Mercury,
July/August 2003 Table of Contents

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Courtesy
of Lowell Observatory. |
by
William Sheehan
Astronomers
obsessed with Mars would do just about anything to observe the Red
Planet during the great oppositions of yesteryear.
Late this summer,
the faster-moving Earth will catch up with and overtake Mars as
the two planets pursue their perennial paths around the Sun. On
August 27, 2003, Mars will come within 55,760,000 kilometers —
slightly closer than it has been in about 60,000 years according
to calculations by Jeff Beish of the Mars Section of the Association
of Lunar and Planetary Observers and Jim DeYoung of the U.S. Naval
Observatory. The last time Mars came this close to Earth, Neanderthals
were producing flaked hand tools in Europe.
Close
oppositions occur once every 15 or 17 years, whenever Earth and
Mars line up when Mars is near its most sunward point, or perihelion.
A collusion of factors, including slight changes over time in Mars’s
orbital eccentricity, will make the coming opposition the most favorable
in recorded human history (see "Why Mars Will Be So Close to
Earth," page 28).
Perihelic
oppositions have been landmark years of Martian studies. At the
perihelic opposition of 1830, German astronomers Johann Mädler
and Wilhelm Beer produced the first map of the planet. In 1862,
astronomers William Rutter Dawes and Norman Lockyer made remarkably
accurate sketches of the planet, and Heinrich d'Arrest of the Copenhagen
Observatory mounted an unsuccessful search for Martian satellites.
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