With the help of neutrons, the Mars laboratory Curiosity can measure the water concentration in the soil. © Russian Federal Space Agency / NASA.JPL-Caltech
Read aloud In the underground of the Gale crater on Mars is much less water than previously thought. Measurements from orbit had suggested that the soil contained about six percent water. "Preliminary results from Curiosity, however, show only a fraction of it, " reported astronomer Maxim Mokrousov at the European Planet Congress in Madrid. Further measurements show that it is not only dry at the landing site of the rover, but also unusually warm for Mars. Although spring is just beginning, temperatures are already climbing regularly to plus levels, according to Felipe Gómez from the Center for Astrobiology in Madrid. "Measuring temperatures during the day is a surprise, " said Gómez. "If the trend continues, we could anticipate temperatures over 20 degrees in the summer." During the day it could then be warm enough on a regular basis that liquid water can form. However, the observation period is still too short to dare a reliable prognosis.

In addition, water seems to be scarcer underground than expected, as shown by the results of the DAN (Dynamic Albedo of Neutrons) instrument. This instrument shoots neutrons into the ground to measure the concentration of hydrogen atoms that are believed to be bound in water molecules. One explanation for the unexpectedly low water concentration that has now been found could be that the water is distributed more unevenly in the crater than assumed. The previous values ​​are based on measurements from orbit, which are averaged over an area of ​​90, 000 square kilometers. The first measurements of Curiosity already indicate that the values ​​vary strongly locally.

At least in the distant past, the crater Gale was really wet, the US space agency NASA announced last week. Photographs of river pebbles clearly show that once upon a time larger bodies of water poured into the crater. "From the size of the pebbles, we can conclude that the water was moving at a speed of about one meter per second and was waist-deep, " said William Dietrich of the University of California at Berkeley.

The roundish shape of many pebbles in the photographed conglomerate shows that water transport persisted for a long time. This is the first living environment found, said project scientist John Grotzinger of the California Institute of Technology in Pasadena. Curiosity is now to measure the frequency of certain chemical elements in the fine-grained matrix in which the pebbles are stuck. Thus, the Curiosity team wants to characterize the environment in which the stones deposited, more accurately. display

M. Litvak, I. Mitrofanov (Space Research Institute, Moscow, Russia): EPSC Abstracts, Vol. 7, EPSC2012-346 European Planetary Science Congress 2012 © science.de - Ute Kehse

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