美国有线新闻 CNN 科学争论再起 将行星身份还给冥王星

 

Which of these is not a requirement for a celestial¹ body to be considered a planet? Must orbit the sun, must clear its path of orbit, must have a moon or must be round. A planet does not need a moon to meet the International Astronomical² Union’s definition of a planet.

But as option B indicated, it does have to clear the neighborhood in its path of orbit. Meaning knock other space rocks out of the way if necessary and that's why the International Astronomical Union announced in 2006 that Pluto³ was no longer a planet. The Union said it was just too small to clear its path. But that decision caused a lot of controversy⁴ and not just among those who were taught there were nine planets in our solar system.

New research published in the scientific journal Icarus argues that Pluto should be reinstated to planetary status. A University of Central Florida scientist says that, nobody actually uses the path clearing requirement in their research.

He says his team looked at two centuries worth of materials and found only one study from the early 1800's that used the path clearing requirement.

He adds that the way a celestial body is formed and whether it's big enough to have a spherical⁵ shape are more important factors for its classification. The IAU says it hasn't received any formal requests to reevaluate Pluto but that it's good to debate these topics.

1 celestial   

adj.天体的；天上的

参考例句：

• The rosy light yet beamed like a celestial dawn.玫瑰色的红光依然象天上的朝霞一样绚丽。
• Gravity governs the motions of celestial bodies.万有引力控制着天体的运动。

2 astronomical   

adj.天文学的，（数字）极大的

参考例句：

• He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
• Houses in the village are selling for astronomical prices.乡村的房价正在飙升。

3 Pluto   

n.冥王星

参考例句：

• Pluto is the furthest planet from the sun.冥王星是离太阳最远的行星。
• Pluto has an elliptic orbit.冥王星的轨道是椭圆形的。

4 controversy   

n.争论，辩论，争吵

参考例句：

• That is a fact beyond controversy.那是一个无可争论的事实。
• We ran the risk of becoming the butt of every controversy.我们要冒使自己在所有的纷争中都成为众矢之的的风险。

5 spherical   

adj.球形的；球面的

参考例句：

• The Earth is a nearly spherical planet.地球是一个近似球体的行星。
• Many engineers shy away from spherical projection methods.许多工程师对球面投影法有畏难情绪。