NASA Mars Explorer Curiosity captured this image on January 2, 2018, using its Mars Hand Lens Imager. The tubular structures were probably created by crystal growth, said the mission team members.
Credit: NASA / JPL-Caltech / MSSS
If you heard NASA's Mars Curiosity Explorer has just detected signs of life on the Red Planet – well, do not get excited.
The strange tubular structures that Curiosity has been investigating lately were probably formed by crystal growth, not small digging creatures, mission team members said.
"When we look at these things closely, they are linear, but they are not tubular in the sense of being cylinders, they are actually quite angular," said Curiosity mission scientist Ashwin Vasavada of NASA's Jet Propulsion Laboratory at Pasadena, California [The Search for Life on Mars (A Photo Timeline)]
"They have a kind of square or parallelogram cross-section and they are formed in angles when there are several together," he told Space.com. "And all that reminds a lot of crystal growth."
Curiosity's team suspects that the characteristics of the tube are in themselves crystals, or that the crystals formed a mold in the rock that was then filled by sedimentary material, Vasavada added. Both scenarios involve liquid water, which suggests that the area that Curiosity is currently exploring was wet long ago.
That area is the flank of the imposing Mount Sharp, more than 1,000 vertical feet (300 meters) above the landing site of the rover on the floor of Gale Crater.
Curiosity has already found abundant evidence of groundwater and an ancient system of lakes and streams in the crater floor and in the lower foothills of the mountain. The mission team suspects that the Mount Sharp rocks harbor evidence of Mars's transformation from a relatively warm and humid world to the cold, dry planet it is today, but Curiosity will have to keep climbing to find that transition zone.
& # 39; Already reached the dry part of Mount Sharp & # 39; said Vasavada.
Curiosity has been scrutinizing the strange structures with two different science instruments: the Laser ChemCam and the Alpha Particle X-ray Spectrometer (APXS) in an attempt to guess its composition. But tubes are difficult targets; Although they are important in the enlarged photos of Curiosity, the characteristics are only 1 millimeter wide by 5 millimeters long.
"They are rice grains," said Vasavada.
The results of ChemCam and APXS should be known within the next week, he added.
Despite all the above reasoning, the mission team has not ruled out the possibility that the new features of the tube have been carved by Martian life forms. Rather, it simply is not the most likely scenario, given the available evidence.
Furthermore, it is notoriously difficult to prove that the sedimentary structures here on Earth are fossils in good faith, said Vasavada, so making that case on Mars would be especially difficult, even if it were true.
"Unfortunately, we may not have the ability with Curiosity to say that," he said.