| MadSci Network: Astronomy |
If you want to make a voyage to Mars, you will be in outer space for at least two years. Mars is further away from the sun, so its revolution takes much longer than the revolution of planet Earth:
a year on... Earth = 365 days 5 hours 48 minutes 11 seconds
a year on... Mars = 687 days
Therefore, when you take off, make the trip to Mars (that takes several months), and want to come back after e.g. three weeks, this is impossible: planet Earth is too far away, because it orbits the sun much quicker. So you will have to wait until planet Earth has made one orbit. This takes another nine months, which you will have to spend on Mars. And when you finally take off for Earth and come back, it has been nearly two years since you left Earth.
So, you have spent two years without gravity (which hardly exists on Mars, it is about 1/3 of that of the Earth). There have been astronauts in the Russian space-station "Mir" for one year and eighteen hours, and when they came back, they had to get used to the force of gravity on Earth first. So staying in outer space for two years is not a very good idea. But many astronauts now take a home-trainer with them, to stay fit. So that problem can be overcome.
But think of all the oxygen you would have to take with you on a trip to Mars: there is no oxygen on Mars (well, a little bit, but not enough by far) or in space, so all the oxygen you will use in two years will have to come with you in the spaceship. I wonder if that fits...
Some scientists have other ideas: some say that we have to transport plants to Mars. The air on Mars consists almost completely of carbon-dioxide. Trees breath in carbon-dioxide and breath out oxygen (with humans it is exactly the other way around). So if we wait for many years, the air on Mars will be breathable for us humans. But most people don't want to wait so long.
Unfortunatly before we can go to Mars we will first have to solve these problems. And then, the first men on Mars can go make a "giant leap for mankind".
Try the links in the MadSci Library for more information on Astronomy.