How many moons does mars have?
Mars have two satellites, Phobos and Deimos. These moons are irregularly shaped and much smaller than the Earth’s Moon. They were possibly not captured in the same way the Earth’s Moon was. They are thought to be asteroids or rubbles from a collision, which were eventually captured by Mar’s gravitational draw.Since they are too small to cover the sun, a total eclipse never happens in Mars. Odd enough, lunar eclipses occur almost every night.
Phobos, the larger one between the two moons, is egg-shaped and has the dimensions 27x21x19 km. It was named after one of the sons of Ares and Aphrodite. The word ‘phobos’ means fear in Greek and is the root word for ‘phobia’. The satellite phobos is 3000 miles away from Mars and orbits in7.3 hours which means it makes more than 3 orbits in a Martian day. It rises in the west and sets in the east. Phobos is completely invisible from Mars poles. Both Phobos and Deimos have a great deal of craters. It is one reason why they are speculated to be asteroids before they became satellites. Phobos also has parallel grooves, which are 150m long, 25m deep and start from the largest crater and ends on the other side of it. In a few million years, Phobos is believed to cease in existence after a few million years.
Every century, it moves 2 meters closer to Mars surface and eventually may crash into Mars or forma ring of dust around the planet. Deimos is the smaller and outer moon of Mars with the dimensions of 15 × 12.2× 10.4 km and distance of around 23,460 km from Mars. From the surface of Mars, Deimos appears more like a bright spot or star. Although heavily cratered like Phobos, Deimos has tremendous amount of dust covering its surface, which fills and covers up its irregularities. Phobos, on the other hand, is clearer of dust since its distance to Mars could have caused fragments to be pulled off from its surface by Mars’ gravity. Unlike Phobos, it rises from the east and sets in the west. It finishes its orbit in about 30 hours but takes 2.7 martian days since it falls behind Mars’ rotation.
The meaning of the word ‘deimos’ is similar to that of ‘phobos’. It means terror or panic. Deimos, in Greek mythology is the twin brother of Phobos. Both Phobos and Deimos are tidally locked, which means one side of each faces Mars all the time as they orbit around the planet. They were discovered in 1877 by Asaph Hall, an American astronomer. Before the discovery, Johannes Kepler,the German astronomer who is best known for designing the laws of planetary motion, predicted that Mars has two moons. He was correct although his basis was incorrect. He reasoned that since Jupiter has four moons and Earth has two, it follows that Mars have two. Asaph hall, who deliberately searched for the moons found Deimos on August 12, 1877. 6 days after, he sighted Phobos on August 18. He was the one to give the satellites their names.
September 29th, 2009 at 8:38 pm
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