New river flow analysis technique shows the possibility of life on Mars
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Dirty tracks and craters are all that remain of the ancient rivers and lakes on Mars, while rivers of liquid methane still flow on Saturn’s largest moon, Titan, today.
While scientists have observed evidence of rivers in other worlds in our solar system in the past, until now, they have struggled to study them in any great depth.
However, geologists at Massachusetts Institute of Technology (MIT) have recently developed a new technique that paves the way for scientists to measure the intensity of river flow on other planets, exoplanets and moons.
MIT says that the new method uses satellite observations to estimate the rate at which rivers move fluid and sediment downstream.
Researchers have used satellite data and adopted equations from Earth to calculate the flow rates and attributes of these rivers.
Despite not being able to study the rivers in person, the new technique has helped scientists make predictions about the rivers’ behavior.
Taylor Perron, the Cecil and Ida Green Professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS) said: “What’s exciting about Titan is that it’s active. With this technique, we have a method to make real predictions for a place where we won’t get more data for a long time,”
“And on Mars, it gives us a time machine, to take the rivers that are dead now and get a sense of what they were like when they were actively flowing,” added Perron.
Remote satellite data
The data from NASA’s Cassini spacecraft has provided a more limited number of images of Titan’s surface than those of Mars, due to the moon’s thick atmosphere and distance from Earth.
When studying the river images taken, MIT researchers were perplexed by the lack of fan-shaped deltas at the mouths of Titan's rivers, unlike rivers on Earth.
MIT notes that the team based their hypothesis on the work of Gary Parker, also co-author of the study. He developed a series of mathematical equations to describe river flow on Earth in the 2000s.
The research expanded on Parker’s theory which found that there were certain universal relationships between a river’s physical dimensions including its width, depth, slope and the rate at which it flowed.
The scientist analyzed the situation mathematically by drawing up equations with variables like gravitational field strength on the river, and the size and density of the sediment pushed along the river’s bed.
Perron says, “This means that rivers with different gravity and materials should follow similar relationships. That opened up a possibility to apply this to other planets too.”
Earth-like rivers
First author of the study, Samuel Birch developed Parker’s equations with some algebraic tinkering which works with just the width and slope inputs.
Birch tested the new equations on the data from 491 rivers on Earth and found that the predictions based solely on each river’s width and slope were accurate.
The modified equations were then applied to ancient rivers on Mars, specifically, those leading into Gale and Jezero Craters, which were once water-filled lakes billions of years ago.
According to MIT, Birch used the equations of Mars’ gravity, and estimates of each river’s width and slope, based on images and elevation measurements taken by orbiting satellites, to predict the flow rate of each river.
Scientists determined that rivers likely flowed for at least 100,000 years at Gale Crater and at least a million years at Jezero Crater, long enough to possibly support life.
The research estimated data from two delta-less rivers on Titan and compared them to one of the biggest rivers on Earth – the Mississippi River.
They found that due to the lack of movement in depositing sediments, the deltas were unable to form on Titan.
The study also calculated that rivers on Titan are wider and have gentler slopes compared to rivers carrying the same flow on Earth or Mars.
“Titan is the most Earth-like place. We’ve only gotten a glimpse of it. There’s so much more that we know is down there, and this remote technique is pushing us a little closer,” Birch said.
The study was published yesterday in the Proceedings of the National Academy of Sciences.
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