These mechanical devices that show the relative placement and movement of the planets and moons are sometimes called orreries.

VOA: special.2010.09.29

Look, take the argument of the planets, the Morning Star and the Evening Star example.

拿行星的论证,晨星和昏星的那个例子来说

耶鲁公开课 - 死亡课程节选

By putting the two together, out comes the elliptical motion of the planets.

将这两个式子联立,就得到了行星作椭圆运动的方程

耶鲁公开课 - 基础物理课程节选

Scientists say extensive observations from earth-based telescopes are needed to confirm the existence of the planets.

VOA: special.2011.02.09

In fact, there's a property of gravitational fields anywhere, even in outer space, but there is some residual field between all the planets and all the stars in the universe, that the force on a body is proportional to the mass of the body.

实际上,这是任何地方的引力场都具备的属性,甚至是在外太空,在所有的行星和恒星之间,存在着某种剩余场,在这个场里作用在物体上的力,和物体的质量之间存在比例关系

耶鲁公开课 - 基础物理课程节选

Yale University astronomer Debra Fischer says non-professional astronomers around the world are helping study the new information about the possible planets.

VOA: special.2011.02.09

NASA scientists using the Kepler space telescope also announced the discovery of six planets orbiting a star called Kepler-11.

VOA: special.2011.02.09

A planetarium is a theater with a rounded ceiling onto which images of the stars and planets are projected.

VOA: special.2010.09.29

We will also tell about a historic record of rainy seasons in Asia, and the search for life on other planets.

VOA: special.2010.05.25

Some scientists have called Jupiter the protector of the inner planets and our own Earth -- from objects from the outer solar system.

VOA: special.2009.08.25

The Kepler space telescope looks for planets by measuring tiny decreases in the brightness of stars when planets cross in front of them.

VOA: special.2011.02.09

And what does that mean? It means I am trained in geology, but with interests in the other planets and Mars in particular."

VOA: special.2010.07.28

Historians say the Italian scientist and mathematician may not have been the first to get a good look at the moon and planets.

VOA: special.2009.10.27

NASA scientists say the Earth-like planets are among one thousand two hundred thirty-five possible planets orbiting other stars that have been discovered so far.

VOA: special.2011.02.09

Mr.Lissauer says the five inner planets are among the smallest confirmed planets beyond our solar system.

VOA: special.2011.02.09

But the Kepler mission's chief scientist, William Borucki,says eighty percent of the possible planets will probably be confirmed in the coming months and years.

VOA: special.2011.02.09

Or Venus? Or on any of the other planets either inside or outside our solar system?

VOA: special.2010.05.25

Still another is the crash of large asteroids, minor planets that fall to earth.

VOA: special.2009.03.17