Mars: Life, Death, Hope? Essay, Research Paper
Venus is the 2nd closest planet to the Sun, and the closest planet to Earth. Venus can reach visual magnitudes (brightness) of -4.4, making it the brightest object in the night sky, excluding the moon. Venus was once considered Earth’s twin, a swampy place with oceans and strange creatures were imagined. After sending probes such as Mariner, Pioneer Venus, Venera (which landed on Venus), Vega, Magellan and Galileo, we know that Venus is the victim of a “run-away” greenhouse effect. Mars is the fourth planet from the Sun. If Venus is the planet with a runaway “greenhouse effect”, then Mars is the antithesis; it doesn’t have enough Carbon – Dioxide to trap enough of the Sun’s energy for water to remain in liquid form. The lack of water between these two planets seems to be one of the contributing factors to the fact that there is no life on these planets. Mars is our hope for starting colonies on other planets, so we must look at how other planets close to us developed in order to tell how Mars would develop in the future. We must also see if Mars was ever capable of having water, and even supported life in the past.
The atmosphere of Venus, which is mostly Carbon – Dioxide (98%), traps most of the Suns infrared rays, heating the surface of the planet beyond the melting point of lead. If there were oceans there, they boiled away long ago. Venus is believed to have a plate tectonic system that is much different from the plate system on Earth. Recent events have decided that if there is a plate system, most likely they are far beneath the surface or so far from our system that it is hard to call it the same type of system. Even though the plate system is far different from our own, it still circulates the crust to keep the planet changing.
The Martian surface does not show evidence of plate tectonics, so the continuous recirculating of the crust does not occur on Mars. It is believe this would have doomed Mars from the start to the thin atmosphere and desert conditions which exist on the planet today. The atmosphere is comprised mostly of Carbon – Dioxide (95%), nitrogen about 3%, argon about 1.5%, oxygen about 0.15%, and trace amounts of water vapor and other elements. Even though Mars atmosphere contains a lot of Carbon – Dioxide it is just too thin to obtain thermal equilibrium with the surface or with space to generate a warmer environment by the greenhouse effect. The Viking spacecraft which landed on Mars in 1976, tested for the presence of life in the soil of Mars, using a series of three tests. The results were mixed, but are generally accepted as negative, that life is not now present on Mars.
The Mars Pathfinder mission in September 1997 provided some evidence that Mars was once much warmer than it is today and that liquid water once flowed over its surface. Observations by Mariner spacecraft, showed the canals were a myth, and revealed the darker areas to be areas of bedrock, possibly exposed and covered by Mars powerful winds. Mars is dotted with numerous impact craters, volcanoes and ancient river beds. The presence of riverbeds and evidence of erosion due to flowing liquid water indicate that Mars once was much warmer, possibly due to volcanic activity, changes in axial tilt, or some other cause. The atmosphere that surrounds Mars today is insufficient to provide a climate warm enough for water to flow. NASA has this to say about the Martian surface
Mars and Water Mars today is too cold, with an atmosphere that is too thin, to support liquid water on its surface. Yet scientists who studied images from the Viking orbiter kept encountering features that appeared to be formed by flowing water – among them deep channels and canyons, and even features that appeared to be ancient lake shorelines. Added to this were more recent observations by Mars Pathfinder and Mars Global Surveyor, which suggested widespread flowing water in the planet’s past. Some scientists identified features which they believe appear to be carved by torrents of water with the force of 10,000 Mississippi Rivers.
There is no general agreement, however, on what form water took on the early Mars. Two competing views are currently popular in the science community. According to one theory, Mars was once much warmer and wetter, with a thicker atmosphere; it may well have boasted lakes or oceans, rivers and rain. According to the other theory, Mars was always cold, but water trapped as underground ice was periodically released when heating caused ice to melt and gush forth onto the surface. Did life arise on Mars? We do not have a definitive answer; only a direct study of the Martian soil, and rocks can answer this question. The answer may lie in the answer to the question did water ever exist on Mars. We must study things like the plate systems on Venus to help us understand how planets themselves evolve, and how it would have changed the planet Mars to the point of eliminating all life and future advancements of life on its surface. If there is water in under the surface of Mars, we may be able to access it, if we find a way to create a false greenhouse effect.
Mars, Water and Life. NASA. 3 Ocotober 2000