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Moon and Venus月球和金星

The planet Venus is now low in the west after sunset. It's not up for long after the sun goes down, but it's very, very bright. Learn how to see Venus tonight near Earth's companion moon -- today on Earth and Sky.

JB: This is Earth and Sky. Earth's ozone layer protects us from the sun's ultraviolet -- or UV, radiation. Ozone depletion has been blamed for an increase in skin cancers in human beings.

DB: And this radiation seems to have a negative effect on plants as well. Jay Skiles is a scientist at NASA's Ames Research Center in Mountain View, California.

JB: This is Earth and Sky -- Monday, September 9. The planet Venus is still up after sunset. But it's lower in the sky now than it was a month ago.

DB: Still, this is a wonderful time to see Venus if you have a clear view to the western horizon. That's because the planet is approaching what's called "greatest brilliancy" when Venus appears at its brightest in Earth's sky. And for Venus, the brightest planet, that's very brilliant indeed -- so that UFO reports always increase each time Venus reaches another greatest brilliancy in the evening sky.

JB: Greatest brilliancy for Venus will happen later this month, on September 26. But tonight is a good time to start watching this planet -- because tonight Venus is right next to the waxing crescent moon. You'll find Venus and the moon in the west after sunset. There's a little star to the lower right of Venus -- and this star is Spica in the constellation Virgo.

DB: The moon will continue to wax larger in our sky. It'll pull away from Venus in the coming evenings. But you can continue to look for Venus after sunset for about another month. In mid-to-late October this planet will disappear in the sun's glare. It'll pass between the Earth and sun on October 31 -- Halloween.

JB: A few days or weeks after that, you'll be up before the sun some morning -- and find Venus shining brightly in the predawn sky. Special thanks today to Research Corporation -- a foundation for the advancement of science. We're Block and Byrd for Earth and Sky.