A Scientific Report: Possibility Of Life On The Red Planet

Introduction

54. 6 million kilometers away from the Earth, named after the roman god of war and often called the “Red Planet”, is a planet that has drawn attention from scientists and civilians alike. Mars is the 4th planet from the sun (1. 52 AU), the second smallest planet in the solar system after Mercury, with 2 of its own satellites named phopos and deimos. Its overall density is less than Earth’s, and it is about half the size with its diameter being 6, 792. This planet is particularly interesting to scientists. Its history holds a long story of belief and disbelief.

In the 1800’s, scientists believed that because Mars’ surface seemed to be changing over time, it must have an atmosphere like Earth’s. They believed they saw seasons in the growth and recession of white polar caps at both poles of the planet. By the 1900’s society became obsessed with the idea of alien life on mars even though many scientists doubted this from the images that were received by the US Mariner 4. In 1971 the Mariner 9 showed there was clear evidence of erosion, forming small river systems and even large floods on its surface, meaning there was clearly liquid water at some point. This was a huge revelation that led even greater ideas for possibility of past life on mars

Scientists began to look for more life, and in doing this, the definition of life comes in question. Biologists can have a very different definition than a theoretical physicist, however many definitions overlap in purposeful ways. For the purpose of this essay, we will define life by the information provided by NASA database. Living things are complex and highly organized, have the ability to take energy in from the environment and transform it for growth and reproduction, living things have a tendency for homeostasis, have response and ability to learn, reproduction is necessary for evolution and natural selection, be a consumer. According to NASA, to qualify as a living thing you must meet some variation of this criteria. On our living earth: carbon-based chemistries, dependencies on water, and leaving behind fossils with carbon or sulfur isotopes that are evidence for metabolism are the main qualities of a living thing.

Rules for Life

With qualities of living things comes the question of what a habitat must have to support and sustain life. Carbon is an extremely important characteristic of a living habitat. It is the basis of all life on Earth in its unique ability to form a huge variety of molecules and essentially – life. The crust of such a planet needs to be constantly recycled to keep carbon dioxide levels from getting too high or low. When levels are too high, they act as a greenhouse gas that heats up the planet, evaporating water and drying it up. In other words, resurfacing is necessary to balance the climate. This happens on earth with our mobile surface through tectonic plates releasing energy from below the surface. Another important characteristic are liquid solvents. These are important for life forms to be able to move and adapt which were stated prior as important features of living things. Therefore, water is also a likely requirement for life forms to exist. A third important feature that a planet must possess to be habitable is its location. More specifically, it must be in the “habitable zone” of a star. This is the region around a star in which liquid can form, exist, and remain liquid long enough to support life. Earth, of course, is in this zone and so is Mars. A planet as such must always not be facing the sun with the same face, making gravitational pull and orbital cycle extremely important. Another important value for life’s existence is having atmosphere to protect its surface from lethal UV radiation and extreme impacts that would wipe out all life forms.

Mars does meet some of these requirements and likely has met others of them in the past. For example, resurfacing is evident on the Red Planet. Over 635, 000 impact craters have been observed and used for relative aging. In simplest terms, the more craters in a certain region, the older it is said to be. It appears that in some parts of mars were formed at the end of the Heavy Bombardment period in the last stages of planet building. In other areas, however, resurfacing appears to have occurred no more than a few hundred million years ago. Evidence of resurfacing is a huge importance in determining whether life can exist, proving that carbon dioxide levels were attempted to be balanced. Despite it’s attempts, unfortunately, almost all of its carbon dioxide was used up to form carbonate rocks, and without plate tectonics the carbon dioxide was unable to be recycled to sustain the greenhouse effect ultimately making the surface much colder. Leftover is a thin atmosphere composed mostly of carbon dioxide, and then nitrogen, argon, and traces of oxygen and water. This small greenhouse effect only raises the surface temperature by about 5 degrees. Even though these facts tell us the surface is cold, in 1971 the Mariner 9 brought back evidence of huge, hot volcanoes that have also been found on Mars. Like Earth’s volcanoes, they have gentle sloping flanks and craters that act as magma reservoirs. These craters, called caldera, could be the answer to how life forms could exist in a freezing world. No Martian volcano eruptions have occurred in our lifetimes; however, evidence also suggests that some of these volcanoes are not dead- just in the dormant phase of their eruption cycle.

With given climate conditions, it is apparent that liquid water is unable to exist in the current state of Mars. Atmospheric pressure is too low to keep it from boiling away to water vapour. However, this is not to say that water has not existed in the past. In 2006, the Mars Orbiter Camera on the MGS showed High-Res images of polar caps in the form of dry ice at the north and south poles, giving increasing interest in the probability of water on mars. These ice caps grow and recede throughout the planet’s orbit giving scientists good reasons to believe in a seasonal cycle occurring. Another major clue that water existed in the past on mars is the finding of deuterium- a heavy isotope of hydrogen- in the atmosphere. This highly suggests that abundant amounts of liquid water covered mars. Clearly, it is possible that conditions on Mars in the past could have been enough to sustain life. By doing analogue studies that replicate Martian conditions here on earth, it is easier to understand how exactly this could have happened and what combinations of environmental factors would make life viable.

Analogue Studies

In Northeastern Scotland, the Orcadian Basin has been a popular site for analogue studies, being a comparable size and structure of the massive Mars Gale Crater. 6 Both have long histories and comparable sedimentation with sulphate rich minerals. The basin demonstrates that hydrothermal systems could develop in a lacustrine basin, circulating fluid and nutrients during sedimentation to keep microbial organisms alive. On mars, subsidence like this is not continuous however, in a similar manner the thermal afterglow of crater impacts drives hydrothermal activity in craters on mars as it has on earth. Further in this study, Orcadian injected sandstone structure gave stratigraphy like injected mars gale crater. These injected structures defy the gravitational instability, make conduits for fluid flow and have high surface area of sand-stone/mudstone interface (making them good habitats). The distribution of sulphide minerals in the Orcadian Basin indicates several settings where subsurface biological activity could have occurred, and which can be tested by isotopic analysis. Overall this study proved that despite harsh atmospheric conditions, there could be opportunity for life beneath the surface.

Another analogue study performed in Southwestern Spain, Rio Tinto gave way to understanding how life could persist through localized protected environments on mars. The Rio Tinto is an extremely acidic environment, with high concentration of ferric iron and sulfates, products of the “metabolism of pyrite, generate a collection of minerals, mainly gypsum, jarosite, goethite and hematites, all of which have been detected in different regions of Mars. ” This study found a conclusion that the stability in pH and temperature seems to indicate a microbial adapted protected ecosystems what was confirmed when spectral analysis outside and inside the salts deposits were took. The localization of those protected micro niches inside salts deposits in such Earth analog suppose an important step forward in the habitability potential of Mars surface. This is significant for possibilities of future life on mars in that protected micro niches like this could be established by microbes on the surface of Mars on areas were salty deposits have been identified. These salty crusts would protect life from radiation harm.

Conclusion

In conclusion, the possibility of past life on mars is plausible. Life forms take many, from tiny single celled organisms to walking and talking extraterrestrial life. Due to the harsh conditions we see on Mars including the thin atmosphere and temperature extremities, and lack of liquid water; scientists stand sure that life does not currently exist on mars. In turn, the question at hand is whether it did in the past, and if so, how? And can it happen again in the future? The best way to research these questions without great time and expense are with analogue studies on earth. This is an important building block in preparation for missions, and in forming basis’s for new hypothesis. Analogue studies that have been conducted so far tell us that life is extremely resilient and under certain conditions can indeed survive. This is a major revelation and opens the door for creativity and imagination in future missions and new discoveries to be made about the possibility of life inside of our solar system and beyond.