On Sept. 28, NASA unveiled new evidence that water exists on Mars. The discovery was made through images captured by the space agency’s Mars Reconnaissance Orbiter (MRO) spacecraft, which was launched in the mid-2000s to explore the red planet’s atmosphere. According to NASA Science Mission Directorate John Grunsfeld, the MRO images provide
“convincing science that validates what [the agency has] long suspected,” about the existence of water on the nearby planet.
Taken from the spacecraft’s spectrometer, the images reveal streaks along the slopes of Mars that bear the hallmarks of past flowing water. Judging from their apparent agedness and patterns, the streaks are believed to have formed during possible periods of water flow, such as when temperatures have exceeded –10 °F (Gross). The downward marks that are seen in the MRO images are referred to as recurring slope lineae (RSL).
For decades, scientists have asserted that life on Mars would be all the more possible with the presence of a water supply. As evidence mounts regarding the impacts of global warming here on Earth, some people believe that Martian colonization could be a necessity in the future.
Hydrated salt on an icy planet
Since the first Martian probe in the early 1970s, NASA has found evidence that water could possibly exist on Mars. These latest findings, however, are distinguished by the discovery of hydrated salts, which are formed by a combination of sodium chloride compounds and water molecules. The presence of salt along the RSL has raised the possibility of flowing brine during certain periods of time.
Temperatures on Mars hover around –81 °F, which is roughly 120 degrees below the average temperatures here on Earth (Gruben). Due to Mars’ colder atmosphere, science has only been able to determine the presence of ice on the red planet. However, the combination of salt and ice raises the possibility of water under certain temperatures because the mineral causes ice to melt; it’s a process applied on Earth’s roads whenever icy conditions take hold.
From the latest images of the RSL, it’s the darker streaks that are believed to be the marks of hydration. As Georgia Tech PhD Lujendra Ojha wrote in a lead report on the initial findings, the spectrometer
“found the hydrated salts only when the seasonal features were widest, which suggests that either the dark streaks themselves or a process that forms them is the source of the hydration, “ (McManus).
A history of water discoveries on Mars
Theories regarding the presence of water on Mars had long been a topic of discussion before the first attempts at reaching the red planet were undertaken via spacecraft in 1960, starting with the Soviet government’s launch of the failed Marsnik. A decade of similarly ill-fated launch attempts would follow before NASA successfully landed the Marin 9 on Mars in 1971, and the first ever surface images of Earth’s neighbor were seen by human eyes.
The chronology of spacecrafts to have successful land on Mars and reveal evidence of the planet’s natural phenomena has been as follows:
- Mariner 9 (1971–1972)
- Viking program (1975–1980)
- Mars Global Surveyor (1996–2006)
- Mars Pathfinder (1996–1997)
- Mars Odyssey (2001–present)
- Phoenix (2007–2008)
Mars Exploration Rovers
- Spirit (2003–2010)
- Opportunity (2003–present)
- Mars Reconnaissance Orbiter (2005–present)
Prior to the mid-1960s, it was believed that Mars would consist of oceans and land. Along with this theory, the planet’s darker spots were thought to be the long-distance impressions of large bodies of water. All of these theories were shattered once scientists were able to gather actual images from the red planet.
The Mariner 9 probe
Starting with the Mariner 9 space probe, scientists have gathered a more concrete set of ideas as to whether or not Mars holds water. Discoveries made during that probe included the presence of river beds and indications of water deposition, but the most significant finding was the massive Valles Marineris: a 2,500-mile canyon spread that was named in honor of the Mariner spacecraft (Redd).
The Viking probe
During the Viking space probes of the late 1970s, scientists gained a newfound understanding of the potential impacts of water across the surface of Mars. In some areas, the presence of river valleys suggested that flooding had occurred across hundreds of miles. Images collected throughout the planet’s southern half hinted at the possibility of rain. The resemblance of certain volcanic remains to flanks on the Hawaiian islands offered further evidence that Mars had experienced downpour.
The Mars Global Surveyor probe
Throughout the decade-long series of probes undertaken by the Mars Global Surveyor (MGS), various discoveries were made about the composition of minerals on Mars; all of which has provided clues as to whether the planet could have harbored water in earlier eons. In the Nili Fossae area of Mars, the MGS’ Thermal Emission Spectrometer (TES) found a high concentration of olivine: a common mineral on Earth’s subsurface that weathers into the likes of chlorite and maghemite when placed in contact with water. The presence of olivine—which is now believed to encompass at least 113,000 sq. kilometers of Mars—suggests that Mars has been an exceedingly dry planet for millions of years.
Shortly after NASA lost contact with the MGS, photographic evidence was released of two craters—Terra Sirenum and Centauri Montes—that look as though they carried water. The images date from the spacecraft’s first probe of 1999–2001 (Teles et al.)
Other discoveries made by the MGS included numerous steep-slope gullies and inner channels in places like the Nanedi Valles and Nirgal Vallis, all of which have likely contained liquid water at some point in time.
The Pathfinder probe
The short-lived Pathfinder probe of 1997 found that daily temperatures on Mars, though varied, never reached as high as 0 °C, which is the minimum point of freezing. Therefore, water could never exist in the areas where the spacecraft landed, though ice could possibly turn to water if mixed with salt.
Further observations of this probe included the possibility of past floods, which was suggested by the way that certain rocks were stacked in the Pathfinder’s viewing range. The spacecraft also captured imagery that indicated the presence of clouds and perhaps fog in the Martian atmosphere.
The Mars Odyssey probe
In 2003, the Mars Odyssey uncovered the most sizable evidence yet that water exists on the red planet. With its Gamma Ray Spectrometer (GRS), the spacecraft detected high densities of ice in both hemispheres of Mars. Numerous images captured by the GRS—which depict everything from branching valleys to apparent emptied-lake formations—have advanced the notion that Mars at one time consisted of vast bodies of water.
The Phoenix probe
In July 2008, NASA revealed that the existence of Martian water ice had been confirmed through images gathered by the Phoenix spacecraft. During a four-day excavation of the Dodo-Goldilocks trench, clusters of bright matter turned to vapor, which indicated that the clusters were in fact water ice that disintegrated upon exposure. After the probe had ended, it was reported that samples observed by the Phoenix included traces of minerals like calcium, magnesium, sodium potassium, chloride, and maybe sulfate.
Further observations during the Phoenix probe included snow, which appeared to have descended from cirrus clouds. Taking place during the Martian summer, the highest temperature recorded throughout this four-month probe was −19.6 °C.
The Mars Exploration Rover probes
NASA’s two Rover spacecrafts—Opportunity and the now-defunct Spirit—have each uncovered vast evidence that water has existed on Mars. In 2004, Spirit came across a rock named Humphrey that bore uniquely crystallized crevices, which drew scientific comparisons to the fluid-containing volcanic rocks found on Earth. The following year, Spirit encountered Paso Robles, a soil target that holds the highest density of salt thus far found on Mars. The soil was also rich in phosphorus, as was another Spirit find: the Wishtone rock. All of this salt compelled leading Rover observer Steve Squyres to suggest that water crossed the soil target (Davis).
The Mars Reconnaissance Orbiter probe
In the decade since its launch, the MRO has captured thousands of images that indicate the presence of water on Mars. The recently reported discovery of hydrated salt, which was first photographed in 2011, is only the most significant of these discoveries. In 2009, evidence of prolonged rainfall was found in the vast terrain surrounding Valles Marineris. Other images collected by the spacecraft have suggested the existence of hot springs that could possibly contain fossils.
Does life exist on Mars?
Long before the advent of spacecrafts, people had questioned the possibility of life on Mars. While probes of Mars have revealed it to be a barren, dry, and lifeless planet, each successive probe has uncovered more evidence that the planet could have once supported multi-cellular life forms.
The exploration for life on Mars began during the 1800s via telescopes, but have grown in leaps and bounds over the past four decades with landed spacecrafts. While much of the early interest in this topic centered on themes of fantasy and science fiction, photographic proof of the planet’s inner-likeness has inspired a more serious range of inquiry. Chief among the subjects that scientists now focus on for clues about the possibility of Martian life include the planet’s surface chemicals and biospheric gases.
As a basis of study regarding life’s origins, one of the most interesting prospects regarding Mars is the planet’s resemblance to the early, prehistoric Earth. As a much colder planet, devoid of factors like continental drift or plate tectonics, Mars has seen little change over the past 30 million years. Though there has been no absolute proof as to whether life does or doesn’t exist on Mars—either now or at any time in the past—the planet’s 3.5-billion-year old surface is viewed by scientists as a potential goldmine for prebiotic study.
“NASA Confirms Evidence That Liquid Water Flows on Today’s Mars.” NASA.org. NASA. 28 Sept. 2015. Web. 6 Oct. 2015.
Gross, Paul. “Breaking news from NASA: Water exists on Mars.” Click On Detroit. Graham Media Group. 28 Sept. 2015. Web. 6 Oct. 2015.
Gruben, Mallory. “Liquid Water on Mars.” HC Media Online. Gray Center for the Communication Arts. 7 Oct. 2015. Web. 7 Oct. 2015.
McManus, Dustin. “Evidence of Liquidized Water Has Been Found on Mars.” The Toggle. Striking Inc. n.d. Web. 6 Oct. 2015.
Redd, Nola Taylor. “Valles Marineris: Facts About the Grand Canyon of Mars.” Space.com. Imaginova Corp. 29 March. 2013. Web. 7 Oct. 2015.
Teles, Antonio de Morais M. “Mars Astrobiology: Recent Status and Progress.” Planetary Exploration and Science: Recent Results and Advances. Ed. Jin, Shuanggen; Nader Haghighipour; and Wing-Huen Ip. Springer: New York City, 2015. 172. Print.
Davis, Mark. “Man On a Mission.” NOVA. Public Broadcasting Service. n.d. Web. 6 Oct. 2015.