These two planets will be growing steadily closer together till they reach conjunction in the pre-dawn sky on Feb. 1. The last time Venus and Jupiter had such a close morning rendezvous was in Nov. 2004. The next morning conjunction for these two will be in May 2011.
You can Google “planetary conjunction” to get a more precise definition of what a conjunction is, but if you can imagine a celestial grid like latitude and longitude on a map, a conjunction occurs when the planets appear on the same longitude. For stargazing 101, what a conjunction means is that the planets in question appear really close together.
Venus is the second brightest object in our night sky after the moon. Jupiter is the third. Venus will appear larger and brighter than giant Jupiter because of its proximity to Earth and the Sun. Venus is about the size of the Earth, roughly 7,500 miles in diameter. Jupiter is about 90,000 miles in diameter. Venus is approximately 126 million miles from Earth while Jupiter is about 560 million miles away.
The conjunction will be the opening act for many morning stargazers. On Feb. 4 a waning crescent moon will join the show.
All three of the night’s brightest objects will combine to create a glimmering triangle on the southern horizon. Venus and Jupiter will appear about 3 degrees apart and the moon will hang about 5 degrees below them.
For those who don’t realize that 6 o’clock comes twice in the same day, mark your calendars for an encore later in 2008. In the early evening, a couple of hours after sunset, on Dec. 1, a waxing sliver of moon will join our two vagabond planets for a repeat performance. All three players will be located in the constellation Sagittarius, in the southwestern sky. Venus and Jupiter will be a little farther apart than they were for the February conjunction and the moon will form the top of the triangle.
These cyclic conjunctions of Venus and Jupiter will continue in pairs, with the first conjunction appearing in the morning sky, followed by the evening encore about 10 months later – then the morning rendezvous repeated about two-and-a-half years later, etc.
As mentioned above, the next morning conjunction will be in May 2011, followed by an evening conjunction in March 2012.
The February night skies will continue to be an object of astronomers’ attention with a total lunar eclipse occurring on the night of Feb. 20. Then on Feb. 24 Saturn will be in opposition, which means it will be at its closest point to Earth. This will be a good chance to get a look at Saturn’s rings.