Martian emptying lake formed – NRC

Most of the valleys on Mars, typical of the planet’s landscape, were created by catastrophic short-lived floods, with large amounts of water flowing to the surface. This is about a quarter of the total volume of all the valleys that formed on the young planet. Which calculated US researchers used satellite images from NASA’s Mars Exploration Orbiter. They published the results in the journal on Wednesday temper tantrums. Through this research, planetary scientists are trying to understand the early climate on Mars.

Mars is a small planet that is directly next to Earth. If we look from the Sun, Earth is the third planet and Mars is the fourth planet. Mars is about four and a half billion years old. An average temperature of -55°C makes Mars a cold desert and sandstorms sometimes blow bigger than Russia.

The surface of Mars is now dry. There is water in the form of ice and steam, but liquid water is not tolerated. Due to the low air pressure (less than one hundredth of the air pressure on Earth), water on Mars evaporates or freezes instantly.

For days to weeks, the water spreads outside the lake at lightning speed

It used to be different. Dry rivers, dotted valleys, and empty lakes the size of Earth’s tiny oceans show the abundance of water on Mars billions of years ago. The young planet at that time was much warmer than it is now and the air pressure was higher.

Although it is known that some valleys formed from lakes that overflowed their banks, according to ancient thought, the valley network on Mars generally formed gradually and slowly. For example, due to groundwater or prolonged rainfall.

Mars may have a long climate with a water cycle like on Earth: water evaporates into the atmosphere and returns to the surface through rain or snow. Prolonged and continuous rain that fell on the ground paved the way through the surface, and thus a network of valleys was said to have formed.

But American researchers have now calculated that at least a quarter of the valley network on Mars was created not gradually, but more rapidly due to overflowing lakes. Lakes, temporarily by rain or groundwater, fill and erupt on their sides. For days to weeks, water flows out of the lake at lightning speed and across the landscape, carving out a patch of land.

Topography

To perform the calculations, the researchers studied satellite images taken by the Mars Exploration Vehicle. This is a NASA satellite that has been orbiting Mars for about sixteen years. Satellite images of the topography of the valleys show whether they formed very slowly, for example due to rainfall, or because large amounts of water were flowing rapidly over the landscape as a result of overflowing lakes. “When a lake is empty due to flooding, a hole is created on its shore,” said Martin Kleinhans, a physical geographer at the University of Utrecht who was not involved in the study. “It looks like a gap, like the one created during the dam pit in Zeeland, for example. From the hole in the lake emerged a long valley that stretched far across the landscape. If a river doesn’t start from a lake, but consists of several branches like The Rhine, it’s likely to come from slow erosion.”

The researchers looked only at traces of flowing water forming on the young planet Mars and filtered out the most recent. Using an algorithm, they then calculated the total size of the two types of valleys in the satellite image. The slowly accumulating valley measures about 4.3 x 10¹³ Cubic meter. The size of the valley due to flooding is about 1.4 x 10¹³ Cubic meter. So a quarter because of flooding.

Landscapes

Planetary scientists study the valleys on Mars because they help them reconstruct what the planet’s climate should have been like billions of years ago. “The only way to do it deep in the past was to study the footprints you left on the terrain,” said Tjalling de Haas, who is also a physical geographer at the University of Utrecht and was not involved in the research. The study shows that valley formation does not necessarily require a prolonged rainy climate on Mars. However, just as on Earth, it is also true on Mars that what you see in one place should not apply in another. A prolonged elongated climate could still account for the remaining three-quarters of the valley network.”