¶ … Astronomy....The subject "Life Mars: Past / Present? It 11 pages length. I attach an outline Final project paper instructions final project. I stress I NEED AN EXCELLENT RESEARCHER/WRITER FOR THIS PLEASE. The existence of life on Mars has been a topic that has continuously fascinated mankind. Mars is the planet that is closest to Earth and the only planet in the Solar System where the hypothesis of existence of life can actually be debated. All the other planets are much too hot or cold for life to be even discussed. As a consequence, a lot of research about Mars has been directed towards identifying potential traces of life, in the present or from the past, as well as analyzing the existing conditions that could make the planet habitable.

From the introductory part of this paper, there needs to be a clear understanding about the fact that life on Mars does not exist at the present, nor is there evidence that life on Mars existed at some time in the past (Conrad et al., 2013). The entire research process is currently directed towards two dimensions, with distinct correlations between them.

The first dimension refers to analyzing elements that could potentially make Mars a habitable planet. These include elements such as water or the chemical environment. An important part of the research has been focused on analyzing whether such elements existed in the past, which could be a potential argument in favor of life having existed in the past as well.

Another dimension involves searching for microorganisms that would be a clear sign of the existence of life on Mars. As shown previously, there have been no clear development and no concrete evidence in this sense so far. Because of these two dimensions, Mars is also an interesting study in terms of the origins of life. Scientists believe that conditions were similar on Earth 3.5 billion years ago, when the first signs of life appeared on Earth. As such, studying the environment and evolution on Mars could provide relevant information about how life started on Earth (McKay, 1989), answering some of the existing dilemmas.

Literature Review

Section Introduction

This literature review section will focus on the two dimensions identified in the introduction, namely on studies that analyze the existing environment on Mars, aiming to draw conclusions related to the potential habitable conditions, the other to studies that have looked into the actual existence of microorganisms and other living entities on Mars.

Review

According to Beaty D. And a group of researchers (2006), there are four large categories of factors that are used in determining habitability. These include water, the chemical environment, presence and nature of energy (for metabolism purposes) and physical conditions. Beaty develops each of these categories into subsequent elements, of which some of the most relevant ones include salinity, pH, liquid water activity (for water), nutrients and presence of toxins (chemical environment), solar and geochemical forms of energy and elements such as temperature, pressure, radiation and climate for the last category.

Other researchers have focused on past periods of time, namely on whether factors that would have led to the creation of a habitable environment existed some time in the past. This current was encouraged by the results that the NASA Curiosity Rover brought in 2013. Its analysis of rocks on the surface of Mars concluded that there may have been conditions in the past to support living organisms such as microbes (Brown, 2013). The scientists analyzed the rock sample provided by the Rover and identified several chemical elements that are essential for life, including oxygen, carbon or hydrogen.

A long discussion has been opened as to whether there is water on Mars. There are several aspects to this topic, but all scientists agree on the fact that water cannot exist in its liquid form, in the present day, on Mars. The discussions are thus focused on (1) whether water exists in solid or gas forms and (2) whether water existed, in any form, some time in the past on Martian surface.

Although water does not appear in actual form on the surface, there are particular exceptions, such as water particles formed temporarily around dust particles (Shiga, 2007). As Shiga has shown, the problem with liquid water is either that the temperature falls below freezing levels or that, when this does not happen, such as in the areas around the equator, where temperatures are occasionally above freezing levels, the low atmospheric pressure leads...

There has been some concrete evidence from exploratory missions that ice may also exist in what appears to be a crate. Other large patches of ice are locating even around the Equator. There are also glaciers present on the Martian surface.
Jakosky and Haberle (1992) have dedicated their research to the presence of water vapors in the atmosphere on Mars. Further work on water vapors in the atmosphere on Mars comes from Titov et al. (2012) mention the observations of the Imager for Mars Pathfinder (IMP), while Sanders (2011) looks into the findings of the ESA Mars Express spacecraft.

According to the latter findings, water vapors are formed as ice from the Martian poles melts and is released as vapor into the atmosphere. The combination of these water vapors and dust molecules creates cloud. However, when there is not enough dust for this to happen, the water vapors remain in a supersaturated state.

A lot of new potential for research was opened when Mariner 9 revealed, in 1971, the existence of what seemed to be valleys of rivers that formerly existed on the planet. Other forms of flowing water, including streams, led to the idea that there may have existed previously a potential for a similar type of circuit of water in nature as there is on Earth (Raeburn, 1998). Di Achille and Hynek also referred to an "Earth-like hydrologic cycle" (Di Achille, Hynek, 2010).

An article in Science Daily, published based on materials from the University of Colorado at Boulder proposed the idea that an ancient ocean may have covered as much as a third of the entire surface of the planet. The scientists analyzed the information and data regarding a series of river delta deposits and their conclusion was that as much as 29 out of a total of 52 river delta deposits may have been associated, in some way or other, to such a large Martian ocean.

This hypothesis is in no way unchallenged in the scientific community. Among many others, Carr and Head (2003) suggest that what appear as being shorelines are not. Among the potential alternatives, scientists refer to the fact that the basins may, in fact, be caused by a meteor impact or anything of significant force that would have shifted the ground in a manner that would have created a large crater.

Cabrol and Grin (2010) have looked at the existence of several lake basins on Mars. They appear to mirror what is now on Earth, including the fact that some of the river valleys are leading up to them, suggesting that, in the past, rivers flowed into the lakes. There is extensive research on the nature of these lakes, particularly on how water accumulated there.

Different schools of thought propose either the fact that they were supplied from the atmosphere, while others suggest that they were supplied from the underground. This all leads back to the theory of the existence of a natural cycle of water on Mars, similar to the one on Earth, although likely in a different form.

Di Achille and Hynek's article is also useful because of their investigation into lake deltas, an important sign of a sustained, over a longer period of time, presence of water on Mars. Di Achille and Hynek support the idea that deltas take longer to form, so their existence implies a continued water presence in a particular region.

When looking for signs of life on Mars, some researchers have focused on a wider perspective of things, namely on the potential existence of intelligent life in the Universe. Basalla (2005) has written a history of what he terms as speculation about the existence of intelligent life in the Universe, going from Plutarch to the present time. Because this work is so vast, it is useful for a study about life on Mars, giving several perspectives as to what this implies.

When man speculates about life on other planets, Mars included, he also speculates about what form this life takes: is it humanoid form? Is it different, are there different societal and group organizations etc. With Basalla's work, one does not necessarily have the answers to these questions, but a better idea about how this research continued over time, with different ideas and opinions.

Studies argue that if life forms exist on Mars, the low temperature and the ionizing radiation would only allow these forms of life to exist under the surface and in a dormant form (Lovett, 2007). Dartnell and others believe that bacteria living under the…