A few months ago, famed British cosmologist Stephen Hawking presented a lecture on the survival of the human race. According to him there is only one way for humanity to survive the next thousand years. We must get off the planet and colonize space.

Earth is fragile. Our environment is delicately balanced. Small changes in temperature, chemical makeup of the atmosphere and variations in the geomagnetic field could change life as we know it.

The continuous threat of a catastrophic near-earth object (NEO) event that could end all life on the planet, worldwide nuclear war, the natural aging of our sun, a viral pandemic or a series of large volcanic eruptions could end humanity on Earth. Unfortunately, it is inevitable that at least one of these events will occur sometime in the next decade, century, millennium ... no one knows when, but it will happen.

World leaders are concerned with the survival issue and a great deal of energy and focus have been expended on the so-called "climate change" threat to the world's population. Even though convincing evidence regarding man's impact on the climate remains elusive, this topic has become politically charged.

Common sense and scientific facts appear to have been largely left behind. World economies are being saddled with new energy policies that restrict progress. The followers of the "Church of Renewable Energy" have taken on the aura of a religious cult. In fact, there are many other threats to life that are much more likely to happen.

Hawking believes a NEO event may be the most probable threat to humanity. He notes, for example, that one of the major factors behind the scarcity of intelligent life in our galaxy may be the result of asteroid or comet collisions with planets.

In his Life in the Universe, Hawking points out the collision of the Schumacher-Levi comet with Jupiter in 1994 produced a series of enormous fireballs with plumes many thousands of kilometers high that left large dark "scars" on the atmosphere.

These hot "bubbles" of gas lasted for several weeks. Furthermore, scientists believe the collision of a smaller NEO with the Earth, about 70 million years ago, was responsible for the extinction of dinosaurs. All life was not lost at that time, but anything as large as a human would have almost certainly been wiped out.

Based on Earth's history, we know that such collisions occur about once every million years. If this estimate is correct, intelligent life on Earth has developed only because of the lucky chance that there have been no major NEO events in the last 70 million years. According to Hawking, other planets in our galaxy upon which intelligent life would have developed may not have had a long enough period to evolve.

While it is true that the threat of a NEO event is being taken more seriously in scientific and political circles, little progress is being made toward alternative solutions. Diverting an approaching NEO continues to be studied, but proposals lack economic and technical realism.

Space colonization is extremely complex, but it offers an alternative to being stuck on a planet without an escape plan if and when one is needed. Yes, we should continue to take good care of Earth, but there is only so much that can be done. Ultimately, the planet will die.