Images captured by NASA's Mars Global Surveyor spacecraft indicate the potential existence of liquid water on the surface of Mars, a discovery that excites scientists who are curious about the possibility of life on the Red Planet. The spacecraft's observations of changes in the walls of two craters in Mars' southern hemisphere, believed to be caused by the flow of water, were announced by a team of scientists. The presence of liquid water is crucial in the search for signs of life, as all known forms of life on Earth depend on water for survival. Scientists have previously confirmed the presence of water on Mars, in the form of ice at the poles and water vapor, as well as geological features that suggest water may have existed in the past. Kenneth Edgett, a scientist involved in the research, described the search for current evidence of liquid water on Mars as a "quest for a smoking gun," and stated that the new findings could be considered a "squirting gun" for water on Mars. The researchers, whose work is published in Science, compared images of the Martian surface taken seven years apart and identified 20 new impact craters. They observed evidence suggesting that water had flowed down two gullies in recent years, despite the harsh conditions on the planet's surface that would cause liquid water to freeze or evaporate quickly. The pictures indicated that there may be underground liquid water near the surface in some areas, which could seep out periodically. While the images did not directly show water, they revealed bright deposits left by material carried downhill inside the crater by running water, occasionally changing direction around obstacles and leaving finger-shaped marks diverting from the main flow. Edgett suggested that the water could be acidic, briny, or carrying sediment, but it definitely contains H2O. Each flow was estimated to be caused by an amount equal to "five to 10 swimming pools of water," according to Edgett. Michael Meyer, the head scientist of NASA's Mars Exploration Program, stated that recent observations indicate that water still flows sporadically on the surface of Mars, providing the most compelling evidence to date. Meyer raised questions about how this phenomenon occurs and whether it suggests a potential habitat for life. Some scientists believe that Mars may have harbored primitive life forms in the past, as it is the only planet in our solar system besides Earth with a relatively hospitable climate. Previous missions have also discovered signs that Mars had abundant water in the past. The scientists acknowledged that the images provided only circumstantial evidence, not definitive proof. They proposed an alternative explanation that the features could have been caused by the movement of dry dust down a slope. The researchers noted that their findings raised numerous questions, such as the source and abundance of the water, and whether it could be utilized as a resource in future Mars exploration missions. Although the researchers had discovered the gullies in 2000, this was the first time they had observed newly deposited material seemingly carried by liquid water. Recently, NASA announced that it had lost contact with the Mars Global Surveyor following a decade-long mission focused on mapping the planet's surface, monitoring its climate, and seeking evidence of water.