said Hawking.

A father and daughter duo, Hawking and Lucy Hawking wrote a children's book, "George's Secret Key to the Universe," an adventure based on science, to get kids interested in science.

"Some research shows that a significant percentage of students studying sciences report that their interest in science was sparked by [space]," said Lucy Hawking. "They went on to become scientists because of an early interest in astronomy and the exotic phenomena of theoretical physics. Space has the power to capture children's imagination and engage their curiosity."

And as for the question of life beyond Earth, Stephen Hawking said it's an infinite possibility, like the infinite Universe, unlikely ... but then, again, there is life on Earth.