After creeping toward each other steadily for the last few
months, Venus and Jupiter finally came together in what astronomers call
a planetary conjunction Tuesday, putting on a spectacular show for
skywatchers around the world.
The two planets lit up the night sky
in tandem, appearing so close together that observers could blot them
both out with just a few fingers held at arm's length. And they provided
a lasting display, blazing bright above the western horizon for hours
at mid-northern latitudes. The celestial action Tuesday peaked when Jupiter and Venus lined up just 3 degrees apart in the night sky. (Your clenched fist held at arm's length measures about 10 degrees).
The show is not over, however. While the two bright planets have now begun moving away from each other in the sky, they'll remain quite close together for the next several days. [ Great Skywatcher Photos of Venus and Jupiter ]
Venus-Jupiter conjunctions are fairly special events, occurring roughly every 13 months. This year's was especially stunning, experts say, because the two planets were visible for so long in the sky and appeared so bright.
Though Jupiter is about 11 times wider than the roughly Earth-size Venus, Venus appears about eight times more luminous these days. That's because Venus is so much closer to us than Jupiter is. On average, Earth orbits 93 million miles (150 million kilometers) from the sun, a distance defined as 1 astronomical unit (AU). Venus zips around our star at about 0.72 AU, while Jupiter is found roughly 5.2 AU from the sun.
So while the two planets appear close together in the night sky, in reality they're nowhere near each other. The orbits of Venus and Jupiter are separated by Earth, Mars and the main asteroid belt.
Though Venus has now wrapped up its celestial dance with Jupiter, it will provide another skywatching treat in just a few months. On June 5, Venus will cross the face of the sun from Earth's perspective, appearing as a tiny black dot against the face of our star.
Such Venus transits occur fewer than two times per century, on average. After June 5, the next one will take place in 2117.
http://www.msnbc.msn.com/id/46734632/ns/technology_and_science-space/#.T2FCs_W8GSq
No comments:
Post a Comment