1) Why is Mars’ atmosphere so thin?
All terrestrial planets were born with a certain complement of gases in
the rocks. The volcanic overturning of their mantles allowed much of
these gases to escape, forming their atmospheres. But for Mars, the
planet is too small for it to have fully overturned the mantle (it
cooled too quickly, and hence the mantle is now too frozen to overturn
as easily). So Mars didn’t get a chance to outgas all of the
volatiles in its mantle. Hence it has a smaller atmosphere.
2) Does the channel connected to Gusev Crater lead to the crater or
away from it?
The channel, called Ma’adim Valles, leads into Gusev Crater. This
is why the Athena science team suggested that there could have been a
lake in the past in Gusev. In very early times, when Ma’adim was
very active, it not only entered Gusev from the south but actually
continued through the crater and eroded the northern rim. We have traces
of an overspill to the north. As soon as the discharge lowered, water
was trapped in Gusev Crater.
3) I know that the rovers can grind rocks, but can they drill into
the soil?
By commanding the rovers to stop five wheels while moving the sixth
wheel slowly, we can dig a trench in the soil on Mars. Then we can
analyze the differences in the soil from the surface to the bottom of
the trench to understand how the soil was formed.
4) Do you think that the scientists at JPL and NASA will ever send
robots to Mars to assemble a bigger vehicle to survey the land?
Engineers are thinking about the possibility of sending a heavier
payload to Mars in pieces and assembling these pieces together into
larger equipment. This may be an interesting alternative method to
solving hardware problems. I can imagine a large rover driving on Mars
followed by small, assistant robots or having something like a
helicopter recognizing the far terrain for a future rover visit. There
is no limit to the possibilities. I am sure
engineers
at JPL and NASA will be able to construct our dreams.
5) Is there enough light on Mars to grow plants?
Yes, in particular around the equator. We may be able to have algae,
plankton, grass and other small vegetation growing with less sunlight.
Larger plants like corn, rice and potatoes will require more than just
light. Of course, liquid water, nutrients and heat are also required for
plants. I am sure we will have our “green martians” should
these conditions be found or created on Mars.
6) Why are all the rocks we see on Mars so small?
The rocks we saw in the Viking Landers and Pathfinder pictures are
larger than the ones we are seeing from Spirit and Opportunity. The
places we carefully chose to land the Mars Exploration Rovers have
smaller rocks because these locations are safer for landing and roving.
Large rocks would damage the airbags or the rover itself during the
landing operations. Larger rocks are there. On the other hand, for
example, erosion processes are common on our Planet. These processes
remove soil layers from the higher lands exposing the rocks we see
today. Rain is an important player in this process. Since we have much
rain on Earth than on Mars, we should expect to see smaller rocks on
Mars. Therefore, the big rocks might be there waiting to be revealed.
7) What have you discovered about Mars that you didn’t know
before?
We have discovered many things on Mars. We were expecting a
concentration of iron in a high
oxidation state. The rocks
and soil, especially in Gusev Crater, have approximately 60–70% of
their iron atoms as Fe2+. This means the chemical weathering (e.g., by
water) was not very intense at Gusev Crater. The soil looks like a
just-cut apple. If you leave it for some hours in the open air it will
be oxidized. The well known hematite is made exclusively of Fe3+. Red
soils on Earth are like this because of this hematite (from Greek:
hema=red). On the other hand, hematite is a strong pigment. This means
that a small amount will make it red. We have discovered that Meridiani
Planum is a place where liquid
water was abundant. Crystalline hematite and jarosite are formed
where water is present. Hematite concretions, like those nice
blueberries, are also a nice discovery. Mars was once warmer and wet.
Possibly a suitable place for life. Today it is dry and cold. I am
afraid Earth is going in the same direction. Looking to Mars I realize
how wonderful Earth is, and how important it is to take care of our home
planet.
8) What is the difference between cross-bedding and layering?
By definition, cross-bedding is a bedding that was inclined when
deposited. It is formed by wave actions, wind (e.g., sand dunes). Their
slopes are downwards in the direction the wind blows or the water moves.
Bedding is a division of sediment or sedimentary rock into parallel
layers (beds) that can be distinguished from each other by such features
as color, chemical composition or grain size. Bedding planes are assumed
to be originally (nearly) horizontal for water-laid sediments. Layering
is a bed or stratum of rock. We can also refer to layering as a bed of
sediments that form when settled out of water.
9) Why does the panoramic camera have such a wide mast? What’s
inside it?
First, the camera bar atop the mast is as wide as it could be made while
still being able to fit while stowed on the rover deck. The wider the
separation of the cameras, the better stereo ranging information can be
obtained. Second, the "pipe" part of the mast is wider than it might
intuitively appear to need to be because it is also acting as a
periscope for Mini-TES, inside the rover body. The mast is just
slightly wider than the light beam that enters Mini-TES.
