Celestial Lights
By Phyllis Burton Pitluga
November 28, 2008 San Miguel de Allende

Photo credits: (NASA Hubble Space Telescope)

Venus and Jupiter create a celestial choreography

You are probably noticing the two bright “stars” in our evening sky. They are the planets Venus and Jupiter. As November ends they are quite close in the sky yet they are far apart in distance from each other. The order of the easily visible planets out from the Sun is Mercury, Venus, Earth (visible because we are standing on it), Mars, Jupiter and Saturn. Venus and Jupiter are about 4 billion miles apart right now.

As the evenings pass this month, Venus and Jupiter will move apart in the sky. Right now Venus is swinging out away from the setting Sun while Jupiter is setting closer and closer to the Sun. Earth’s faster motion is especially contributing to the disappearance of slow-moving Jupiter behind the Sun. 

Both planets are fascinating to view through a telescope. Venus changes phases going, now, from a nearly full Venus, shrinking to a half Venus by January and to a skinny but tall crescent shape as it gets ready to pass between Earth and the Sun in late March. Jupiter is orbited by numerous moons – four of them large enough to easily track in a small telescope. 

Geminid meteor shower December 13

An astounding 120 meteors an hour (2 per minute) are predicted to rain across our sky on Saturday evening, December 13th and into the wee hours of the 14th. From a dark-sky site, let your eyes adapt to the darkness to see ever-fainter stars and meteors. Look to the east about 7:30pm, overhead by midnight and in the west by dawn. Meteor showers are more impressive after midnight because the Earth is orbiting into the shower particles. Meteors streak across a wide expanse of the sky so you do not need binoculars or telescopes – just observe with your eyes.

The Geminid meteor shower particles are the only grains we know of that are coming from an asteroid (other meteor-shower grains come from decayed comets). Asteroids are rocky worlds that orbit between Mars and Jupiter. They range in size up to 600 miles (900 kilometers). The Asteroid Belt is a region where there wasn’t enough matter to pull together to become a planet when the Solar System formed 4.5 billion years ago. 

The asteroid 3200 Phaethon must be colliding with other little rocky worlds in its vicinity to be providing the debris field that we currently orbit through every December. These grains heat up from friction with Earth’s upper atmosphere, creating the glowing trails across our sky. The grains burn up and do not reach the surface of the Earth. Enjoy the celestial lights of our holiday season—the Geminid Meteor Shower.

Sky Calendar, December 2008  By following the Moon as the biggest and brightest “pointer” in the sky, during the month you can identify different planets and bright stars. On following nights you can relocate them but without the Moon – the Moon moves about 25 times its own diameter from one night to the next.

The Moon is much closer than the planets of our Solar System and the stars are even farther. So, when the Moon appears close to a celestial light they are truly separated by millions, billions or trillions of miles.

In early December, Jupiter rapidly sinks in the southwestern evening twilight to become lost in the glare of the Sun by the end of the month. Venus is brilliant in the southwestern sky until mid-March. Saturn rises at midnight and is overhead by dawn. 


Nov. 30-Dec. 1, Sunday & Monday: Venus is 4 moon diameters south of Jupiter with the Crescent Moon nearby.


Dec. 5, Friday: First Quarter Moon (looks like half a moon but half is turned away from us; of the half we see, half is lit = one quarter)

Dec. 11, Thursday: The nearly Full Moon is one diameter above the Pleiades star cluster. Locate it by the Moon and look at the star cluster with binoculars on nights when the bright Moon isn’t nearby.

Dec. 11, Thursday: Full Moon is closest for the year causing large tides.

Dec. 13, Saturday: Geminid meteor shower (see article above).

Dec. 15, Monday: The Waning Gibbous Moon passes one and a half diameters beneath the Beehive star Cluster. Like the Pleiades on the 11th, only use our Moon to locate the cluster in the sky.

Dec. 18, Thursday: The Waning Gibbous Moon passes twelve of its diameters below Saturn.

Dec. 19, Friday: Last Quarter Moon.

Dec. 22, Saturday: Winter Solstice in the Northern Hemisphere when the midday Sun is lowest and the nights are longest. Here in the tropics it isn’t nearly as noticeable as farther north.

Dec. 27, Saturday: New Moon (= no Moon because the dark side faces Earth).

Dec. 28, Sunday: Mercury, Jupiter and the Crescent Moon are together low in the southwest evening sky. 

Phyllis Burton Pitluga is Astronomer Emerita, Adler Planetarium & Astronomy Museum, Chicago.