Mercury is the innermost and smallest planet in our solar system,
orbiting the Sun once every 88 days. It ranges in brightness from
about −2.0 to 5.5 in apparent magnitude. The planet remains
comparatively little known: the only spacecraft to approach Mercury
was Mariner 10 from 1974 to 1975, which mapped only 40%–45% of the
planet's surface. Physically, Mercury is similar in appearance to
Moon as it is heavily cratered. It has no natural satellites and no
real atmosphere. The planet has a large iron core which generates a
magnetic field about 1% as strong as that of the Earth. Surface
temperatures on Mercury range from about 90 to 700 K, with the
subsolar point being the hottest and the bottoms of craters near the
poles being the coldest.
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Today's selected anniversaries:
Washington, D.C. was burnt down during the War of 1812.
The New York Sun perpetrated the Great Moon Hoax.
The Kuomintang was founded by Sung Chiao-jen and Dr. Sun Yat-sen in
In the Polish-Soviet War, the Battle of Warsaw ended with a Russian
The Voyager 2 spacecraft reached Neptune, the last planet it could
visit before leaving the solar system.
Wikiquote of the day:
"Being inoffensive, and being offended, are now the twin addictions
the culture." -- Martin Amis