Nasa\u2019s Curiosity rover has detected organic molecules on Mars, including chemicals widely considered building blocks for the origin of life on Earth.<\/p>\n
Five of the seven molecules identified in a dried lakebed near the equator had never previously been observed on the red planet. The analysis performed by the robotic rover cannot establish whether the organic compounds are linked to potential ancient life on Mars<\/a> or were delivered by meteorites or formed through geological processes. However, the finding implies that if microbial life once thrived on Mars, chemical fingerprints should remain there today.<\/p>\n \u201cWe think we\u2019re looking at organic matter that\u2019s been preserved on Mars for 3.5bn years,\u201d said Prof Amy Williams, an astrogeologist at the University of Florida and a Curiosity mission scientist, who led the experiment. \u201cIs it life? We can\u2019t tell, based on this information.\u201d<\/p>\n The car-sized Curiosity rover has been wheeling around the Gale crater and Mount Sharp since the robot descended on to the planet in 2012. Surface conditions are harsh, with temperatures dropping to below -100C at night and the lack of an atmosphere meaning Mars is blasted by powerful radiation from the sun. But in the distant past liquid water flowed on the surface and Mars had an atmosphere that protected it from radiation.<\/p>\n \u201cIt had all the conditions for life to start there when life was starting on Earth,\u201d said Prof Andrew Coates, a planetary scientist at University College London\u2019s Mullard Space<\/a> Science Laboratory, who was not involved in the latest findings. \u201cThere\u2019s no known reason why it shouldn\u2019t have started on Mars as well.\u201d<\/p>\n However, scientists have been unsure whether the chemical traces of life from this window of habitability, about 3.7bn to 4.1bn years ago, would have survived to the present day.<\/p>\n Williams said: \u201cFor a long time, we thought that all organic matter was going to be seriously degraded by that harsh radiation environment. It\u2019s really exciting to see [that] large complex material can survive in the subsurface environment.\u201d<\/p>\n The rover recently used its onboard analysis instruments to search for and detect compounds including carbon that are linked to life. The rover identified benzothiophene, a sulphurous chemical often delivered to planets by meteorites. And the experiment hinted at the presence of another nitrogen-bearing organic compound that bears a structure similar to precursors to DNA.<\/p>\n \u201cThere are several steps between what we found and DNA,\u201d Williams said. \u201cIt is definitely a building block to how DNA is made now. But it is truly just the bricks, not the house. You can generate these molecules geologically.<\/p>\n \u201cThe same stuff that rained down on Mars from meteorites is what rained down on Earth, and it probably provided the building blocks for life as we know it on our planet,\u201d she added.<\/p>\n The findings add to hopes that the European Space Agency\u2019s delayed Rosalind Franklin mission<\/a>, which is scheduled to launch in 2028, could provide more detailed evidence about the nature of organic chemicals on Mars. The rover will drill to a depth of 2 metres and will be equipped to perform more sophisticated tests aimed at assessing the origin of such compounds.<\/p>\n