Photo of the Week. The Earth's shadow, cast on the
atmosphere after sunset, rises over the sea.
Astronomy news for the two weeks starting Friday, January 1,
2016.
The next skylights will appear January 15, 2016. Best wishes for
the new year.
The last time Skylights kicked off the New Year was in 2010. And
we begin it with the third quarter Moon,
which rises New Year's night almost right on the phase in North
America. It then fades as a waning crescent until it
disappears at new Moon on Saturday, January 9. Your last easy view
of it will be the morning of Friday the 8th. The Moon will
reappear as a slim waxing crescent the
evening of Monday the 11th, which terminates at first quarter on Saturday the 16th. The morning of
Sunday the 3rd finds the Moon just west of Mars; by the following
morning the Moon will be well east of the red planet. Then the
morning of Wednesday the 6th look for the Moon to stand northwest
of Venus and
Saturn. The following morning it will be to the northeast of
the pair.
With Venus rising later each morning and Saturn rising earlier,
the two approach each other. The morning of Saturday the 9th,
Venus will appear under half degree from fainter Saturn, closest
passage taking place with the pair out of sight prior to their
rising shortly before 5 AM, after which they will separate from
their position north of the star Antares. Well to the west of the
two, Mars now rises around 1:30 AM to the east of Spica in Virgo. Rising before 10:30 PM,
Jupiter dominates the late evening and transits the meridian to the south about as Venus
rises.
The Moon passes apogee, where
it is farthest from Earth, on Saturday the 2nd. On the same date,
around 5PM CST the Earth passes perihelion, where it is closest to
the Sun, 91.404 million miles (147.1 million kilometers), less
than two percent closer than average. Since we are closest to the
solar furnace in northern-hemisphere winter, the Sun's distance
obviously has little to do with the seasons, which are produced by
the 23.4 degree tilt of the rotation axis relative to the orbital
perpendicular. Because of the tilt and the Earth's orbital
eccentricity, latest sunrise is not at the solstice passage but on Tuesday the 5th. For the same
reasons, earliest sunset was on December 8; already the evenings
are notably lighter. The Moon then passes perigee, when it is
closest to Earth (about five percent closer than average), on
Thursday the 14th.
At opposite ends of the solar system, Mercury passes inferior
conjunction with the Sun (more or less between us and the Sun)on
Thursday the 14th, while Pluto goes through solar conjunction on Tuesday the 5th,
In between, Jupiter enters
Retrograde, westerly motion against the stars, on Friday the
8th.
If you can bear the cold, the Quadrantids, one of the best meteor showers of the
year, one that can deliver more than 100 meteors per hour, is at
its best the morning of Monday, January 4. The Moon cooperates by
being in the waning crescent phase and not all that bright. Named
after the defunct constellation Quadrans, the Quadrant (not far
off the handle of the Big
Dipper), the shower's origin is uncertain.
With the Sun not far to the east of the winter solstice, the
traditional keeper of the summer
solstice, Gemini, rides
high, Taurus with its Hyades and Pleiades clusters to the west,
dim Cancer (recognizable in a dark
sky by its central "Beehive"
cluster) to the east. This is a near-perfect time for Orion, recognizable by his three-
star Belt, with the brightest
star of the sky, Sirius, shining
to the southeast of him.
