Stephen Hawking, one of the world's most important scientists, believes that to survive, humans must move into space: "Once we spread out into space and establish independent colonies our future should be safe," he says.
Today, the United States, India, China, and Japan are all planning to send astronauts back to Earth's closest neighbor: the moon. Each country wants to create space stations there between 2020 and 2030. These stations will prepare humans to visit and later live on Mars or other Earth-like planets.
Robert Zubrin, a rocket scientist, thinks humans should colonize space. He wants to start with Mars. Why? There are several advantages: for one, sending people to the moon and Mars will allow us to learn a lot -- for example, whether living on other planets is possible. Then, we can eventually create new human societies on other planets. In addition, the advances we make for space travel in the fields of science, technology, medicine, and health can also benefit us here on Earth.
But not everyone thinks sending humans into space is a smart idea. Many say it's too expensive to send people, even on a short journey. And most space trips are not short. A one-way trip to Mars, for example, would take about six months. People traveling this kind of distance face a number of health problems. Also, for many early space settlers, life would be extremely difficult. On the moon's surface, for example, the air and the sun's rays are very dangerous. People would have to stay indoors most of the time.
Despite these concerns, sending people into space seems certain. In the future, we might see lunar cities and maybe even new human cultures on other planets. First stop: the moon.
