MAVEN probe sends first results on loss of atmosphere on Mars

2015/11/05 Agirre Ruiz de Arkaute, Aitziber - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Astronomia

The MAVEN space probe was sent to research into the atmosphere of Mars in 2013 and since its arrival in September 2014 they have published their first results today. The goal of the probe was to clarify why the planet Mars is dry and almost without atmosphere. And it seems that at one time Mars was a humid and temperate planet, unlike what happens now. The explanation for this climate change is found in the atmosphere of Mars, where the current atmosphere is really fine (about 1% of the Earth's atmosphere). The atmosphere is responsible for the heat not escaping from the planets, and the refinement of the atmosphere of Mars may be behind this climate change.

The results of MAVEN have supported this hypothesis and have indicated the Sun as responsible for it. Although it seems quiet, sometimes the solar wind comes out at a speed of 500-1000 km/s. In fact, NASA researchers have taken advantage of one of these violent storms of wind and, upon reaching Mars, have discovered that it rips the atmosphere from the red planet. The atmosphere has suffered a significant loss of gases.

On March 8 there was a giant explosion of gas and magnetism in the Sun. At that time, MAVEN was measuring the magnetic field of Mars and they saw the Sun's storm spinning and ejecting that magnetic field from Mars, winding in the form of a rope, moving into space up to 5,000 kilometers. Also the devices measuring atmospheric ionization measured large peaks, since the ions are ejected into space, concentrated around these types of rope and 10 times faster than normal.

At the same time, when MAVEN has studied the upper atmosphere, ionosphere and magnetosphere of Mars, they have discovered that there is a large temperature gradient. In addition, carbon dioxide, argon and nitrogen dioxide have been detected, with a higher oxygen content than expected. Gas density has also been shown to be variable in orbit. According to the researchers, it is due to the magnetic field caused by the solar wind and, to a lesser extent, to the terrestrial surface of Mars, the gradients seen in the magnetic field and in the ions.

Mars now has no atmospheric pressure like Earth, nor a global magnetic field. Therefore, when the solar wind sounds, it has been shown to extract the atmosphere from Mars with the results of the MAVEN probe. They want to measure the speed at which that atmosphere is spent and, as far as possible, back 4,000 years ago and extrapolate if at that time Mars had more atmosphere. In fact, the demonstration that the solar storm causes a great loss of ions and its usual character leads NASA researchers to conclude that in the early history of Mars a great atmospheric loss could occur.

Scientists are increasingly clear that at some time there was water on Mars. The craters we see now are lakes. The dry, cold desert we now see was full of wet valleys. Due to the low current atmosphere of Mars, there is no atmospheric pressure that, like on Earth, produces the presence of water on the surface -the pressure of Mars is 7 millibar, while that of Earth is 1.013 millibes-. However, it is believed that in its day it had a closed atmosphere of carbon dioxide. NASA believes that the existence of a vibrant atmosphere can cause water to be present on the surface.