oppositions of Mars
The Earth-Mars distance fluctuates between about
56 million and 400 million km (35 million and 250 million miles), as the
two planets swing around their respective orbits. The best times for telescopic
viewing are when Mars is in opposition
– that is, close to the Earth and in the opposite part of the sky
from the Sun. These happen every 780 days. But the most favorable oppositions
of all, when the two planets approach as close as possible, occur only at
intervals of between 15 and 17 years, and always in July, August or September.
On Aug. 27, 2003, the opposition distance of Mars from Earth was the closest
it has been for about 60,000 years. Calculations suggest that the last time
they were this close together was when Neanderthals roamed the planet, on
Sep. 12, 57,617 BC. Other significant encounters happened
during the month of August in 1924, 1845 and 1766 but there won't be another
close approach for 284 years. Earth has a more-or-less circular orbit while
Mars takes a more elliptical path around the star. The two planets travel
at different speeds around the Sun, the Earth eventually catching and overtaking
Mars. This means Mars passes closer to Earth than usual at various times
in history, with the 2003 opposition being particularly memorable.
Related category
• MARS
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