In case you are wondering, I am referring to the planets Venus and Jupiter on the 11th through the 15th of March, 2012. They are absolutely spectacular in the western sky just after the Sun has set. To see them, go outside after sunset but before the sky is fully dark and look up in the general direction of where the sun has set (west). If skies are clear, you simply cannot miss the two bright planets near each other in the sky.
Venus is the brighter of the two. The pair are so bright that they are easily spotted during twilight so don’t wait until dark. After sunset, Venus and Jupiter appear as brilliant diamonds against a velvet blue twilight sky. They are putting on a dramatic show night after night as their positions can be seen to change. This is one of those perfect times to share the sky with kids.
Over the next three days, Jupiter will appear to descend closer to the horizon as Venus rises higher above the horizon. So, the two planets will pass each other. The closest they get is about 3 degrees on the 12th of March 2012. This is about the same separation in the sky as 6 full moons end to end. That may sound like a lot but when you see it for yourself, you may be amazed how close Venus and Jupiter appear. If weather permits, keep observing the pair over successive nights to see the apparent motion.
Despite the fact that the pair are getting cozy in the sky, Venus and Jupiter are in fact hundreds of millions of miles apart. Jupiter is the fifth planet from the Sun and Venus is the second. Earth is the third planet so Jupiter is on an outside track (relative to us) and Venus is on the inside track as the planets orbit the Sun. Jupiter is much farther away from us, but its huge size makes up for that and it still seems relatively bright.
In scientific terms, the alignment we see is called a planetary conjunction. This happens when two planets have similar right ascension. Alignments like these have happened before and will continue to happen because all the planets tend to stay close to a line in the sky called the ecliptic. This is the line traced out by the motion of the Sun. Eventually, two (and sometimes more) planets will appear in the same part of the sky. As such, these conjunctions have no real significance other than the fact that they are marvelous to see. This will be one of the better planetary conjunctions for some time so go out and see the dazzling pair in west. All you will need are your eyes and clear skies to the west!