Detecting life on another planet would be the discovery of the century, and Mars rovers are hot on the trail to make history. Lending them a helping hand is a 21-year-old at Washington State University, Kellie Wall.
The geology major recently discovered a new way to detect evidence of past water on Mars. Since water is considered a crucial ingredient in the complex cocktail that makes life possible on Earth, its existence on Mars would further studies in this field.
“This could be the foundation of finding environments which could have sustained life [on Mars],” Wall said in a WSU video interview.
The key is locked inside volcanic rocks both on Earth and Mars.
Wall identified the chemical composition of volcanic, igneous rocks on Earth using a device called an x-ray diffraction machine, the same type of machine that NASA included on their Curiosity Mars rover that’s been exploring the Martian surface since August 2012.
What Wall found when she did this was a straightforward way to look back in time and see if water was around when the magma cooled.
Her method hinges on the rocks’ crystal structure: the pattern that the atoms and molecules form inside rocks and determine the rocks’ stability. Geologists differentiate rocks based on four categories of crystal structure: Rocks that are completely crystalline are the most stable, and rocks with little or no uniform crystal structure, like a type of volcanic glass called obsidian, break easily.
The different types of igneous rock that Wall observed from past volcanic eruptions in the Northwest US, New Zealand, and Italy were somewhere in between the two extremes, containing both crystalline and non-crystalline material.
This is because when liquid molten rock contacts water, it flash-freezes, cooling far more quickly than without water. The flash freezing produces glass, a non-crystalline material. Wall discovered an upper limit on the number of crystals a rock can contain that is associated with flash freezing.
Beyond her upper limit, rocks likely do not form in the presence of water. Using the x-ray diffractor machine below, she could see inside the rock and count the crystals, which led to her results.
When Wall applied her measurement scale to rock samples analysed by Curiosity’s x-ray diffractor, she discovered no evidence of past water. This is not surprising, however, since Curiosity is exploring a region on Mars called Gale crater, which has limited evidence of nearby volcanic activity. The result, however, has not discouraged Wall.
“…being able to determine the environment through the texture of a volcanic rock is something pretty cool and different,” she said in a press release that WSU issued on Oct. 3. “I think it’s an interesting avenue for future research.”
Moreover, Mars is home to the largest volcano in our solar system, Olympus Mons. It dwarfs Mt. Everest, standing three times higher than Earth’s tallest mountain. Mars also has a number of other volcanoes on its surface, so there is plenty of spots for Wall to investigate in future missions.
Wall is the lead author of a paper detailing the work, which was recently published in Nature Communications. Watch Wall explain the process in the video below.
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