The round and angular pebbles – some as small as a grain of sand, others as coarse as a golf ball – have been cemented together to form coarse, multi-layered stones, the U.S. Space agency nasa announced on thursday. Although previous missions to mars have detected signs of water on the red planet, these photos are the first of their kind. Scientists examined the images of the two solitary rocks in the gale crater taken by curiosity during the first 40 days after landing.
The coarseness of the pebbles suggests "that the water in the river was moving at about a meter per second and was about bone to hoof deep," said william dietrich, a researcher at the university of california who is working with others to evaluate the rover's science experiments. "This is the first time we've seen pebbles transported by water on mars. Until now, we've only speculated about the coarseness of the riverbed, now we can make observations."
The round form of the stones let conclude that the pebbles were transported by the water over a long way, communicated the nasa. "And the rough ones suggest that they have not been transported by the wind". It was water," said rebecca williams, another scientist on the curiosity mission. The rover should investigate the stones even further.
New weather data measured by "curiosity" also excited the researchers. On average, the rover measured temperatures of up to six degrees celsius in the early afternoon at mars time, scientists announced at a conference in madrid. Mars winter is much warmer than expected. "The fact that we are already seeing such high temperatures during the day is a surprise and very interesting," said felipe gomez of the center for astrobiology in madrid, according to the release. At night, however, the rover can reach much colder temperatures of up to minus seventy degrees celsius.
Mars could also be much drier than previously thought. Initial data from "curiosity" showed that the soil of the gale crater could contain significantly less than the six percent of water previously suspected, researchers explained at the conference. The water content of the soil varies on the red planet apparently very strongly depending upon region.
"Curiosity, the most expensive and technically advanced mission of its kind to date, landed on mars about two months ago to search for signs of life. The riverbed pebbles now photographed are "the assurance that we have already found our first potentially once habitable environment," said nasa manager john grotzinger.
Nevertheless, the rover will continue on to its intended research targets: first to a site on mars called glenelg and then to a high mountain in the gale crater. The "curiosity" mission is scheduled to last about two years.