Scientists have concluded that liquid water once existed on the surface of Mars. This was suspected ever since probes orbiting Mars took high resolution images of what appeared to be dried up river tributaries. The most compelling evidence comes from the rovers (Opportunity, Spirit, and Curiosity) rovers which were able to perform several experiments on surface rocks there. Your mission is to research the data and report the findings. In the process, you will learn a bit of geology that is occurring on the Earth as well. Please do not simply cut/paste web material but use your own words.
Part 1: Please find four different clues that water once flowed on Mars (in the distant past). 2 points each
There are several clues that have convinced planetary geologists that Mars once had an abundant supply of water. I would expect you to report on 4 of the following discoveries.
The Phoenix lander discovered
water ice just below the surface (away from the polar caps).
Opportunity discovered the mineral
hematite (basically rust) in sedimentary layers. This mineral forms in
the presence of water on earth.
Another mineral, jarosite, was also
found which forms in the presence of acidic water on earth.
Deposits of several minerals (including
gypsum and sulfur) have been found which (on earth) form when water
evaporates ... leaving behind these insoluble mineral deposits.
Close-up
images from Opportunity reveal crossbedding patterns in sedimentary layers
... suggesting they were formed by gently flowing salt water.
Strong evidence of groundwater came from
the discovery of
Vugs ... small cavities in rock which form when percolating ground water
dissolves minerals.
The Mars Reconnaissance Orbiter has taken
images which suggest that salty water may actually be flowing on Mars during
summer.
The Curiosity rover has actually found
that the soil contains
2% water (by weight). The soil releases the water when heated.
However, the image above of Martian "blueberries" may NOT be evidence of water on Mars. They were originally used as strong evidence of water on Mars but now may be remnants of meteorites.
Part 2: Is there any evidence that water is currently flowing on the Martian surface now? If so, where is it and how is that possible since the class material clearly states that liquid water can not currently exist on the Maritan surface? 10 points
In September 2015, NASA announced that images from the Mars Reconnaissance Orbiter detected water flowing down steep slopes in the form of (warm) seasonal "dark streaks". The water then quickly evaporates. It is unclear what the source of the water is. My guess is it percolates up from a deep aquifer .. much like you find in an artesian well. This liquid water is salty (mixed with hydrated minerals known as perchlorates) which act like antifreeze ... allowing the water to remain in the liquid state for a short time. This raises the hope that microbial life may exist on Mars (although some argue this water is too briny to support life). Learn more here.
Part 3: Why is it unlikely we will send our current rovers to any potential sites of liquid water? 2 points
Microbial contamination! The search for life starts with a search for water. If liquid water is discovered, the last thing we want to do is go there and introduce Earth microbes. This could destroy any native life forms. With current technology and costs, rovers are not 100% sterile (even though great efforts are taken to decontaminate all spacecrafts). So odd as it sounds, the search for life could destroy it.