Mars
4th rock from the Sun, and last of the terrestrial planets-Mars.
Though Mars is half the size of Earth, its cold, barren surface is about the area of all earth's dry land-and many think its majestic canyons and giant volcanoes should be humanity's next port of call...
In the 19th century, Mars-the Red Planet-was thought to be a place of huge canals and aliens...
In the 20th century, humans explored the planet close up with spacecraft, and found it lifeless.
...And in the 21st century, you may be one of the first explorers to land on Mars.
The water may be gone from the surface but maybe it's not "gone" completely, maybe it is near the
surface and maybe there's processes that we don't quite understand that's causing a water
turnover, maybe underground in ways that we still haven't figured out.
And so the question of whether or not there's still a cycle, whether the water cycle is turning
over in a completely different manner than it does on Earth... we don't know whether that's true
or not, but it's certainly a very exciting time to be studying both Venus, Earth and Mars.
Revolution
Rotation
Radius
Distance From the Sun
686.98 Earth days
1.025957 Earth days
3,397 km
227,936,640 km
Mass
Density
Surface Temperature
Moons
0.64191 x 1027 grams
3.94 gm/cm3
27° to -133° C
two: Phobos and Deimos
Atmosphere
Craters
Volcanoes
Water
carbon dioxide, nitrogen and argon
northern hemisphere has fewer than the southern hemisphere
Olympus Mons is the largest volcano in the solar system
The recent discovery of olivine, which weathers easily by water, in abundance
on the surface may mean that earlier beliefs that water
was/is present could be incorrect.
You wake up early and you look and you see that salmon-colored sky with those clouds whisping
across the surface.
You'd see the sun rise bright and orange through that salmon-colored dust filled sky in the
morning, and you'd see it rise up. And the sky would never be blue, it would remain that sort of
pinkish-salmony color.
You look out at the pictures of this rock-strewn field, and you could imagine walking on that
surface from the rover's wheel tracks in the soil, you could imagine the footprints that you
would leave. And you could imagine going over to Yogi and Barnacle Bill, and looking at them up
close and looking around, you could kind of imagine what the surface would be like to walk on and
what you would look at as you did that.
And finally, if you could be on Mars without a spacesuit, which of course you can't, we now have
the data from the weather station to actually feel what it would be like to be on Mars. Viking
just didn't have enough sensors and they couldn't measure fast enough. But we know that if we
were standing on the surface, our feet would be comfortably warm, band our head would need
(laughs) a big hat and a scarf, it would be cold up there. 20 or so degrees of variance between
the surface and where you're standing at, and then just standing there for a moment or two, we'd
get 10-15 degree temperature swings just as we were standing there you'd be cold and hot in an
instant. And finally just sort of feel these light breezes that were blowing on the surface.
And so those really kind of make it into a place where you could actually imagine being on the
surface. And that's kind of fun... (laughs)
Take a VIRTUAL MARS tour of the Pathfinder landing site with Matt Golombek and others as your personal guides, using RealVideo clips.
Claudia Alexander
U.S. Project Scientist, Rosetta comet mission
Jet Propulsion Laboratory, NASA/Caltech
Matt Golombek
Project Scientist, Mars Pathfinder
Jet Propulsion Laboratory, NASA/Caltech
video
audio
Missions:
Mars Global Surveyor
2001 Mars Odyssey
Mars Pathfinder
Recent Articles:
NASA Outlines Mars Exploration Program For Next Two Decades
MOC Images Suggest Recent Sources of Liquid Water on Mars
Additional Links:
JPL's Solar System Exploration
The Nine Planets
Views of the Solar System
Windows to the Universe