A team of researchers used data acquired by NASA's Curiosity rover to determine that Mars once was one too many more river systems than researchers previously guessed, even going as far as to describe the Martian world as once being "a planet of rivers".

A new study published in the Geophysical Research Letters details an analysis that was conducted on data gathered by NASA's Curiosity rover, currently stationed in the Gale Crater, a prime location for looking for past river systems. The team specifically looked at erosion across the planet and applied numerical models to simulate erosion across millions of years. The team concluded that crater formations called bench-and-nose landforms are likely from remnants of ancient riverbeds.
The team combined satellite data, Curiosity's data, and 3D scans of the stratigraphy - or layers of rock, called strata, deposited over millions of years - beneath the Gulf of Mexico seafloor. All of the aforementioned data was used to train a computer model that revealed Mars could have once had far more rivers and riverbeds than previous research has indicated.
"We have everything to learn about Mars by better understanding how these river deposits can be interpreted stratigraphically, thinking about rocks today as layers of sediment deposited over time," Cardenas said. "This analysis is not snapshot, but a record of change. What we see on Mars today is the remnants of an active geologic history, not some landscape frozen in time."
"We're finding evidence that Mars was likely a planet of rivers," said Benjamin Cardenas, assistant professor of geosciences at Penn State and lead author on a new paper announcing the discovery. "We see signs of this all over the planet."
"This suggests that there could be undiscovered river deposits elsewhere on the planet, and that an even larger section of the Martian sedimentary record could have been built by rivers during a habitable period of Mars history," Cardenas said. "On Earth, river corridors are so important for life, chemical cycles, nutrient cycles and sediment cycles. Everything is pointing to these rivers behaving similarly on Mars."