Hawking says he is an optimist, but his outlook for the future of man's existence is fairly bleak. In the recent past, humankind's survival has been nothing short of "a question of touch and go" he says, citing the Cuban Missile Crisis in 1963 as just one example of how man has narrowly escaped extinction. According to the Federation of American Scientiststhere are still about 22,600 stockpiled nuclear weapons scattered around the planet, 7,770 of which are still operational. In light of the inability of nuclear states to commit to a global nuclear non-proliferation treaty, the threat of a nuclear holocaust has not subsided.
In fact, "the frequency of such occasions is likely to increase in the future," says Hawking, "We shall need great care and judgment to negotiate them all successfully."
Even if humans manage to avoid a nuclear stand-off over the next thousand years, our fate on this planet is still pretty much certain.
"Life on Earth will have disappeared long before 7.6 billion years," says Smith, "Scientists have shown that the Sun's slow expansion will cause the temperature at the surface of the Earth to rise. Oceans will evaporate, and the atmosphere will become laden with water vapor, which (like carbon dioxide) is a very effective greenhouse gas. Eventually, the oceans will boil dry and the water vapor will escape into space. In a billion years from now the Earth will be a very hot, dry and uninhabitable ball."
Finally, between the next thousand years or so that Hawking says it will take man to make the planet uninhabitable and the billion years it will take for the sun to turn our planet into an arid wasteland, there is always the chance that a nearby supernova, an asteroid, or aquick and painless black hole could do us in.
One way or another, the life on Earth will likely become uninhabitable for mankind in the future. We need to start seriously thinking about how we will free ourselves from the constraints of this dying planet.
Why We Should Reject This Idea
"The nearest star [to Earth] is Proxima Centauri which is 4.2 light years away," saysUniversity of Michigan astrophysicist Katherine Freese, "That means that, if you were traveling at the speed of light the whole time, it would take 4.2 years to get there."
Unfortunately, at the moment we can only travel at about ten thousandth of light speed, which means if man were to use chemical fuel rockets similar to the those used during the Apollo mission to the moon, the journey would take about 50,000 years. Without the use of a science-fiction-like warp drive or cryogenic freezing technology, no human would live long enough to survive the journey. In addition, "the radiation you would encounter alone would kill you, even if you could get a rocket to go anywhere near that fast," says Freese.
On the upside, if man ever develops the technology to travel at the speed of light while remaining shielded from cosmic radiation, he could effectively travel into the future. "A five year trip at light speed could push an astronaut forward by 1000 earth years," says Freese, "If he wanted to see if any humans were still around by then."