Mars, Saturn, Regulus put on evening show in July skies

by William Atkins

Monday, 30 June 2008

Page 2 of 3 On July 6th, the Moon will be further eastward from, and below, the three bodies at about one hour after sunset in the western sky. Regulus, Saturn, and the Moon will form a triangle, with Mars very close to Saturn. Saturn, with a golden (yellowish-white) color, will be the brightest of the three bodies (Mars, Saturn, and Regulus)—at a magnitude of about +0.6. The bluish-white star Regulus will be at a magnitude of 1.4, which the orangey Mars will be the least bright of the three bodies at a magnitude of +1.6. Magnitude of stars and reflected bodies is measured such that each number difference, say between 1 and 2, is a difference of 2.5 times of brightness. Also, the smaller numbers represent brighter objects. Thus, Saturn will appear over twice as bright as Mars. By July 10th, Mars and Saturn will look even closer, as they appear to be separated by less than one degree—actually 0.7 degree. Mars is just below and to the left of Saturn at this time. This conjunction of the two planets is considered by astronomers to be the best planet-to-planet conjunction for 2008. By July 11th, Mars will be noticeably further away from Saturn, and on its left. On July 14th the Moon will be at its farthest point from the Earth, what we call its apogee. During this first two weeks in July, Mars is about 195 million miles (313,800 million kilometers) away (over twice the distance of the Earth from the Sun). Saturn is almost 1,000 million [1 billion] miles (1.4 billion kilometers) from Earth. Regulus is over 400,000,000 million [400 trillion] miles (645 trillion kilometers) away—about 77 light-years. It takes Saturn nearly 30 Earth-years to move around the Sun, while it takes us on Earth only one year to make a circuit around our star. Mars takes about 1.88 Earth-years to revolve once around the Sun. By the end of July, Mars will be about 11 degrees to the left of Saturn. Light coming from these bodies takes a short or long period of time, depending on their distances. Check out page three. << First page <   1 2 3 Next page > Last page - Post your comment >>

 

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