December 2011 Sky from the Keeble Observatory
My apologies for no column last month. If time truly flies when one is having fun,
I must be having the best time of my life! The end of a very busy semester is near,
so I should be better able to stick to deadlines.
In our last column we wrote about some “Chicken Little” events. Unfortunately, there
may be another coming our way. Phobos-Grunt (“Phobos-Ground” in English) is a Russian
probe intended to rendezvous with the Martian moon Phobos, including a lander which
would subsequently return several kilograms of that moon to Earth.
It was launched from the Baikonur Kosmodrome in Kazakhstan on November 8th
– and then things went wrong. The upper stage of the rocket, which was supposed
to fire twice to move it from its initial parking orbit into its trajectory towards
the Red Planet did not fire. It’s not clear what happened, but the spacecraft is
currently stuck in a 200 km high orbit which is expected to decay and re-enter our
atmosphere early next year. Attempts to communicate with the craft have had only
limited success, and the Russian space agency has reportedly declared the mission
a failure. The last opportunity to get it to Mars passed on the 21st
of November. Present concerns are about the fate of some 7.5 metric tons of highly
toxic hydrazine and nitrogen tetroxide fuel still on board. They should vaporize
and burn up on reentry, but nobody has any experience with that much fuel still
on board at reentry. We should note that the Russians have had notoriously bad luck
with their Mars probes – they’ve never had a successful mission.
The US, on the other hand, has high hopes for its next generation rover, dubbed
Curiosity, which was successfully launched on November 26th. In about
8 months it should arrive and we’ll know if the complex landing sequence will work.
(Recall the “airbag” landing systems on previous rovers. This vehicle is about 3,000
pounds, and the airbags would weigh more than that. Instead, it will use a system
of parachutes and retrorockets to slow it for a safe landing.) This will be the
most sophisticated surface probe ever, and it’s mission is to search for evidence
that life may have been possible on a younger, warmer, wetter Mars.
Lunar phases for December: First Quarter was on the 2nd, at 4:52
am; Full Moon on the 10th, at 9:36 am (this will be accompanied by a
total lunar eclipse, but we won’t see it!); Last Quarter on the 17th,
at 7:48 pm; New Moon on the 24th at 1:06 pm.
The Geminid meteor shower returns mid-December, with peak activity expected the
13th through 15th. As usual, your best bet is to get away
from city lights, and look in the hours after midnight as Earth’s rotation carries
us into the stream of meteoroids.
Winter Solstice takes place at 12:30 am on the 22nd, when the Sun is
at its most southerly position in the sky.
Predawn planet watchers can find Saturn to the southeast after rising around 3:00
am, about 30 degrees above the horizon at sunrise early in the month. Mars is high
to the south at 66 degrees elevation. Mercury returns to the eastern twilight around
mid-month, and will be climbing higher as we approach year’s end.
Jupiter begins the month in the evening skies, to the east at sunset, nearly due
south at 8:00 pm and setting a few hours after midnight. Venus is very bright to
the southwest, starting December very low on the horizon, but climbing higher as
the weeks pass.
Our midmonth overhead view, about two hours after sunset, finds the constellation
Andromeda at zenith. The moon is approaching last quarter, but on a clear night
without haze it should be easy to pick out the iconic Andromeda galaxy a few degrees
to the northwest. This would be a good night for binoculars. Start with Andromeda,
and sweep your view toward the eastern horizon. You’ll find the Pleiades. The bright
star a few degrees below is Aldebaran, and the open cluster just above and to the
right of Aldebaran is the Hyades cluster. Closer to the horizon is Orion – but this
constellation hardly needs introduction, and is easily recognized by nearly everybody.
To your left and a little lower than Orion you’ll see the “twins” – Castor and Pollux
To the north, Ursa Major is so low that you may have difficulty finding it … the
“handle” is below the horizon, so the familiar asterism of the Big Dipper will not
be obvious. Vega is to the northwest, below the Northern Cross of Cygnus.
If readers have questions about astronomy or science in general that you would like
covered in one of these columns, please feel free to contact me at email@example.com.