Have you have heard anyone call Venus the evening star? It could also be called the morning star and so could Mercury. If you carefully search the sky, especiallywith binoculars, you should be able to see both of them if you look at just the right height above the horizon. Venus sets higher in the western sky than Mercury. Eventually, both of these planets will drop lower each day, until you can't see them at all. A little while later you will find them in the eastern sky in the early morning. Because the planets drop out of view you will never see all the phases of these planets.

Like a Sister

Are you a lot like the other people in your family? Astronomers used to think of Venus as the Earth's sisterplanet, mainly because they were about the same size and weight. If Earth seems to be an ideal planet, Venus would have to be the opposite. Why are they so different? Well, for starters, its bright light is caused by the reflection from its clouds. Unlike Earth's clouds, Venus's are made from sulfur that is floating in its atmosphere filled with heat-trapped carbon dioxide. On Earth, volcanoes helped to create oxygen. On Venus, volcanic gas creates a sulfuric acid rain. This rain is carried by winds that travel hundreds of miles per hour. Because of this harsh environment, space probes that were sent to investigate Venus didn't last long. The probes melted, were dissolved in acid, or were crushed by an atmospheric pressure that is almost one hundred times as heavy as Earth's! Could anythingever live there? To answer this question the probes were designed to send back pictures. The pictures showed raised areas that looked like continents, which left many scientistswondering if Venus ever had oceans. It is probably just as well that the astronauts haven't made it to Venus. Can you imagine living on a planet where the sun rises in the west? And if you think that would be weird, imagine staying in a place where there are less than two days in a year?

Venus Is Coming Up on the Inside!

Venus is not only similar to Earth in shape and size, but it is also the closest planet to Earth. Even though Venus spins backward as it rotates, it still orbits the sun in the same direction as the rest of the planets. All the planets in our solar system orbit the sun like racecars going around a track. Like racecars, planets don't orbit in a perfect circle, either. Hundreds of years ago, after astronomers finally admitted that the sun was the center of the solar system, they had a new mystery to solve. Somehow they wanted to figure out why the planets appeared to speed up and slow as they circled the sun. One day a scientistnamed Kepler developed a set of laws that seemed to provide the answers. The orbits were ellipses, so at times the planets were closer to the sun. As the planets near the sun they slow down and then speed up as they move away. A planet that is close to the sun takes much less time to complete an orbit. How long does it take for each planet to orbit the sun?

Go Mercury!

In Roman mythology, Mercury carried messages between the gods and goddesses, and was often pictured with wings on his hat and on his sandals.

Why did astronomers name the planet Mercury after this speedy messenger? See how quickly you can break the Vowel Shift Code to learn the answer!

• Mercury takes almost 88 days; Venus takes almost three times as long at 224 days.

• Everyone knows Earth's orbit takes 365 days, but Mars needs about twice that time to make an orbit at around 680 days.

• Jupiter takes close to 12 years and Saturn takes almost 30 years.

• It takes about 85 years before Uranus returns to its originalplace in space while Neptune doubles its orbit time at roughly 165 years.

• Tiny Pluto takes about 250 years to circle the sun!

Unlike racecars, the planets don't really bunch up as they round the track. If you want to see their orbits, type “Solar System Viewer” in your search box on the Internet to see it.