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Extra-close oppositions of Mars happen every 15 to 17 years, when we pass between Mars and the Sun around the time of its perihelion (closest point to the Sun in orbit). The minimum distance between Earth and Mars has been declining over the years, and in 2003 the minimum distance was 55.76 million km, nearer than any such encounter in almost ...
The following outline is provided as an overview of and topical guide to Mars: Mars – fourth planet from the Sun and the second-smallest planet in the Solar System , after Mercury . Named after the Roman god of war , it is often referred to as the " Red Planet " [ 1 ] [ 2 ] because the iron oxide prevalent on its surface gives it a reddish ...
Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830.
Rotation and Interior Structure Experiment (RISE) is a radio science experiment onboard InSight Mars lander that will use the spacecraft communication system to provide precise measurements of Mars' rotation and wobble. RISE precisely tracks the location of the lander to measure how much Mars's axis wobbles as it orbits the Sun.
An areostationary orbit, areosynchronous equatorial orbit (AEO), or Mars geostationary orbit is a circular areosynchronous orbit (ASO) approximately 17,032 km (10,583 mi) in altitude above the Mars equator and following the direction of Mars's rotation. An object in such an orbit has an orbital period equal to Mars's rotational period, and so ...
Mars has an axial tilt of 25.19°, quite close to the value of 23.44° for Earth, and thus Mars has seasons of spring, summer, autumn, winter as Earth does. As on Earth, the southern and northern hemispheres have summer and winter at opposing times. However, the orbit of Mars has significantly greater eccentricity than that of Earth. Therefore ...
Areosynchronous orbit (ASO): A synchronous orbit around the planet Mars with an orbital period equal in length to Mars' sidereal day, 24.6229 hours. Areostationary orbit (AEO): A circular areosynchronous orbit on the equatorial plane and about 17,000 km (10,557 miles ) above the surface of Mars.
In 1781, he estimated the rotation period of Mars as 24 h 39 m 21.67 s and measured the axial tilt of the planet's poles to the orbital plane as 28.5°. He noted that Mars had a "considerable but moderate atmosphere, so that its inhabitants probably enjoy a situation in many respects similar to ours".