Today’s observations of the large valley network on Mars suggest that it is formed by flowing water. However, most climate models cannot maintain temperatures above freezing. To understand this contradiction, a team of planetary researchers modeled two main theories for the formation of temporary melting ice from precipitation (warm wet climates) or from the edge of an ice cap (icy cold climate). They found that the main difference between these scenarios is the location of the origin of the formed valley. In warm, wet environments, valleys start at various elevations. In icy, cold scenarios, the valleys only begin near elevations where the ice is melted. The authors then looked into the area of Mars, with many large valley networks focusing on the location and elevation of the Valley Head. Their findings showed that the distribution of valley heads was consistent with climate predictions that include precipitation as well as melting ice caps. This suggests that precipitation played an important role in forming these valleys, indicating that ancient Mars likely had a climate warm enough to support the rain.
Heavy rainfall may have provided many networks of valleys and waterways that formed the surface of Mars billions of years ago. Image credit: M. Kornmesser/ESO.
“We’ve seen a lot of experience in the world,” said Dr. Amanda Steckel, a researcher at California Institute of Technology.
Most scientists today agree that at least some water was present on the surface of Mars during the Noatian era, about 41 to 3.7 billion years ago.
But it has been a mystery for a long time where the water came from.
Some researchers say that ancient Mars has been warm and wet up until now, but is always cold and dry.
At that time, the young sun in the solar system was as bright as today.
The vast ice caps may have covered the highlands around the equator of Mars, and sometimes melted for a short period of time.
In a new study, Dr. Steckel and her colleagues sought to investigate warm, wet and calm theories of Mars’ past climates.
Researchers have drawn computer simulations to explore how the surface of Mars was formed billions of years ago.
They found that precipitation from snow and rain is likely to form the valley and origin patterns that still exist on Mars today.
“It’s very difficult to make any kind of conclusive statement,” Dr. Steckel said.
“But these valleys start from a wide range. It’s hard to explain that with just the ice.”
This image shows a series of ridges of a Martian river (–67.64°, 43.37°). Image credit: J. Dixon.
Today’s satellite imagery of Mars still reveals fingerprints of water on Earth.
Around the equator, for example, it can spread from Mercury’s highlands, branch out like trees, and flow into lakes and possibly into the ocean.
NASA’s patient rover, which landed on Mars in 2021, is currently exploring Jezero Crater, a site of such an ancient lake.
During the Noatian period, a powerful river emptied in the area, depositing deltas on the crater floor.
“The Atmospheric Astronomy is a major factor in the study of the University of Colorado at Boulder,” said Dr. Brian Hineck, a researcher at the Institute of Atmospheric Astronomy at the University of Colorado, Boulder.
To study its ancient past, scientists have essentially created a digital version of part of Mars.
They used software to model the evolution of landscapes of synthetic topography similar to Mars near the equator.
In some cases, they added water to the topography from reduced precipitation. Other cases involved melting the ice cap.
The simulation then lets water flow for dozens to hundreds of thousands of years.
The authors examined the resulting patterns. Specifically, we investigated the location of the origin that provided the branching valley on Mars.
The scenario produced very different planets. When melting ice caps, the heads of those valleys formed primarily at high elevations, almost around the edge of where ancient ice was sitting.
In the example of precipitation, the Martian origin was much more widespread and formed at elevations above 3,350 m (11,000 feet) high from beneath the planet’s average surface.
“The water from these ice caps begins to form valleys only around narrow elevations,” Dr. Steckel said.
“On the other hand, if you’re distributing precipitation, you can form the valley head anywhere.”
The team then compared these predictions to actual data from Mars taken by NASA’s Mars global surveyor and the Mars Odyssey spacecraft.
The simulations containing precipitation lined up more closely with the real red planet.
Researchers quickly point out that the results are not the last words about the ancient climate of Mars. In particular, it is not yet clear how the Earth stayed warm enough to support snow and rain.
“But our research offers scientists new insight into the history of another planet, our own,” Dr. Heinek said.
“When erosion from the flowing water stops, Mars will be frozen almost in time, and it appears that Earth probably went 3.5 billion years ago.”
study It was published in Journal of Journal Geophysics: Planets.
____
Amanda V. Steckel et al. 2025. Landscape evolution model of Mars incision: Ancient climate impact. jgr planet 130 (4): e2024je008637; doi: 10.1029/2024je008637
Source: www.sci.news