Mars was full of liquid water; Mars never had liquid water. It’s an ever changing theory with no end in sight. Back in May of this year, I wrote an article on how astronomers found the first evidence of a river that once flowed for more than 100,000 years on the Red Planet. That study strongly suggested that around 3.7 billion years ago, the planet would have had an atmosphere that supported large amounts of liquid water and perhaps even life. (The article can be read here.)
Now, scientists have changed their tune again as they’re saying that Mars may not have been the warm, wet, potentially habitable planet that they once thought was possible. Experts analyzed information from the Mars Orbiter Laser Altimeter on NASA’s Mars Global Surveyor spacecraft that collected data from 1997 to 2001. They studied over 10,000 valleys on the Red Planet in order to find out what it looked like during its first billion years of existence. They compared their Martian data to Devon Island in the Arctic and they found that the valleys on Mars could have been created in a similar way to those found below the island here on Earth.
Anna Grau Galofre, who is a geophysicist at Arizona State University and the lead author of the study, said in a statement, “If you look at Earth from a satellite, you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape,” adding, “Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them.”
They found that the majority of the valleys on Mars had a better chance of being formed by melt-water that flowed between an ice sheet and the ground instead of by a flowing river on the surface.
They studied six characteristics from each of the 10,000+ valley segments and then compared them to four types of formations. Their results indicated that 22 of 66 valleys were created by melt-water that ran underneath glaciers; 9 others were formed by only glaciers; and 14 were created by rivers. The rest of them didn’t have enough information in order for scientists to make a conclusion on how they were formed. Another interesting fact was that while the valleys that could have been created by melt-water were located in different areas across the planet, the ones that may have been formed by flowing rivers were in one specific area close to Arabia Terra.
“For the last 40 years, since Mars' valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys,” Grau Galofre stated, adding, “We tried to put everything together and bring up a hypothesis that hadn't really been considered.”
With this new research, it seems as though Mars may not have been full of liquid water and may have been covered mostly in ice. The mystery and uncertainty about the atmosphere and temperatures on ancient Mars continues...