Astronomy

# How far away is Mars

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In 2004, George W. Bush announced that humanity was going to Mars. NASA has stated that the goal is to put a man on Mars by 2037, after first completing some Moon missions by 2020. There are many hurdles to overcome if we are to reach our goal, none greater than the sheer distance between our planet and Mars. While the biggest obstacle may be the ever changing distance between the planets, Mars is farther away from the Sun as well.

So how far away from the Earth is Mars? Well, when determining the distance from Earth to Mars, the distances can vary greatly. When Mars is at opposition, it can be as close as 35 million miles from the Earth. When Mars is at its farthest point from Earth, it can be as far as 250 million miles away from Earth. This happens because Mars has an eccentric orbit, or it has an orbit that is slightly more elliptical than circular.

In fact, the only planet that has a more eccentric orbit than Mars is Mercury. The orbital eccentricity of Mars is 0.09, while the orbital eccentricity of Mercury is roughly .20. To put this in simpler terms, the orbital eccentricity for a perfect circle is exactly zero, while the orbital eccentricity of an ellipse is one. This orbital eccentricity is caused by the gravitational tugs of the other planets.

How closes can Mars come to Earth? At just before six in the morning on August. 27, 2003, Mars came within 34,646,418 miles of Earth. This was the closest that Mars had come to the Earth in almost 60,000 years, or during the time of the Neanderthals.

This close alignment came about because Mars was at a perihelic opposition. This means that while Mars was at its closest point to the Sun, it was also at its closest point to the Earth. That is pretty amazing stuff, and the two planets will not be this close again until the year 2287.

How far away is Mars from the Sun? At perihelion, or the closest it will be to the Sun, Mars is roughly 128 million miles away from the Sun. At aphelion, or the farthest point in the orbit, Mars will be about 158 million miles away from the Sun. This difference in distance is again caused by the elliptic orbit of Mars.

Earth is about 93 million miles away from the Sun, so this means that Mars is about 35-65 million miles farther away from the Sun at any given time than the Earth is. As an interesting side note, Mars can be as cold as -199 degrees Fahrenheit during a polar night, and as warm as 80 degrees Fahrenheit at the equator.

The weird orbit of Mars means that it will never be the same distance away at any given time. This will be of utmost importance to mission planners, astronauts, and government officials who will be of critical importance to making sure that the goal is seen all the way through. Can we get to Mars? It is possible, and now we know how far we need to go to get there.

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