Out of all the mysterious and fascinating worlds inhabiting the bewitching Wonderland that is our Solar System, the Red Planet Mars has managed to sing the most despicable of all sirens’ songs to humanity. This small, rugged, rust-colored planet is our Earth’s near neighbor in space, in addition to the world that has tantalized the imaginations of those people who seek to answer the deep question of whether or not we’re alone in the Cosmos. Nevertheless, despite its appeal, Mars has not revealed itself to be occupied, and Earth remains the only planet that is really known to host life. Of course, this doesn’t mean that life is not out there somewhere in space–it merely means that we have not as yet discovered it, and it apparently has not as yet discovered us. In July 2018, a group of astronomers announced they have found evidence that deep beneath the frigid, frozen ice cap of the Martian south pole lies a hidden lake of liquid water–the first to be found pooling on the Red Planet. Life as we know it is dependent upon the existence of liquid water.
The Italian Space Agency (ASI) led the development of the MARSIS radar. NASA contributed about 50 percent of this instrument, with direction of the U.S. part led by the agency’s Jet Propulsion Laborator (JPL) in Pasadena, California.
The research paper, authored by the Italian MARSIS group, explains how a”bright spot” was discovered in radar signals approximately a mile under the surface of the ice cap at the Planum Australe area. This powerful radar expression was determined by the study’s authors to be liquid water. This interpretation is important because where liquid water exists, life as we understand it may also exist. The presence of liquid water indicates the possibility–though by no means the guarantee –of the existence of alien life on Mars.
“The bright spot seen in the MARSIS data is an unusual feature and incredibly intriguing. It definitely warrants further study. Additional lines of evidence should be pursued to test the interpretation,” Dr. Jim Green commented in a July 25, 2018 JPL Press Release.
“We hope to use other instruments to study it further in the future,” Dr. Green added.
One of those new tools will land on Mars late in 2018. The tool, NASA’s InSight lander will take a heat probe that is designed to burrow down to the Martian surface up to 15 feet. InSight was constructed by the German Aerospace Center (DLR), and it is scheduled to present important new data concerning how much heat manages to escape from the Red Planet and in which the liquid water may pool near its surface.
The search for liquid water is currently the inspiration behind NASA’s exploration into the outer regions of our Solar System, where watery ocean-moon-worlds have the capability to host delicate life forms. Even dwarf planets, such as Ceres, the largest denizen of this Main Asteroid Belt between Mars and Jupiter, may help scientists gain a new understanding of how water is stored in rugged”buckets” that carry water throughout our Solar System.
A Hidden Lake
The hidden Martian lake is most likely extremely cold and very salty. This makes it an improbable abode for life. However, the discovery, reported for the first time on July 25, 2018, in the online edition of the journal Science, is certain to bring new hope to those scientists who seek the existence of life on distant worlds. The hunt for other buried, hidden layers of water on Mars has now intensified, and the search is on for other bodies of water on Mars that may be more hospitable to delicate living animals. “It’s a really exciting result: the first sign of a briny aquifer on Mars,” commented Dr. David Stillman at a July 25, 2018 Science Magazine Press Release. Dr. Stillman is a geophysicist in the Southwest Research Institute in Boulder, Colorado, who wasn’t part of the study.
The team of scientists think that the lake is similar to one of the interconnected pools situated several miles under the ice sheets of Antarctica and Greenland, according to Dr. Martin Siegert in the same Press Release. “It will open up a very interesting area of science on Mars,” Dr. Siegert added.
Planetary scientists generally feel that water gushed across the surface of the Red Planet billions of years ago, when it owned a warmer and warmer setting. This water is believed to have carved gullies and channels which are still visible on Mars today. However, now low atmospheric pressures imply that any surface water would boil away. By comparison, water manages to survive frozen in polar ice caps, as well as in subsurface ice deposits. Some of those ice deposits have been mapped by MARSIS.
On our own planet, microorganisms have been found swimming in the subglacial lakes of Antarctica. These hearty little germs have managed to survive in isolation from the external Antarctica for as long as 35 million years–or even longer. This is because a large number of those 400 subglacial lakes that have been discovered so far appear to be hydraulically tied to one another. Therefore, planetary scientists think it is reasonable to conclude that microorganisms may swim around almost everywhere beneath the Antarctic ice. Organisms, such as these, inhabiting regions generally considered to be inhospitable, are termed extremophiles. Extremophiles could be located on distant worlds dwelling in environments that seem to be hostile to life.
The discovery of tiny tidbits of life swimming around in the subglacial lakes of Mars could have profound significance for humanity. This is because it will be the first life to be found on a world other than Earth. In addition, discovery of these living tidbits would contribute to our scientific understanding of the incidence of life in our Solar System. Ice-covered oceans are considered to slosh around beneath the frozen shells of Jupiter’s moons Europa and Ganymede, as well as Saturn’s moons Titan and Enceladus. Additionally, Triton of Neptune, and a lot of other bodies inhabiting our Solar System’s outer limits, hauntingly whisper some tantalizing hints of subsurface liquid water seas. This indicates that the discovery of geologically persistent liquid water on so many distant planetary bodies raises the intriguing possibility that aquatic life-forms may be abundant throughout our Solar System.
The amazing Italian astronomer Galileo Galilei (1564-1642) made the first telescopic observation of Mars in 1610, with his primitive small”spyglass”, which was one of the earliest telescopes to be used for astronomical purposes. During that same century, other astronomers also observed that the polar ice caps on Mars, using the very small telescopes of that era. These early astronomers were still able to determine the Martian rotation period, as well as its axial tilt. These observations were mostly made when Mars was at its closest approach to Earth. Improved telescopes developed in the 19th century helped astronomers map permanent albedo features, and a crude map of the Red Planet was published in 1840. This very first map of Mars was followed by a series of progressively improved maps from 1877 on.
The imaginative tale of”little green men” inhabiting Mars began when astronomers mistakenly believed they had observed the spectroscopic signature of water in its atmosphere. This captivating notion of Martian life became increasingly popular with astronomers and the general public alike, and it became especially popular when the American astronomer Perceval Lowell (1855-1916) believed that he had observed a network of artificial canals carved by intelligent beings on the Martian surface. But these linear features were finally found to be only optical illusions.
Also during the 1920s, astronomers were able to determine that the atmosphere of the rusty-red world harbors only very small amounts of oxygen and water. Astronomers of that age also successfully found that the surface temperature of the Red Earth ranged from a truly freezing -121 degrees Fahrenheit to a comfortable 45 degrees Fahrenheit.
Two decades later, in 1947, the Dutch-American astronomer Gerard Kuiper (1905-1973) revealed that the thin atmosphere of Mars is composed primarily of carbon dioxide that added up to roughly double the quantity found in our own planet’s atmosphere.
Mars is the fourth planet from our Sun, and like another solid inner planets–Mercury, Venus, and Earth–it basks in the brilliant sunlight streaming out from our Star. It’s famous for its reddish hue that is caused by an abundance of iron sulfide coating its surface. In addition, the surface of Mars is scarred by a high number of impact craters that look very similar to those observed on Earth’s Moon.
Mars has a rotational period and changing seasons such as our own world. But, unlike our Earth’s large Moon (the largest moon in our Sun’s inner kingdom), Mars is orbited by a strange and intriguing duo of little potato-shaped moons. The Martian moons, dubbed Phobos and Deimos, are generally thought to be asteroids that escaped from the Main Asteroid Belt, only to be snared by the irresistible gravity of the Red Planet.
For the last two decades, cameras in orbit around Mars have sent back to Earth numerous displaying pictures. These images show that Mars sports a surface that is dotted with tiny valleys which were formed into slopes that bear an eerie resemblance in their shape to gullies that resulted from gushing floods of liquid water on our own planet. The Martian gullies are thought to be relatively young geological features that are less than a few million years old–and some can even be more young than that. A few million years isn’t a very long time on geological time scales. These more recent observations provide planetary scientists valuable clues that great quantities of life-sustaining liquid water may still be lingering on Mars, and that this water may have been responsible for carving the surface gullies.
Even though the surface of the Red Planet isn’t particularly life-friendly today, there is sufficient evidence suggesting that very long ago its climate may have been such that water in its liquid phase pooled on its surface.
Mars sports two permanent polar ice caps that are composed primarily of water ice. Frozen carbon dioxide builds up as a relatively thin layer in a pole’s Martian winter. Throughout that frigid season the poles are enshrouded in heavy blankets of relentless and continuous darkness. The extremely cold Martian winters freeze its surface, and cause the deposition of 25-30% of the atmosphere to freeze into slabs of carbon dioxide ice (dry ice). When the sticks are swept by warm sunlight during the summer and spring, the frozen carbon dioxide sublimates. These seasonal adjustments transport great quantities of water vapor and dust. This leads to Earth-like frost, in addition to large cirrus clouds. Clouds composed of water-ice were imaged by NASA’s Martian rover Opportunity in 2004.
Both Martian poles display layered features, that are termed polar-layered residue . These deposits are brought on by seasonal melting and deposition of ice together with dust from the roaring Martian dust storms that sweep over the surface of Earth. Precious information regarding the past climate of Mars may become revealed in these layers, which have been maintained in a type of deep freeze since ancient times. This has been compared to how tree ring patterns and ice core data show climate changes over the passage of years on Earth. Both of the Martian polar caps also reveal grooved features that were likely due to winds. The grooves are also affected by the quantity of dustin other words, the more dust there is, the darker the surface. It follows that the darker the surface, the more frequent the melting. Dark surfaces absorb more light. However, there are different theories which have been proposed to describe the large Martian grooves.
The south polar ice cap of Mars sports large pits, troughs and flat mesas that give it a”Swiss cheese look.” In contast, the north polar ice cap exhibits a flat surface with smaller pits than those found in the south polar ice cap–providing the north polar ice cap the appearance of”cottage cheese”, rather than”Swiss cheese.”
Hidden Liquid Water Under Ice
The radar information obtained by MARSIS provides strong evidence that there’s a pond of liquid water buried beneath layers of ice and dust from the south polar region of the Red Planet. Indeed, new evidence that Mars had an early watery past is scattered all over its surface in the kind of enormous dried-out river valley networks and vast outflow channels. These tattle-tale attributes have been clearly imaged by the spacecraft. Orbiters, along with landers and rovers, have been investigating the Martian surface for years, discovering minerals that can only form in the presence of liquid water.
Liquid water can’t exist on the Red Planet’s surface today, so astronomers are on the search for subsurface water. Scientists have long suspected that liquid water is present buried beneath the Martian polar ice caps.
The potential existence of water in its liquid phase on Mars (which may have supplied a habitable environment for delicate forms of life) was first predicted by Dr. Stephen Clifford back in 1987. Dr. Clifford’s theory was published in a paper titled Polar Basal Melting on Mars that appeared in the Journal of Geophysical Research on August 10, 1987. Dr. Clifford is a senior scientist in the Planetary Science Institute (PSI) at Tucson, Arizona.
With reference to the recent findings of ESA’s Mars Express, published in the June 25, 2018 issue of the journal Science, Dr. Clifford mentioned:”I believe that the evidence the paper’s writers have presented for the existence of liquid water at the bottom of the south polar layered deposits, in this location, is highly persuasive. It’s a finding which should be closely examined by the rest of the radar community to be sure we can rule out other alternative explanations–something I feel that the authors have already made an excellent attempt of doing.”
Whatever the degree of polar basal melting on Mars now, it was almost certainly much greater in the past, included Dr. Clifford in a July 27, 2018 PSI Press Release. Geological evidence indicates that the south polar layered deposits blanketed a region that was roughly two times as big 2 billion years ago than it is today. This means that there was much more ice about to melt. The geothermal heat flux of Mars–which results from the decay of naturally occurring radioactive elements in the crust–is also believed to have been as much as three times greater during that early time. This would have reduced the necessary thickness of polar ice for basal melting.
Dr. Clifford continued to remark:
“The job I did 30 years ago was essentially a theoretical exercise that thought what we then knew about the broad network of subglacial lakes and channels which exist at the bottom of the Antarctic and Greenland ice sheets and analyzed its possible relevance to the Martian polar caps. It’s certainly gratifying that the MARSIS radar team has found evidence that shows that this early theoretical work has some connection to reality.”