Water on the Red Planet: There Could Have Been Flowing Rivers on Ancient Mars Formed by Heavy Rainstorms

Natural occurrences and collisions helped shaped the surface of Mars. But a recent study suggests that heavy rainfall might have shaped the surface of the red planet, too, causing rivers to appear.

This added to the theory that there was once water on Mars. Not just water, but flowing rivers. The study was published in the journal Icarus.

Based on the study, the craters on Mars changed over time after being hit by heavy rainfall. The torrential rains hit the ground, creating rivers. Scientists and geologists from the Smithsonian Institution and John Hopkins University worked on the project.

In order to come up with the findings, researchers calculated the amount of heavy rains that might have hit the surface of Mars. They incorporated the speed and weight of the raindrops and other factors such a gravity and atmospheric pressure.

The combined factors allowed them to calculate how big the raindrops are from the heavy rains that tore Mars' surface to create rivers. Based on the study, there would have been a point where the Martian atmosphere was just the right pressure to allow stormwater to erode craters and to totally change the Martian surface.

"Early on in the planet's existence, water droplets would have been very small, producing something like fog rather than rain," according to the journal.

The thicker atmosphere of Mars formed about 4.5 billion years ago. By that time, fog couldn't have caused any changes on the surface of the red planet.

An earlier study says the Martian atmosphere was lost in space. The thinner atmosphere could then cause bigger raindrops and heavier rainfalls. The water had the tendency to saturate the soil allowing channels to form into the surface causing rivers to form. And although it no longer rains on Mars, the researchers believe that the marks remain visible on the surface of the red planet.

"By using basic physical principles to understand the relationship between the atmosphere, raindrop size, and rainfall intensity, we have shown that Mars would have seen some pretty big raindrops that would have been able to make more drastic changes to the surface than the earlier fog-like droplets," Ralph Lorenz from the John Hopkins University said in the statement.

The data could also help scientists understand the changes in other planets with the same conditions.