Definition
Mars is the fourth planet from the Sun in our Solar System.
Basics
Mars is named after the mythological Roman god of war because it is a red planet, and red is the colour of blood.
Mars has two very small moons, called Phobos and Deimos. The planet Mars is made of rock. The ground there is red because of iron oxide (rust) in the rocks and dust. The planet has a small carbon dioxide atmosphere. The temperatures on Mars are colder than on Earth, because it is farther away from the Sun. There is some ice at the north and south poles of Mars, and also frozen carbon dioxide. Mars does not have any water on the surface now, except at the poles, but most scientists think it used to have water.
The average thickness of the planet's crust is about 50 km (31 mi), with a maximum thickness of 125 km (78 mi). Earth's crust, on average 40 km (25 mi), is three times smaller as Mars’ crust based to the sizes of the two planets if they are made equal.
Mars has been known since old times. The Greeks named this planet Ares, after their god of war, but when the Romans took over the Greeks, they named the planet Mars.
Some of the first attempts at mapping Mars were done by Giovanni Schiaparelli. What he saw through his telescope confused him. He saw what he called canali, which were ditches dug for water to pass through. This started a rumor that there were other animals and life on Mars, possibly even aliens. Today, we know there cannot be any such aliens.This is because the crafts sent to Mars have detected no trace of alien life, and what could have been bacteria were formed at temperatures too high for life to exist.
Life on Mars? Because Mars is the closest planet to Earth in the Solar System, some people have wondered if there is any kind of life on Mars. Recently, scientists found an old meteorite that had landed near the Earth's south pole and decided it had come from Mars. In the meteorite they found some very tiny little shapes in the rock which they think might be fossils made by living things. However, they were not sure if it was life or just the natural patterns of the rock. If it were the fossils of a living thing, it was probably some simple plant, and hundred of them could fit across the width of a single hair.
It is also possible that there are also pieces of the earth on Mars. If a giant meteorite hit the Earth, the force would be strong enough to send pieces of the earth up to space. Creation scientists think that if anyone ever finds signs of life on Mars, it will not be Martian life they find, but earth life that made it to Mars! If a piece of earth left the atmosphere, it would take along with it lots of cells and bacteria, which are living things.
Martian Rotation Mars rotates in 25 hours, only 1 more hour than Earth. It rotates on a tilt, just like the Earth does, so it has four different seasons. However, these seasons are quite different from the ones we have on Earth! Winter, spring, fall, and summer would all be freezing cold—because it is always freezing on Mars! It's just too far away from the son to get enough energy from the sun's light, and the atmosphere is much too thin to keep the warmth inside. The usual temperature on Mars is usually about 81 degrees below zero, and in the summer, the temperature goes up about 32 degrees. Because it is so cold on Mars, carbon dioxide freezes in the winter and makes a lot of dry ice.
On earth, there is a lot of liquid water, but people have not found any liquid water on Mars. Scientists think that all of the water on Mars is frozen. The summer in Mars is warm enough to get rid of the dry ice, but it is not warm enough to melt the ice that is made of water. Scientists think that the rest of the water on Mars is permanently frozen in the ground (permanently frozen ice is called permafrost, so there's a lot of permafrost in Mars!). However, Opportunity rover has found a rock formation on Mars which suggests that the rocks might have been in salt water once. The Spirit rover also found traces of a mineral called jarosite, which is made in liquid water. So there is some evidence that liquid water did, once, exist on Mars (this means that Mars must have been much warmer long ago).
Even though Mars is really cold, it's actually closer to the Earth's temperature than any other planet in the Solar System. This is the reason lots of people think of sending humans to Mars one day, and dream of building an artificial ecosystem that will protect people.
Martian Atmosphere Mars has a very thin atmosphere with no oxygen (it is mostly carbon dioxide). Of course, since there is an atmosphere, however thin it is, the sky does change colors when the sun rises and sets. The dust in the Martian atmosphere make the Martian sunsets have a rather blue color. Mars's atmosphere, of course, is too thin to protect Mars from meteors well, which is why the bottom half of Mars has so many craters. Some craters hit Mars with so much force a few pieces of Mars went flying into space - even into Earth! People have actually found rocks on Earth that have chemicals in them - chemicals that are like the ones in Martian rocks. These rocks also look like they fell really quickly through the atmosphere, so it is reasonable to think they came from Mars.
Some famous stories were written about this idea. The writers used the name "Martians" for intelligent beings from Mars. In 1898 H. G. Wells wrote The War of the Worlds, a famous novel about Martians attacking the Earth. In 1938, Orson Welles broadcast a radio version of this story in the United States, and many people thought it was really happening and were very afraid. Beginning in 1912, Edgar Rice Burroughs wrote several novels about adventures on Mars.
As of March 2008, scientists have not found life on Mars, either living now or extinct. Several space probes without people have gone to Mars to study it. Some have orbited (gone around) the planet, and some have landed on it. There are pictures of the surface of Mars that were sent back to Earth by some of these probes. Some people are interested in sending astronauts to visit Mars. This would be difficult. The astronauts would be in space for many years, and it could be very dangerous because of radiation from the sun.
Topics of Interest
Mars is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance, due to iron oxide prevalent on its surface.
The geology of Mars, also known as areology (from Greek Arēs and logia), refers to the study of the composition, structure, physical properties, history, and the processes that shape the planet Mars.
Martian soil is the fine regolith found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil.
Water on Mars is an expression for all the water present on the planet Mars. In comparison to Earth, water is much less abundant on Mars in all three states of matter. Most of the water is locked in the cryosphere (permafrost and polar caps), so there are no bodies of liquid water, which could create a hydrosphere. Only a small amount of water vapour is in the atmosphere.
Geysers on Mars are unlike any Terrestrial geological phenomena, where "dark dune spots" and "spiders" are its two most visible features. Their reflectance (albedo), shapes and unusual spider appearance caused a lot of speculation about their origin, ranging from differences in frosting reflectance and explanations involving biological species. However, all current geophysical models correspond to what is thought to be a geyser-like system on Mars. Their shape, and the forces that cause them, are still a matter of debate.
The geography of Mars, also known as areography, entails the delineation and characterization of regions on Mars. Martian geography is mainly focused on what is called physical geography on Earth; that is the distribution of physical features across Mars and their cartographic representations.
Mars, the 4th planet from the Sun, has a very different atmosphere from that of the Earth. There has been much interest in studying its composition since the recent detection of a small amount of methane, which may signal life on Mars; it could also be a geochemical process or the result of volcanic or hydrothermal activity.
The climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth.
Mars has two tiny moons, Phobos and Deimos, which are thought to be captured asteroids.
Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Although fictional Martians have been a recurring feature of popular entertainment, it remains an open question whether life currently exists on Mars, or has existed there in the past.
Fictional representations of Mars have been popular for over a century. Interest in Mars has been stimulated by the planet's dramatic red color, by early scientific speculations that its surface conditions might be capable of supporting life, and by the possibility that Mars could be colonized by humans in the future. Almost as popular as stories about Mars are stories about Martians engaging in activity (frequently invasions) away from their home planet.
NASA's Mars Exploration Rover Mission (MER), is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars. It began in 2003 with the sending of the two rovers — MER-A Spirit and MER-B Opportunity — to explore the Martian surface and geology.
Primary among the mission's scientific objectives is to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. The mission is part of NASA's Mars Exploration Program which includes three previous successful landers: the two Viking program landers in 1976 and Mars Pathfinder probe in 1997.
The exploration of Mars has been an important part of the space exploration programs of the Soviet Union, the United States, Europe, and Japan. Dozens of robotic spacecraft, including orbiters, landers, and rovers, have been launched toward Mars since the 1960s. These missions were aimed at gathering data about current conditions and answering questions about the history of Mars as well as a preparation for a possible manned mission to Mars. The questions raised by the scientific community are expected to not only give a better appreciation of the red planet but also yield further insight into the past, and possible future, of Earth.
The colonization of Mars by humans is the focus of speculation and serious study, as the surface conditions and availability of water on Mars make it arguably the most hospitable planet in the solar system other than Earth. While the Moon has been proposed as the first location for human colonization, unlike Earth's moon, Mars has an atmosphere, giving it the potential capacity to host human and other organic life.
The Mars Pathfinder (MESUR Pathfinder) later called The Carl Sagan Memorial Station was launched on December 4, 1996 by NASA aboard a Delta II just a month after the Mars Global Surveyor was launched. After a 7-month voyage it landed on Ares Vallis, in a region called Chryse Planitia on Mars, in the Oxia Palus quadrangle, on 4 July 1997. During its voyage the spacecraft had to accomplish four flight adjustments on 10 January, 3 February, 6 May and 25 June. The lander opened, exposing the rover called Sojourner that would go on to execute many experiments on the Martian surface.
The Mars Climate Orbiter (formerly the Mars Surveyor '98 Orbiter) was one of two NASA spacecraft in the Mars Surveyor '98 program, the other being the Mars Polar Lander (formerly the Mars Surveyor '98 Lander). The two missions were to study the Martian weather, climate, water and carbon dioxide budget, in order to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.
Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)
|
