Astronomy on Mars Reference Libraries

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Positional Astronomy
2004-10-19 04:45:43

Positional Astronomy -- Positional astronomy is the study of the positions of celestial objects. This is the oldest branch of astronomy and dates back to antiquity. Observations of celestial objects are important for religious and astrological purposes, as well as for timekeeping. Ancient structures associated with positional astronomy include: -- Chichn Itz -- The Medicine Wheel...

Perseids Meteor Shower
2004-10-19 04:45:41

Perseids Meteor Shower -- Like most meteor showers, the Perseids are caused by comet debris. As comets enter the inner solar system, they are warmed by the sun and peppered by the solar wind, which produces the familar tails that stretch across the night sky when a bright comet is close to Earth. Comet tails are made of tiny pieces of ice, dust, and rock which are spewed into...

2004-10-19 04:45:41

The Moon -- The Moon is the largest satellite of the Earth, and is occasionally called Luna (Latin for moon) to distinguish it from the general use of the word "moon". The Moon is distinguished from the satellites of other planets by its initial capital letter; the other moons are described in the natural satellite article. The words moon and month come from the same Old English root word....

2004-10-19 04:45:40

The Planet Mars -- in astronomy, 4th planet from the sun, with an orbit next in order beyond that of the earth. Physical Characteristics Mars has a striking red appearance, and in its most favorable position for viewing, when it is opposite the sun, it is twice as bright as Sirius, the brightest star. Mars has a diameter of 4,200 mi (6,800 km), just over half the diameter of the...

Mars Moon -- Phobos
2004-10-19 04:45:40

Mars' Moon Phobos -- in astronomy, innermost moon, or natural satellite, of Mars. Phobos orbits Mars at a distance of only 9,378 km (5,627 mi), closer to its planet than any other moon in the solar system. In fact, it is so close that the force of Mars's gravity is stronger than the force keeping the moon in its orbit, so the radius of Phobos's orbit is decreasing at the rate of about 1.8 m...

Word of the Day
  • Small missiles, especially grape, canister, fragments of iron, and the like, when fired, as upon an enemy at close quarters.
  • To fire mitraille at.
The word 'mitraille' comes from the Old French 'mitaille', meaning 'small coins', sometimes used to mean 'scrap iron'.