Yes, it’ll be possible to see every planet of the solar system on these December 2011 nights. Given clear skies, they’ll be within reach for the rest of this year.
With the International Astronomical Union reclassifying Pluto as a “dwarf planet” in 2006, that leaves a total of eight known full-fledged planets inhabiting our solar system. In their outward order from the sun, these planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Image credit: Wikimedia Commons
Four of these planets are found in the evening sky, starting at nightfall. Two of them – Venus and Jupiter – shine so brilliantly that they’ll be hard to miss. After all, Venus and Jupiter rank as the third and fourth most brilliant celestial bodies, after the sun and moon. At dusk and nightfall, Venus is found rather low in the southwest sky, while Jupiter shines much higher up in the southern sky.
To see Uranus and Neptune, you’ll undoubtedly need good binoculars or a telescope, and a detailed sky chart. Because the planets revolve around the sun on nearly the same plane that the Earth revolves around the sun, the planets are always found on or near the ecliptic – Earth’s orbital plane projected onto the dome of sky. Even without an optical aid, you can imagine seeing Uranus and Neptune with the mind’s eye, lining up on the ecliptic in between Venus and Jupiter.
As the Earth spins eastward under the heavens tonight, Venus sets first at early evening, followed by Neptune at mid-evening, Uranus around midnight and finally by Jupiter well after midnight. As Jupiter sets in the west, look for Saturn and the moon to rise in tandem in the east.
Mars could be called an evening planet because it now rises in the east before midnight. Mars rises late this evening, followed by Saturn around 2:00 to 3:00 in the morning. Then at long last, Mercury clears the southeast horizon (if it’s level) some one and one-half hours before sunrise. Mars, Saturn and Mercury are relatively easy to see because they shine as brilliantly as first-magnitude stars.
You don’t have to stay up all night to view all the planets. The four evening planets – Venus, Neptune, Uranus and Jupiter – can be viewed at nightfall, and the three morning planets – Mars, Saturn and Mercury – are all visible some 90 to 60 minutes before sunup. As darkness starts to give way to dawn, look for Mars in the southern sky, the moon and Saturn in the southeast and Mercury near the sunrise point on the horizon.
Take advantage of these December 2011 nights to see every planet of our solar system!