Nissan
22-12-2008, 04:54 PM
Mars
God of War
With the Terran system well behind us, we next encounter a beautiful, bright red world. This is the planet Mars, and it is the fourth planet from the Sun. It was named after the Roman god of war because its color reminded observers of a bloody Roman battlefield. Early astronomers believed they could see faint, dark lines crossing the surface of the planet. Some believed these to be artificially built canals. This gave rise to some of the early speculation of intelligent life on Mars. These lines were later found to be an optical illusion. Later unmanned missions to the planet found no evidence of the so-called canals. Still, there is perhaps no other body in the Solar System that has intrigued us more than Mars. To this very day, it is still one of the most likely candidates for extraterrestrial life. In fact, meteorites recently discovered in Antarctica are believed to have originated from the red planet. These ancient Martian rocks may contain fossils of tiny bacteria. If this turns out to be true, it will be the first evidence that life evolved on other planets besides Earth.
The Red Planet The bright red color of Mars has earned it the name of red planet. This unique color is caused by the chemistry of its surface. Mars does have a thin atmosphere, which helps cause iron compounds to oxidize. It is this iron oxide in the rocks and sand that gives the planet it reddish-brown color. It could very appropriately be called the "rusty" planet. We have learned a great deal about Mars in the last few decades. Several unmanned space missions have been sent to explore the red planet. Several Mariner spacecraft orbited the planet in the mid and late 1960's. In 1975, two Viking spacecraft landed on the surface, sending back the first color pictures of this alien world. Recently, the Mars Pathfinder mission visited the planet. A small roving vehicle known as the Sojourner Rover explored the surface sending back the sharpest pictures to date. Scientists continue to be fascinated with Mars because of its similarities to Earth. Some have even suggested that we may be able to colonize the planet in the not too distant future. If the planet does turn out to be completely lifeless, it may be a candidate for a process known as terraforming. This process would involve using various chemical and biological means to make the planet warmer and the atmosphere more hospitable for human life.
Features of Mars
Mars is a small, rocky world about half the size of Earth. As small as it is, however, it is a planet of extremes. Mars is the home of the largest known volcano in the Solar System. Olympus Mons is an extinct volcanic crater that rises 15 miles above the Martian surface. That is over twice the height of the tallest mountain on Earth, Mt. Everest. It is a scar so large it can be seen from Earth. Another gigantic feature of the red planet is Valles Marinares. This is the Martian equivalent of the Grand Canyon. This one is much bigger, however. Valles Marinares stretches 3000 miles (4829 km) along the surface of Mars and is 435 miles (700 km) wide at its widest point. If this canyon existed on Earth, it would stretch across the continental United States from coast to coast! During the Martian winters, the poles of the planet are covered with large sheets of water ice. Several features that resemble riverbeds suggest that there may have been running water on Mars at one time. The thin atmosphere of Mars is composed mainly of carbon dioxide. Winds of up to 300 miles per hour whip up enormous dust storms that constantly erode and reshape the surface of the planet. With an average surface temperature of 60 degrees below zero, it may not seem very hospitable. But with its thin atmosphere and abundance of water, Mars remains the most likely candidate for life anywhere in the Solar System. A future manned mission to the planet is in the works. Only then will we be able to tell if the red planet is really a dead planet.
Statistics for Mars
Diameter ...... 4220 miles (6794 km) Number of Natural Satellites ...... 2 Mean Distance from the Sun ...... 141,050,000 miles (227,940,000 km) Rotational Period ...... 24.62 hours Orbital Period ...... 687 days Orbital Eccentricity ...... 0.093 Orbital Inclination ...... 1.85 degrees Inclination of Axis ...... 23.98 degrees Mean Surface Temperature ...... -81° F (-63° C) Main Atmospheric Component ...... Carbon Dioxide Atmospheric Pressure ...... 0.007 bars Atmospheric Depth ...... 100 miles (161 km) Apparent Magnitude ...... -2.01
file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot.jpgfile:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot-1.jpg
Chariot of Fear
Phobos [FOH-bohs] is the innermost of Mars' moons and is the largest. It is closer to its planet than any other moon in the Solar System. It is also one of the smallest moons in the Solar System. Phobos was named after Fear, one of the charioteers of the Roman god, Mars. In Greek mythology, Phobos is one of the sons of Ares (Mars) and Aphrodite (Venus). Phobos and its cousin, Deimos, were discovered in 1877 by American astronomer Asaph Hall while observing Mars at the U.S. Naval Observatory in Washington.
A Tiny Moon
Phobos is a tiny moon. At only 17 miles in length, it is the larger of Mars' two moons. At a distance of 5826 miles (9380 km) from Mars, Phobos appears as no more than a tiny, bright dot in the Martian sky. It is so close to Mars that it cannot be seen above the horizon from all points on the planet. This moon has a highly irregular shape, looking more like an asteroid than a moon. In fact, some astronomers believe that it may have been a large asteroid that was captured by the gravitational pull of Mars. Others have found evidence that contradicts this theory. We may never know exactly where this moon came from, or why it has such a strange shape. An interesting feature of Phobos is the fact that it appears to revolve around Mars in the opposite direction as its cousin Deimos. Both moons revolve in the same direction, but Phobos revolves in less than eight hours, only 1/3 the time it takes Mars to rotate on its axis. Phobos orbits Mars more than twice during each Martian day! This is because it orbits below the synchronous orbit radius of Mars. Because its orbit is so low, tidal forces are causing its orbit to get lower every year. In about 50 million years, Phobos will either crash into the surface of Mars or be broken up into a ring.
Features of Phobos
Phobos is a rather unremarkable object. It is essentially just a large rock potted with several craters. The largest is named Stickney, after discoverer Asaph Hall's wife. This huge gash is six miles wide, nearly 1/3 the size of the moon itself! Two other large craters are named Hall and Roche. These are about half the size of Stickney. Several other smaller craters dot the moon's surface with an average size of 500 feet (152 m). Another interesting feature found on Phobos is the presence of surface fractures. These were probably caused by the giant impacts that formed the large craters, or from the strong gravitational effects of Mars. Phobos is believed to be composed of carbon-rich rock like that found in C-type asteroids that exist in the outer asteroid belt. Due to the moon's low density, however, it is unlikely to be pure rock. It is probably composed of part rock and part ice. The Soviet spacecraft, Phobos 2, detected some type of gas being ejected from Phobos. Astronomers are not sure what is causing this, but the best theory suggests water may be escaping from the moon's interior. Phobos has no atmosphere and no magnetic field.
Statistics for Phobos
Discovered by ...... Asaph Hall Year of Discovery ...... 1877 Diameter ...... 12.4 x 14.3 x 17.4 miles (27 x 21.6 x 18.8 km) Mean Distance from Mars ...... 5826 miles (9380 km) Rotational Period ...... 7.66 hours Orbital Period ...... 7.66 hours Orbital Eccentricity ...... 0.01 Orbital Inclination ...... 1.1 degrees Main Atmospheric Component ...... none Apparent Magnitude ...... 11.3
God of War
With the Terran system well behind us, we next encounter a beautiful, bright red world. This is the planet Mars, and it is the fourth planet from the Sun. It was named after the Roman god of war because its color reminded observers of a bloody Roman battlefield. Early astronomers believed they could see faint, dark lines crossing the surface of the planet. Some believed these to be artificially built canals. This gave rise to some of the early speculation of intelligent life on Mars. These lines were later found to be an optical illusion. Later unmanned missions to the planet found no evidence of the so-called canals. Still, there is perhaps no other body in the Solar System that has intrigued us more than Mars. To this very day, it is still one of the most likely candidates for extraterrestrial life. In fact, meteorites recently discovered in Antarctica are believed to have originated from the red planet. These ancient Martian rocks may contain fossils of tiny bacteria. If this turns out to be true, it will be the first evidence that life evolved on other planets besides Earth.
The Red Planet The bright red color of Mars has earned it the name of red planet. This unique color is caused by the chemistry of its surface. Mars does have a thin atmosphere, which helps cause iron compounds to oxidize. It is this iron oxide in the rocks and sand that gives the planet it reddish-brown color. It could very appropriately be called the "rusty" planet. We have learned a great deal about Mars in the last few decades. Several unmanned space missions have been sent to explore the red planet. Several Mariner spacecraft orbited the planet in the mid and late 1960's. In 1975, two Viking spacecraft landed on the surface, sending back the first color pictures of this alien world. Recently, the Mars Pathfinder mission visited the planet. A small roving vehicle known as the Sojourner Rover explored the surface sending back the sharpest pictures to date. Scientists continue to be fascinated with Mars because of its similarities to Earth. Some have even suggested that we may be able to colonize the planet in the not too distant future. If the planet does turn out to be completely lifeless, it may be a candidate for a process known as terraforming. This process would involve using various chemical and biological means to make the planet warmer and the atmosphere more hospitable for human life.
Features of Mars
Mars is a small, rocky world about half the size of Earth. As small as it is, however, it is a planet of extremes. Mars is the home of the largest known volcano in the Solar System. Olympus Mons is an extinct volcanic crater that rises 15 miles above the Martian surface. That is over twice the height of the tallest mountain on Earth, Mt. Everest. It is a scar so large it can be seen from Earth. Another gigantic feature of the red planet is Valles Marinares. This is the Martian equivalent of the Grand Canyon. This one is much bigger, however. Valles Marinares stretches 3000 miles (4829 km) along the surface of Mars and is 435 miles (700 km) wide at its widest point. If this canyon existed on Earth, it would stretch across the continental United States from coast to coast! During the Martian winters, the poles of the planet are covered with large sheets of water ice. Several features that resemble riverbeds suggest that there may have been running water on Mars at one time. The thin atmosphere of Mars is composed mainly of carbon dioxide. Winds of up to 300 miles per hour whip up enormous dust storms that constantly erode and reshape the surface of the planet. With an average surface temperature of 60 degrees below zero, it may not seem very hospitable. But with its thin atmosphere and abundance of water, Mars remains the most likely candidate for life anywhere in the Solar System. A future manned mission to the planet is in the works. Only then will we be able to tell if the red planet is really a dead planet.
Statistics for Mars
Diameter ...... 4220 miles (6794 km) Number of Natural Satellites ...... 2 Mean Distance from the Sun ...... 141,050,000 miles (227,940,000 km) Rotational Period ...... 24.62 hours Orbital Period ...... 687 days Orbital Eccentricity ...... 0.093 Orbital Inclination ...... 1.85 degrees Inclination of Axis ...... 23.98 degrees Mean Surface Temperature ...... -81° F (-63° C) Main Atmospheric Component ...... Carbon Dioxide Atmospheric Pressure ...... 0.007 bars Atmospheric Depth ...... 100 miles (161 km) Apparent Magnitude ...... -2.01
file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot.jpgfile:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot-1.jpg
Chariot of Fear
Phobos [FOH-bohs] is the innermost of Mars' moons and is the largest. It is closer to its planet than any other moon in the Solar System. It is also one of the smallest moons in the Solar System. Phobos was named after Fear, one of the charioteers of the Roman god, Mars. In Greek mythology, Phobos is one of the sons of Ares (Mars) and Aphrodite (Venus). Phobos and its cousin, Deimos, were discovered in 1877 by American astronomer Asaph Hall while observing Mars at the U.S. Naval Observatory in Washington.
A Tiny Moon
Phobos is a tiny moon. At only 17 miles in length, it is the larger of Mars' two moons. At a distance of 5826 miles (9380 km) from Mars, Phobos appears as no more than a tiny, bright dot in the Martian sky. It is so close to Mars that it cannot be seen above the horizon from all points on the planet. This moon has a highly irregular shape, looking more like an asteroid than a moon. In fact, some astronomers believe that it may have been a large asteroid that was captured by the gravitational pull of Mars. Others have found evidence that contradicts this theory. We may never know exactly where this moon came from, or why it has such a strange shape. An interesting feature of Phobos is the fact that it appears to revolve around Mars in the opposite direction as its cousin Deimos. Both moons revolve in the same direction, but Phobos revolves in less than eight hours, only 1/3 the time it takes Mars to rotate on its axis. Phobos orbits Mars more than twice during each Martian day! This is because it orbits below the synchronous orbit radius of Mars. Because its orbit is so low, tidal forces are causing its orbit to get lower every year. In about 50 million years, Phobos will either crash into the surface of Mars or be broken up into a ring.
Features of Phobos
Phobos is a rather unremarkable object. It is essentially just a large rock potted with several craters. The largest is named Stickney, after discoverer Asaph Hall's wife. This huge gash is six miles wide, nearly 1/3 the size of the moon itself! Two other large craters are named Hall and Roche. These are about half the size of Stickney. Several other smaller craters dot the moon's surface with an average size of 500 feet (152 m). Another interesting feature found on Phobos is the presence of surface fractures. These were probably caused by the giant impacts that formed the large craters, or from the strong gravitational effects of Mars. Phobos is believed to be composed of carbon-rich rock like that found in C-type asteroids that exist in the outer asteroid belt. Due to the moon's low density, however, it is unlikely to be pure rock. It is probably composed of part rock and part ice. The Soviet spacecraft, Phobos 2, detected some type of gas being ejected from Phobos. Astronomers are not sure what is causing this, but the best theory suggests water may be escaping from the moon's interior. Phobos has no atmosphere and no magnetic field.
Statistics for Phobos
Discovered by ...... Asaph Hall Year of Discovery ...... 1877 Diameter ...... 12.4 x 14.3 x 17.4 miles (27 x 21.6 x 18.8 km) Mean Distance from Mars ...... 5826 miles (9380 km) Rotational Period ...... 7.66 hours Orbital Period ...... 7.66 hours Orbital Eccentricity ...... 0.01 Orbital Inclination ...... 1.1 degrees Main Atmospheric Component ...... none Apparent Magnitude ...... 11.3