Re: HOW FAR IS MARS FROM THE EARTH?

Mars is a good choice for a travel destination. When it is at its closest to the Earth, called favorable opposition by astronomers, it is only about 35 million miles away. At its greatest distance from the Earth the trip would be about 250 million miles, so travel dates should be considered carefully.

People have always been interested in Mars, but serious consideration about the nature of the planet began in 1659 when Christian Huyguens, using a refracting telescope, first observed a large dark feature on the surface of Mars. By watching this feature he determined Mars has a day length about the same as the Earth. A few years later Giovanni Domenico Cassini observed the polar caps of Mars and then a century later William Herschel determined that Mars axis is tilted. This made it possable to predict that Mars would undergo seasons as does the Earth. In 1877 Giovanni Virginio Schiaparelli noticed what appeared to be canals crossing the surface, leading to speculation that Mars was or had been inhabited.

In 1976 the first explorer from the Earth landed on Mars. This explorer was actually a remotely controled machine called the Viking lander. The data returned from Viking and later missions has provided quite a good description of Mars. It is a desert planet with a thin atmosphere made mostly of carbon-dioxide. While the high concentration of carbon-dioxide might lead you to expect a green house effect on Mars, the atmosphere is much too thin (about 1% of Earth's) to keep heat from the planet from escaping out into space. Because of this the atmospheric temperature can vary from -220 deg F at night to a high of 70 deg F during the daytime. With such a broad temperature range vegetation on the surface is non-existent.

People would like to travel to Mars someday mainly in the spirit of scientific observation. To stay on the planet for any length of time, they would need to bring almost everything they would need for survival. Scientists expect to find water either underground or locked into the polar ice caps, so water and oxygen produced by breaking the water down could help sustain explorers, but first they would have to find it. How long they could stay would depend on how big an expedition could be mounted and how much provisions they could bring along. One project, which I believe is now on hold for bugetary reasons would put four explorers on Mars for about two years.