Renowned physicist Stephen Hawking died this morning at the age of 76. In the last few years, he repeatedly warned about the threat of climate change, artificial intelligence and hostile aliens.
Here are five of his biggest warnings threatening humanity.
1. Earth could turn into Venus
The British physicist warned Earth could turn into Venus if action to halt climate change was not taken immediately. He said Venus once had conditions similar to Earth with surface water, mild temperatures and an appropriate atmosphere. The greenhouse effect burned the planet’s oceans and lands, and he believed something similar could happen to Earth if climate change continued unabated.
"Next time you meet a climate-change denier, tell them to take a trip to Venus; I will pay the fare," the physicist said.
2. Human race would have to colonize outer space in the next 200-500 years
The physicist repeatedly called for a new era of space exploration, in which nations unite towards a common goal. "It is clear we are entering a new space age. We are standing at the threshold of a new era. Human colonisation and other planets is no longer science fiction, it can be science fact," he said.
3. Warns about prospect of hostile aliens
Hawking warned against announcing our presence to any alien civilizations, especially to those more technologically advanced than humans.
“Our first contact from an advanced civilization could be equivalent to when Native Americans first encountered Christopher Columbus and things "didn't turn out so well", Hawking said in a film. "They will be vastly more powerful and may not see us as any more valuable than we see bacteria," Hawking warned.
4. Warns Artificial Intelligence may replace humans
Hawking warned that artificial intelligence will reach a level where it can replicate itself and become a new form of life that will outperform humans. At the same time, Hawking also talked up the potential of AI to help undo damage done to the natural world, or eradicate poverty and disease.
5. Humans need to leave the Earth to survive another million years
The physicist urged countries to send more astronauts to the Moon by 2020 and Mars by 2025 to 'elevate humanity', also suggesting that space agencies should aim to set up a lunar base within the next 30 years.
He believed there was no long-term future for our species staying on Earth. It would either be hit by an asteroid again or eventually engulfed by our own Sun. Travelling to distant worlds would "elevate humanity", he added.
He said human space travel was essential for the future of humanity because the Earth was under threat from climate change as well as diminishing natural resources. "I am convinced that humans need to leave Earth," said Hawking, adding that it was time to explore other solar systems as humanity is running out of space and the only places to go to are other worlds.
