Auroras
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PHONE.
CHRISTMAS
MORNING: Mom,
dad, wake up, it's Christmas! If this happens to
you at 5:30 a.m. on Dec. 25th, steal a glance out the
window on your way to the tree. The crescent moon will
be gliding by the bright star Spica--a
pretty close encounter. In some
places the moon will actually blot out the star. It's
a nice way to start the day: sky
map.
AN
EXPLOSION ON THE MOON: So
you thought nothing ever happens on the moon? Think again.
NASA scientists have observed a surprising and powerful
explosion in the lunar Sea of Rains: full
story.
EXPANDING
SUNSPOT: It's
happening again: For the second time in less than a week,
a sunspot is materializing before our very eyes. Just
yesterday sunspot 838 was a barely-visible speck. Now
it is wider than the planet Neptune:

Sunspot
838: Dec. 21-22, 2005. Credit: SOHO
Sometimes,
the magnetic fields of fast-growing sunspots become unstable
and explode. The magnetic field of sunspot 838, however,
does not appear to harbor energy for strong flares. Stay
tuned for updates.
SHRINKING
PLANET: If
you get a telescope for Christmas, point it at Mars--fast!
The red planet is receding from Earth at a speed of 30,000
mph and shrinking as it goes. Using an 8-inch telescope,
Joel Warren
of Amarillo, Texas, took these two pictures of Mars five
weeks apart:
What
a difference: By mid-January, Mars will be only half as
bright as it is tonight, and its apparent diameter will
have decreased from 13 to 9 arcseconds. So now is the
time to observe Mars. Look for it straight overhead after
sunset: sky
map.