![]() ![]() The heated and cooler air becomes unstable, and the heated air then rises taking dust up into the Martian atmosphere with it, like thunderstorms on the Earth. The air closer to the surface is heated and cooler air is present above it. The formation of Martian dust storms (and dust storms on the Earth’s surface as well) are due to the surface of Mars being strongly heated by incoming solar radiation that heats up the surface. The canal-like albedo features are due to a contrast effect between the light and dark zones over the surface.ĭownload a free copy of the classical albedo map of Mars for the observer to use as reference at the telescope. The North and South Polar Caps (NPC and SPC) will change in size according to the current martian season over that hemisphere. The darker albedo features shown are typically visible during the majority of apparitions/oppositions. Not all features noted on the map are visible to an observer at any one apparition/opposition as it depends upon the hemisphere of the planet that is pointing towards the earth (Northern Hemisphere during aphelic oppositions and Southern Hemisphere during perihelic oppositions) as well as the presence of dust and clouds over the surface of the planet over time. in 1877 (August 12 for Deimos and August 18 for Phobos).Ī map of the classical albedo features over the planet Mars that I produced. Both Martian moons were discovered by the American astronomer Asaph Hall, III (1829-1907) at the United States Naval Observatory in Washington, D.C. Since its period is longer than the Martian day (24.7 hours (1 Sol)) an observer on the Martian equator would see it rise and set after ~2.5 days. Deimos (“Terror” in Greek) is the outer moon (mean radius of 3.9 miles (6.2 km)) that orbits Mars at 14,580 miles (23,460 km) in a period of 30.3 hours rising in the east and setting in the west. It orbits Mars in a period of 7 hours 39 minutes and appears to rise in the west and move across the Martian sky in 4 hours 15 minutes or less, and set in the east, twice each Martian day. Mars has two satellites named Phobos (“Fear” in Greek) is the inner potato-shaped moon (mean radius of 7 miles (11 km)) of Mars that orbits the red planet at an average distance of 3,700 miles (6,000 km) from the Martian surface. The atmosphere of Mars is composed primarily of carbon dioxide (96%, CO2), argon (1.93%, Ar), nitrogen (1.89%, N2), oxygen (0.146%, O2), and water vapor (0.021%, H2O). The surface gravity of Mars is 38% the earths. The main surface pressure of Mars is therefore 0.6% that of the earth's (101.3 kilopascals or 14.69 PSI). This ranges from 30 pascals (0.0044 PSI) and the Olympus Mons to 1155 pascals (0.1675 PSI in Hellas Planitia). The mean surface pressure on the planet Mars is 600 pascals (Pa, or 0.087 PSI). The axial tilt of Mars is 25.2 degrees compared to the earths axial tilt of 23.5 degrees. The rotation period of Mars is equal to 24 hours 37 minutes 22.7 seconds (or 1.03 days, also known as a Sol). The diameter of Mars is equal to 4221 miles (6792 kilometers, or 53% the earths diameter). ![]() The synodic period of the planet Mars is equal to 780 days (or 2.1 years) Which is the time required for a celestial body to return to a position in relation to another celestial body, or the time required between successive oppositions of the planet. The orbital period of Mars equals 687 days 1.88 years, or the sidereal period (orbital period of a celestial body required to return to the same point among the stars). Mars orbits the sun at an average distance of 146 million miles 235,000,000 kilometers, 1.52 astronomical units (AU, one astronomical unit equals approximately 93 million miles or 150 million kilometers). The planet Mars is the 4th planet from the sun. If the motion of Mars is traced in the sky it may produce a zig-zag or or looping motion depending upon the position of the planet above or below the ecliptic. This is analogous to two runners racing on a track and the runner on the outside lane (the planet Mars orbiting the Sun beyond the earth) appears to be ahead but as the runner on the inside track (the Earth within its inner orbit around the Sun) has a shorter track he is able to catch up to the outside runner and pass him on the track. Retrograde motion is due to the fact that the outer planets orbit the sun at lesser speeds then the earth in its orbit. This forward and backward motion of Mars and the outer planets in the sky is known as retrograde motion. The planet Mars, as well as the other outer planets to lesser degrees, appears at times to move towards the east in the sky among the constellations (called direct motion) then briefly stop its eastward motion and begins to go backwards towards the West for a short period of time and then finally resume its normal eastward motion in the sky.
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