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Making Tracks on Mars
An anonymous reader writes "In a remarkable series of orbital pictures, the Mars Global Surveyor's cameras have imaged the tracks of the Spirit rover on the surface. Individual debris pieces including the backshell and lander are visible with remarkable clarity using an innovative roll of the satellite."
It is a line camera, X resolution is set by number of pixels, Y resolution by mars rotation speed and number of scans per second. If the satelite rolls opposite to mars rotation, it is as if mars rotates more slowly, therefore higher Y resolution. Price to pay is you end up rotating out of view, so smaller pictures, but more detailed ones.
10 ?"Hello World" life was simple then
I don't think it would be more massive than the one left on Earth by the Genesis probe...
Keep imagining...state of the art spy sattelites can supposedly read license plates and even the rank insignia's on a soldier's uniform.
Hubble has already imaged Mars. The resolution is nowhere close to these new images from MGS. They are images of the entire planet. Check them out here: http://hubblesite.org/newscenter/newsdesk/archive/ releases/1999/27/
If you think the images from Mars Global Surveyor look awesome, the images from the upcoming Mars Reconnaissance Orbiter should be nothing short of AWESOME.
Given that MRO will likely use a modified version of the same camera system used on the Ikonos imaging satellite (Ikonos can resolve down to 100 cm resolution from a 300 km orbit through Earth's thick atmosphere), the combination of the lower orbit and the very thin atmosphere on Mars means there are estimates that the MRO cameras could resolve objects as small as 150 millimeters across in the visual light spectrum! At that resolution, MRO could finally put to bed the controversy about the anomalous features on the Cydonia plain of Mars that some people claim are not natural features of that plain.
The problem with breathing is something called "partial pressure". Partial pressure is the pressure exerted by an individual gas in the atmosphere. You have to have a bare minimum oxygen partial pressure of around 2.4in Hg in order to push enough oxygen through the lining of your lungs and into the bloodstream. That's the pressure at about 2 miles up. 6" Hg is about normal partial pressure at sea level.
r es/Gases06.htm
Here's the first hit off of Google for partial pressure:
http://wine1.sb.fsu.edu/chm1045/notes/Gases/Mixtu
You also have to have enough air pressure to keep water from boiling at room or body temperature, whichever is higher. Say, about 3" Hg, which is about 10% of normal. That's not much margin of error. Plus, an extremely dry atmosphere will suck the water right out of you.
You also need a small amount of CO2 to help regulate breathing. Too little and you tend to hyperventilate.
Nitrogen for plants. Actually, most plants don't use free nitrogen in the atmosphere, but fixed nitrogen (nitrates) in soil. The plants that fix the nitrogen do need the gas.
And then you have to have some protection from solar radiation.
I did this seat-of-the-pants, probably got some of it wrong, but the numbers should be somewhere in the ballpark. Anyway, the simple answer is that it's not that simple.
Why should we? What possible reason is there to keep every damn thing in the universe in pristine, untouched condition? Besides, it's not like we're going to Mars and throwing a McDonald's bag out the window, scattering burger wrappers and half-eaten McNuggets all over the Martian surface. These are spacecraft components that, first chance we get, will probably be brought back to Earth and examined.
If a job's not worth doing, it's not worth doing right.
Without a stable magnetic field to deflect the solar wind, any attempt to increase the atmospheric density on Mars is never going to work. It would be like trying to inflate a balloon with a hole in it. Deatils here.
Bush Lies On the Record.
I would be interested to see if the Viking landers are still visible
i ng_040107.html
http://www.space.com/scienceastronomy/mgs_mpf_vik
Table-ized A.I.
Unfortunately for this hypothesis, Venus has no magnetosphere, experiences much stronger solar wind than Mars, and has no shortage of atmosphere.
So Mars' lack of atmosphere is likely due to a combination of factors, with the lack of magentosphere being perhaps necessary but hardly sufficient. The question for terraformers is whether or not it is possible to create and sustain an environment like the one we have on Earth via biological means.
It is worth noting that in the absence of life, Earth would be a lot less habitable than it is. That is, life on Earth has created conditions that are suitable for life on Earth. Or more correctly, life on Earth has found relatively open evolutionary niches due to the actions of other life on Earth. The most obvious thing like this is oxygen, which would weather out of the atmosphere in a few million years were it not a waste product thrown away by plants.
--Tom
Blasphemy is a human right. Blasphemophobia kills.
Actually, with regard to point #2, the earth and moon are a double planet system, because the moon orbits the sun, not the earth, as evidenced by the fact that it always falls towards the sun. More here: http://www.copernicus.org/EGS/egsga/nice00/program me/abstracts/aac6816.pdf
Marvin knew: "Think of a number, any number..."