NASA's Mars Global Surveyor spacecraft captured compelling images indicating the possible existence of liquid water on the Martian surface, a discovery that excites scientists curious about the potential for life on the Red Planet. By observing changes in the walls of two craters in Mars' southern hemisphere, scientists using the US spacecraft have detected evidence of water flow in recent years. This finding contributes to the ongoing question of whether life could have thrived on Mars, as water is essential for all known forms of life on Earth. Researchers previously confirmed the presence of water in various forms on Mars, such as ice at the poles and water vapor, as well as geological features suggested to have been shaped by water in the past. Kenneth Edgett, a scientist from Malin Space Science Systems in San Diego, described the search for concrete evidence of liquid water on Mars as a quest for a "smoking gun". He referred to their recent findings as a "squirting gun" for water on Mars. The team of scientists, whose study is published in the journal Science, analyzed images of Mars taken seven years apart and identified 20 new craters caused by space debris impacts. They observed evidence of water flowing down two gullies in recent years, despite the fact that liquid water cannot persist for long on Mars' cold and nearly airless surface due to rapid freezing or evaporation. The evidence suggested that there may be underground liquid water close to the surface in certain areas, which could seep out periodically. The images did not show water directly, but they displayed bright deposits left by material carried downhill inside the crater by running water, occasionally meandering around obstacles and leaving finger-shaped marks diverting from the main flow. Edgett mentioned that the water involved could be acidic, briny, or carrying various sediments, but it definitely contained H2O. He also noted that each apparent flow was caused by an amount equivalent to "five to 10 swimming pools of water." Michael Meyer, the head scientist of NASA's Mars Exploration Program, stated that recent observations suggest that water still flows occasionally on the surface of Mars, providing the strongest evidence to date. He posed questions about how this phenomenon occurs and whether it could indicate a potential habitat for life. Mars is considered to have a less hospitable climate compared to Earth, but some scientists believe that it may have supported primitive, bacteria-like organisms in the past. Previous missions have found evidence suggesting that Mars had abundant water at one point in time. The scientists acknowledged that the images provided only indirect evidence and not definitive proof. They mentioned a potential alternative explanation that the features could have been created by dry dust moving down a slope. The researchers noted that their discoveries raised several questions, such as the origin and quantity of the water and whether it could be used as a resource in future Mars missions. They first observed the gullies in 2000, but this was the first time they observed recently deposited material that appeared to have been carried by liquid water. Recently, NASA announced the end of communication with the Mars Global Surveyor following a successful mission that lasted a decade and involved mapping the planet's surface, monitoring its climate, and searching for signs of water.