Our Earth and Its Fellow Planets [391 



while before the sun, and we know it as the "morning star." 

 Mercury requires eighty-eight days to complete its trip around 

 the sun. 



Venus Most Brilliant of the Planets 



This planet, named by the ancients for their goddess of beauty, 

 is also close to the sun, but it shines with remarkable brilliance. In 

 fact, aside from the moon, Venus is the brightest object in the 

 night sky. It is invisible for certain periods, like Mercury; but 

 these periods of invisibility are far less frequent than Mercury's. 

 We can hope to see Venus about sunset or dawn, and occasionally 

 we can see it, with the naked eye, in broad daylight. 



THE ATMOSPHERE OF VENUS 



Venus has an atmosphere, and in fact it is completely 

 covered by dense white clouds one reason for its brilliance, as 

 the clouds reflect light. Unfortunately the clouds hide all fixed 

 points on the planet, so we do not know what its surface is like. 

 Astronomers have not detected oxygen and water vapor in the 

 upper atmosphere of Venus a fact which leads us to conclude 

 that life does not exist there. However, we do not know what 

 conditions exist below the heavy surrounding curtain of clouds. 

 With a small telescope you can watch Venus go through phases 

 similar to those of the moon. When it is nearest to the earth it 

 appears as a crescent; when the planet is farthest from the earth 

 it is "full." 



Earth Just Another Planet 



With solid ground under his feet, and firmly rooted trees, 

 solidly constructed buildings, and many other stationary objects 

 all about him, a child finds it difficult to think of our earth as a 

 heavenly body moving freely through space, just like the other 

 planets. Probably the most convincing evidence you can offer the 

 youngster to show that we do live on a moving planet is to cite 

 our change of seasons and alternating periods of light and 

 darkness. 



