On April 26, John Grotzinger, a Professor of Geology at the California Institute of Technology, told the Stony Brook University audience about the possibility of Mars previously having a habitable environment. While the giant planet is known for its reddish color, Grotzinger’s discovery of gray colored rock signified the possibility of life, which left scientists and Mars enthusiasts in the room in awe.

Grotzinger served as the Chief Scientist of the Mars Science Laboratory Rover, Curiosity. The Curiosity rover was announced to start its two-year mission in 2012 to discover if Mars was ever able to support microbial life and Grotzinger made headlines when rumors spread about the rover possibly finding signs of life.

His work found that while Mars is red, when drilled a couple inches into the ground, the rock is gray-colored at Gale Crater, meaning that the iron there is not fully oxidized. Grotzinger said that “these rocks are gray because they formed in a lake where the iron was produced and it’s not able to form this mineral called hematite.” Hematite would’ve given the rock a reddish-black color, but magnetite was found instead; and in magnetite, iron is not fully oxidized.

Gale Crater on Mars is the main location where geologists and planetary scientists are searching for habitable environments. Gale belongs to a family of filled craters that were eroded. Grotzinger said, “Mars once had a warmer climate that allowed bedrock erosion to occur.” Grotzinger said that water erosion may explain flat layers on Mars. And the stratigraphy, or order and position of the layer Gale Crater, shows that there may have been a lake that supported life.

Ella Holme, a graduate student studying hydrothermal geochemistry and planetary science, said, “One of the most important things that I think someone can take away from the study of areas like Gale Crater is that you can employ traditional geologic methods to a completely alien environment and they still hold true.” This means that everything that scientists know about Gale Crater is based on the basic laws of sedimentology and stratigraphy that have been used to explain life on Earth.

Joel Hurowitz, an assistant professor in planetary geology, said “John’s research has taken him from modern rocks in the Caribbean to ancient rocks in places as close as California and as far as Africa and Australia. And as we’ve heard about today, Mars.”

The studies of Gale Crater show how similar the environment is to Earth’s and suggests that ancient Earth was similar to Earth today. Research on Mars’s geological history can help explain the evolution of life on Earth; these studies show what parts of life are present before biological processes start to impact the environment.

Justin Cowart, a graduate student studying planetary geology, said, “One goal of future Mars missions will be to explore locations where life may have gotten started, which will tell us more about the conditions where that likely happened on Earth.” Mars research will help geologists better understand how life began on Earth.

Despite Grotzinger’s historical findings, some students, especially those without any knowledge of Mars, found the lecture hard to understand. Annalisa Myer, a psychology and political science double major, said, “The speaker, although presenting on largely fascinating discoveries, didn’t seem too amazed. He also used a lot of geological jargon, which made the lecture inaccessible to students.”

But Grotzinger’s discoveries and further studies of rocks in Gale Crater will help scientists understand the type of water and minerals in Martian lakes and if the rocks were fit for life to emerge and exist.