DOUBLE STARS.

“That wonderful tell-tale, the ‘telescope,’ reveals the double character of some stars,” said Mr. Marple. “There are six thousand stars which are thus double.

That is singular.

[Pg 55]There are some in the Pleiades, in the Dog, in Orion, and in the Southern Cross and Crown. But the most wonderful part of my story is yet to come. Some of these double stars revolve¹ round each other.

What! Great suns at a tremendous distance from one another, walk round one another? Why, if they have planets round them, like our sun has, these must have a fine double journey to make. How many of these strange stars are there?

About 650 of them are Binary² or revolving³.

But which stands still to have the other revolving round it?

They both move, each one round the other.

A regular polka in the heavens, father. And yet I suppose they are not just like a gentleman and his lady partner.

I don’t know that; for it has been observed that a number have different colours to their companions. While one is blue, the other will be yellow. One shall be green, and its mate will be orange. One-half are white, and one-tenth are both blue.

That does please me. How I should like to be in a planet where my sun should be blue, and its companion sun red. It would be so funny to get up in the morning and see my sun blue, throwing a blue tint⁴ on everything. Then, when the other sun rose, a rich red would steal over the blue, and change everything. But when the blue sun had set, the red one would have it all its own way, and bathe my world in its ruddy light.

[Pg 56]That fancy is good, and not very improbable either; especially if the other sun should come pretty near your sun at times, as it is likely they move in an ellipse.

Can you tell me, dear father, how long these pleasant binary stars take in performing their polka?

One in Hercules takes thirty-one years. In our old Great Bear, a binary pair take sixty-one, and in Leo eighty-two. In the Swan we have 178 years, and in the Virgin⁵ 182. In the Crown we have two several times given of 608 and 736 years. It is believed that one pair are 1200 years. The North Polar Star is double, and is thought by some to revolve in 6000 years.

Please, father, tell me some more about the colours of the double folk.

The Polar double stars are red and white. In Scorpion⁶, there is a white one and a lilac one; in the Centaur⁷, we have both orange; in Andromeda, crimson⁸ and green; in the Lion, gold and green; in one of Scorpio, White and plum; in Castor, yellow and green; in Antares, both are bright red; Arcturus was all red in 1841, and yellow in 1852.

I wonder how far these partners are from each other.

That is difficult to ascertain⁹. The binary stars of the Swan are thought to take 450 years going their circuit, and yet to be billions of miles away from each other.

There is little danger of quarrelling at that distance apart, father.

[Pg 57]Astronomers talk of stars running against one another. There are also triple stars.

Three stars polkaing in and around each other! That is odd. Where are there any?

In the Lyre and Scorpion. In the latter the colours are white, grey, and yellow. In the Swan the largest star is very yellow, and its two mates are blue. But more wonderful still, in Orion there are four stars thus rolling round each other.”

1 revolve   

vi.(使)旋转；循环出现

参考例句：

• The planets revolve around the sun.行星绕着太阳运转。
• The wheels began to revolve slowly.车轮开始慢慢转动。

2 binary   

adj.二，双；二进制的；n.双(体)；联星

参考例句：

• Computers operate using binary numbers.计算机运行运用二进位制。
• Let us try converting the number itself to binary.我们试一试，把这个数本身变成二进制数。

3 revolving   

adj.旋转的，轮转式的；循环的v.（使）旋转( revolve的现在分词 )；细想

参考例句：

• The theatre has a revolving stage. 剧院有一个旋转舞台。
• The company became a revolving-door workplace. 这家公司成了工作的中转站。

4 tint   

n.淡色，浅色；染发剂；vt.着以淡淡的颜色

参考例句：

• You can't get up that naturalness and artless rosy tint in after days.你今后不再会有这种自然和朴实无华的红润脸色。
• She gave me instructions on how to apply the tint.她告诉我如何使用染发剂。

5 virgin   

n.处女，未婚女子；adj.未经使用的；未经开发的

参考例句：

• Have you ever been to a virgin forest?你去过原始森林吗？
• There are vast expanses of virgin land in the remote regions.在边远地区有大片大片未开垦的土地。

6 scorpion   

n.蝎子，心黑的人，蝎子鞭

参考例句：

• The scorpion has a sting that can be deadly.蝎子有可以致命的螫针。
• The scorpion has a sting that can be deadly.蝎子有可以致命的螫针。

7 centaur   

n.人首马身的怪物

参考例句：

• His face reminded me somehow of a centaur.他的脸使我想起半人半马的怪物。
• No wonder he had soon been hustled away to centaur school.也难怪父母匆匆忙忙就把他送到了半人马学校。

8 crimson   

n./adj.深(绯)红色(的)；vi.脸变绯红色

参考例句：

• She went crimson with embarrassment.她羞得满脸通红。
• Maple leaves have turned crimson.枫叶已经红了。

9 ascertain   

vt.发现，确定，查明，弄清

参考例句：

• It's difficult to ascertain the coal deposits.煤储量很难探明。
• We must ascertain the responsibility in light of different situtations.我们必须根据不同情况判定责任。