The Curiosity Rover has been NASA's tool in understanding the potential habitability of Mars in the planet's ancient past. It drilled deep into its rocks and studied their dust in order to determine the possibility of life on Mars.
Intriguing clues have been discovered by Curiosity's efforts, and scientists now follow up the clues and pieces of the puzzle to come up with a thorough understanding. The Curiosity Rover in 2018 finally located organic matter in the soil samples of the 3 billion-year-old mudstone, located in Mars' Gale crater.
Sites were sampled by Curiosity by drilling down five centimeters below Gale crater's surface. This is the area where Curiosity landed last 2012. It is a 96-mile crater that was named after Walter F. Gale, an Australian astronomer. The crater is speculated to have been formed by a meteor impact sometime between three and a half to 3.8 billion years ago. It includes Mount Sharp, and it also likely had a lake in the past.
The organic molecules within the rocks were examined by heating the samples at a rate between 932-1,508°F. This released the molecules, after which the gas was analyzed. The scientists found that the volatiles and organic molecules were composed of dimethylsulfide, methanethiol, methylthiophenes, and thiophenes.
Scientists believe these are the fragments of larger molecules which used to be present on the planet billions of years in the past. They think that the samples' high sulfur content may have preserved them. Researchers are now investigating thiophenes, which are organic compounds that are found in crude oil and coal to try to determine their origin. These compounds may be indicators of the presence of life. Thiophenes may be a sign of a biological process that involves bacteria.
Scientists think that a number of biological pathways that produce thiophenes are more likely to occur than chemical pathways. This was revealed by study author Dirk Schulze‑Makuch, an astrobiologist of the Washington State University. The other details of the study can be found here. Schulze‑Makuch further stated that thiophenes back here on Earth are thought to be biological; this does not prove, however, that the same is true on Mars.
Thiophene molecules are organized as a ring that includes a sulfur atom plus four carbon atoms, and these are considered biologically essential elements. They may be the creation or by-products of bacterial processes. Still, the thiopenes on Mars may have come from crashing meteors or high-temperature reactions between hydrocarbons and sulfates, and do not indicate ancient life at all.
The building blocks of life on Earth include organic molecules and compounds, although they may not be true elsewhere; they can also be present even when no life is there. Organic matter may mean that there has indeed been ancient life; or it may be a record of that life's food source; or finally, that something exists in place of life. They may indicate things other than life's presence.
The data is still inconclusive. Other rovers such as the Rosalind Franklin rover and the Perseverance rover are due to visit and collect more samples soon, particularly fossils as well as other indicators of ancient life. But scientists think that it may take a man to physically go to Mars to really be sure. In the end, an astronaut may be needed to just go there, scoop out a sample, put it into a microscope, and see a living microorganism swimming on his slide.