This may be of general interst.
Get Ready: Mars Reverses Its Course In the Sky Saturdayhttp://www.msn.com/en-us/weather/topstories/get-ready-mars-reverses-its-course-in-the-sky-saturday/ar-BBrO8dD?li=BBnb7Kz
See, that’s why Mars no longer has an atmosphere. Every time Mars reverses course it loses a bit of atmosphere, until over the years it has almost none left. Silly NASA scientists think they can send people to live on Mars. They haven’t thought this through. Every time Mars reverses course the people and their supplies will go flying off into the solar system.
Is it possible, or could it eventually be possible, to alter the atmosphere on a planet to suit us?
I may have heard a SETI person (possibly Seth Shostak) state that if we find a planet that is nearly ideal for us to live on we may eventually have the technology to alter its atmosphere.
Is it possible, or could it eventually be possible, to alter the atmosphere on a planet to suit us?Of course it is possible. We're altering Earth's atmosphere. The problem is the amount of time it takes unless the planet already has an atmosphere closely similar to ours. As for Mars, it ain't gonna happen. Mars does not have a magnetic field to deflect solar winds and radiation, so no matter what we try in its very thin atmosphere will get stripped away quickly.
I may have heard a SETI person (possibly Seth Shostak) state that if we find a planet that is nearly ideal for us to live on we may eventually have the technology to alter its atmosphere.As much as I appreciate what Seth is doing with SETI, he's a dreamer when it comes to humans inhabiting other planets. Identifying a suitable planet may be within our technological ability in the future, but getting there is another matter. Lawrence Krauss addressed this in one of his books about the physics in science fiction. Accelerating a school bus size craft to 0.25C would take more energy than exists in our solar system, at the very least. Even traveling at 0.25C it will take decades to get to any other star system, and we'll have to send robotic probes ahead to make sure we find a suitable planet. Then we have to alter the atmosphere for our biology. By the time that is done we'll either be extinct or not need to travel to another solar system because of technological advances or societal collapse.
The way I understood the presentationis was that Mars does not really reverse its course, but only seems to do this relative to Earth… It moves slower than earth, so when their orbits have a certain mathematical shape, if Mars is ahead of us in its orbit, Earth (in its orbit) catches up and leaves Mars behind, giving the relative appearance of a reversal by Mars.
It's easy to understand why Mars will chart this odd path in the sky if you remember that the Earth is nearer to the sun than Mars is, and is therefore circling around it toward the east faster than the Red Planet. At the end of May, Earth will overtake Mars, passing between it and the sun, and will move on ahead, leaving Mars behind. While we're in the midst of passing it, the planet will seem to move backward toward the west, just as a slower car seems to drop behind when it is viewed from a faster one on a highway. With the right perspective, it's simple to understand, yet the apparently backward paths of the planets confused the wisest men for centuries until Copernicus provided the correct explanation. [The Greatest Astronomers of All Time]
The way I understood the presentationis was that Mars does not really reverse its course, but only seems to do this relative to Earth.. It moves slower than earth, so when their orbits have a certain mathematical shape, if Mars is ahead of us in its orbit, Earth (in its orbit) catches up and leaves Mars behind, giving the relative appearance of a reversal by Mars.So you're saying our astronauts won't go flying when Mars reverses course?It's easy to understand why Mars will chart this odd path in the sky if you remember that the Earth is nearer to the sun than Mars is, and is therefore circling around it toward the east faster than the Red Planet. At the end of May, Earth will overtake Mars, passing between it and the sun, and will move on ahead, leaving Mars behind. While we're in the midst of passing it, the planet will seem to move backward toward the west, just as a slower car seems to drop behind when it is viewed from a faster one on a highway. With the right perspective, it's simple to understand, yet the apparently backward paths of the planets confused the wisest men for centuries until Copernicus provided the correct explanation. [The Greatest Astronomers of All Time]
no, no, no, its the greatest opportunity to fly straight to Mars when it stands still before reversing its course. Easy plotting!
Or we can just launch and have the rocket park in Mars’ orbit waiting for it to catch up to the rocket!! Even easier.
Of course with all that traffic nowadays, Mars may be late arriving and our astronauts will run out of potato chips.
I hadn’t thought of that. Just think of all the fuel they can save. Green pioneering! They may need extra reading material as well as snacks.