VOA慢速英语--阿罗科思:有史以来最遥远的太空物体

A space object billions of kilometers away from Earth is giving scientists information about how our planet, and others, were formed.

It is the most distant object ever explored by a spacecraft. It is named Arrokoth, and sometimes called "Snowman" because of its shape.

Arrokoth is some 6.6 billion kilometers away from us. It can be found about 1.6 billion kilometers past Pluto¹, the largest dwarf² planet in our solar system.

NASA's New Horizons spacecraft flew past Arrokoth on New Year's Day, 3 years after exploring Pluto, which is located just past the planet Neptune³ in an area called the Kuiper Belt.

The New Horizons spacecraft has been providing scientists with information about the formation of Neptune and other planets.

Pictures it sent back of Arrokoth show a reddish surface. It appears to be largely smooth, with some craters—areas that are lower than their surroundings. It is covered with frozen methanol, a kind of alcohol, and unidentified complex organic molecules⁴.

Arrokoth is a small body -- 36 kilometers long and 20 kilometers wide. It is classified as a planetesimal — objects that were among the original building blocks of our solar system. Scientists believe these small bodies came together about 4.5 billion years ago. They are thought to be an important middle size step on the way to building planets.

The space object is made of two round parts joined together, notes John Spencer, an astronomer⁵ at the Southwest Research Institute in Colorado. They "appear to have formed in orbit around each other from a local dust cloud, which collapsed⁶ under its own gravity within the solar nebula⁷ - the huge disk of dust and gas that the solar system formed from," he said.

The two parts then came together "very gently." This suggests that planetesimals formed in local conditions in which crash speeds were slow, instead of widely spaced objects coming together at high speeds.

"So we now have a clearer picture of how planets, including the Earth, were built," Spencer said. He helped prepare a report on the study, which appeared in Science magazine.

When spacecraft visited planetesimals before, they were all badly damaged by objects that struck them. Some experienced extreme heat because they moved too close to the sun.

"So it is thrilling to finally be able to see one still pretty much just as it was after its formation," said Will Grundy, who is working with the New Horizons project. He is a planetary scientist and study co-author from Lowell Observatory⁸ in Arizona.

One of the scientists on the New Horizons team is better known for his music than his doctorate—an advanced degree in astrophysics. Brian May, lead guitarist for the British group Queen, is passionate⁹ about space exploration, as well as music. He wrote this song for the New Horizons project:

(Music plays)

New Horizons will examine other objects in the Kuiper Belt from afar as it makes its way deeper into space.

Words in This Story

dwarf – adj. smaller than normal size

solar system – n. our sun and the planets that move around it

building blocks – n. an important part that is grouped together with many other similar things to form something larger — usually plural¹⁰

nebula – n. a group of stars that are very far away and look like a bright cloud at night

disk – n. a flat, thin, round object

thrilling – adj. very exciting

author – n. a writer

passionate – adj. filled with emotion

1 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。

2 dwarf   

n.矮子，侏儒，矮小的动植物；vt.使…矮小

参考例句：

• The dwarf's long arms were not proportional to his height.那侏儒的长臂与他的身高不成比例。
• The dwarf shrugged his shoulders and shook his head. 矮子耸耸肩膀，摇摇头。

3 Neptune   

n.海王星

参考例句：

• Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
• Neptune turned out to be a dynamic,stormy world.海王星原来是个有生气、多风暴的世界。

4 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

5 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

6 collapsed   

adj.倒塌的

参考例句：

• Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
• The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。

7 nebula   

n.星云，喷雾剂

参考例句：

• A powerful telescope can resolve a nebula into stars.一架高性能的望远镜能从星云中分辨出星球来。
• A nebula is really a discrete mass of innumerous stars.一团星云实际上是无数星体不连续的集合体。

8 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

9 passionate   

adj.热情的，热烈的，激昂的，易动情的，易怒的，性情暴躁的

参考例句：

• He is said to be the most passionate man.据说他是最有激情的人。
• He is very passionate about the project.他对那个项目非常热心。

10 plural   

n.复数；复数形式；adj.复数的

参考例句：

• Most plural nouns in English end in's '.英语的复数名词多以s结尾。
• Here you should use plural pronoun.这里你应该用复数代词。