THE HEAVENS FOR DECEMBER 



207 



The Heavens in December. 



BY PROF.. ERIC DOOUTTLK OE Till- UNI- 

 VERSITY OF PENNSYLVANIA. 



The most interesting- object in the 

 heavens this month is undoubtedly the 

 beautiful planet Venus, which with its 

 extraordinary brightness and the rapi- 

 dity with which it climbs up through 

 the evening sky, will at once attract the 

 attention of every observer. For many 

 weeks we have seen this silvery-white 

 world shining out in the southwest just 

 after sunset, and throughout this time 

 it was easy to see that it was drawing 

 rapidly eastward from the sun. On 

 November 7 it passed Jupiter in its 

 eastward motion ; in less than a week 

 the apparent distance between the two 

 worlds had increased to eight degrees 

 and by the end of the month they were 

 not less than twenty-five degrees apart. 

 But all this time the brighter planet 

 was moving rapidly southward among 

 the stars, so that we saw it set con- 

 tinually farther and farther toward the 

 south point of the horizon. On Novem- 

 ber 20 it had reached a position more 

 than twenty-five degrees below the 

 celestial equator, which is nearly two 

 degrees lower than our sun ever gets 

 in the sky, but after this date it began 

 to move slowly northward again. 



THE PLANET VENUS. 



During the first days of December 

 Venus will be seen shining in the 

 southwest for more than two hours 

 after sunset, while by the end of the 

 month it will not set until three and 

 one-half hours after sunset. At this 

 time during the early evening hours 

 it will be high in the evening sky, 

 where it will pour out 25 times as much 

 light as the planet Saturn and exceed 

 by more than 2\ times the brightness 

 of Vega, which is our brightest north- 

 ern star. 



In the telescope Venus now has the 

 appearance of a bright little moon, 

 slightly more than half full. The 

 round edge of the ball is very brilliant ; 



as we approach the line which sepa- 

 rates the day side from the night side 

 of tlie planet the surface becomes much 

 darker. Yet it is universally recog- 

 nized that this world is always sur- 

 rounded by so dense an atmosphere 

 that we have never been able to pene- 

 trate with our telescopes to the solid 

 ground below. If there are any living- 

 creatures on this world it is doubtful 

 whether they ever see the sun or stars, 

 for their skies are always cloudy. 



All apparent markings which have 

 hitherto been observed on Venus are 

 almost certainly merely cloud forma- 

 tions. Yet Venus is of the highest 

 interest to us because it is more nearly 

 in the condition of our earth than any 

 other heavenly body of which we have 

 any knowledge. It'is of almost exactly 

 the same size, it is nearly of the same 

 weight, and most important of all, it 

 has a heavy and wet atmosphere, which 

 it is reasonable to suppose is warmer 

 than our own. It is not impossible 

 that the seas and lands of this tropic 

 world are swarming with life, but of 

 this we are, of course, by no means 

 certain. 



THE DECEMBER STARS. 



Though the presence of the beautiful 

 Venus leads us to turn first to the wes- 

 tern heavens, there is much in the op- 

 posite part of the sky to attract our at- 

 tention. Here, for the first time since 

 last winter, we see the bright Dog- 

 Stars just emerging from the ground, 

 while the very brilliant winter groups 

 of Orion, the Twins and the Bull are 

 shining high above them. The Greater 

 Dog Star, Sirius, a winter star and the 

 brightest star of the entire heavens, al- 

 ways enters our sky just as the bright 

 summer star, Vega, is leaving it. This 

 month for a few weeks we may see 

 both of these stars in the evening 

 heavens together. 



The Lesser Dog Star, Procyon, is 

 farther away from us than Sirius, and 

 nearly twice as large; the light of 



