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Re: June 21

For you astronomy buffs, June 21 is:
* the summer solstice
* a solar eclipse (in Africa)
* opposition of Mars, the closest it's been to earth in over 10 years

So the sun, moon, earth and Mars will be in almost a perfect straight line.

Tim Folkerts

Hi Tim,

The Earth-Moon-Sun alignment will indeed be quite impressive on the
21st. The alignment with Mars, however, will be rather less perfect.
Mars is actually at opposition on June 13, when it will be 177° from
the Sun in our sky. (It's not a perfect 180° because the orbit of
Mars is inclined to the Earth's orbit.) On June 21, when Mars is
closest to Earth (a mere 0.45 AU, or 67 million km), the
Sun-Earth-Mars angle will be 169°.

By the way, another amusing coincidence is that Mars is at its own
autumnal equinox on June 17. It's a busy month!

My reference for all of this entertainment is Guy Ottewell's
magnificent "Astronomical Calendar 2001." These annual compendia of
astronomical information are a tremendous bargain. For more
information, see http://www.universalworkshop.com/page6.html.

Cheers,
Roger
--
+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Roger A. Freedman
Department of Physics and College of Creative Studies
University of California, Santa Barbara

Mailing address:
Department of Physics
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Santa Barbara CA 93106-9530

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