Outer Space Object Is a Cookie-shaped Part of a Planet

Arizona State University astronomers¹ reported earlier this month that the strange 45-meter object appears to be made of frozen nitrogen.

The study's writers, Alan Jackson and Steven Desch, think a powerful force knocked a piece off an icy nitrogen-covered planet 500 million years ago. The piece was pushed out of its own star system toward ours. The reddish object is believed to be much different than its original self, with outer parts greatly affected² by radiation and the sun.

The object is called Oumuamua, a Hawaiian word that means "messenger from afar." It is named for the observatory³ in Hawaii that discovered it in 2017.

Oumuamua was first seen as only a small bit of light millions of kilometers away. It was found to have come from beyond our solar system because its speed and path suggested it was not orbiting the sun or anything else.

The only other object confirmed to have come from another star system into our own is the comet 2I/Borisov, discovered in 2019.

Oumuamua looked like an asteroid⁴ but sped along like a comet. Unlike a comet, however, it did not have a visible tail. Scientists could not agree on whether it was an asteroid or a comet. Some even suggested it may have been linked to alien life.

"Everybody is interested in aliens, and it was inevitable⁵ that this first object outside the solar system would make people think of aliens," Desch said in a statement. "But it's important in science not to jump to conclusions."

Jackson and Desch created computer models that helped them find that Oumuamua was most likely a piece of nitrogen ice. They also found that the object was being slowly worn down over time.

Their two papers were published by the American Geophysical Union. They were also presented at the Lunar and Planetary Sciences Conference, which was held online earlier this year.

When Oumuamua was closest to Earth, it appeared to have a width six times larger than its thickness. That is about the same as one half of an Oreo cookie, Desch noted⁶.

Oumuamua is now more than 3.2 billion kilometers away and too small to be seen, even by the Hubble Space Telescope. As a result, Jackson said, astronomers will need to depend on the original observations to continue studying it.

Desch noted that the object will continue to become thinner as it moves through space. He said in an email that by the time Oumuamua starts leaving our solar system around 2040, it will be "as flat as a pancake."

Words in This Story

original – adj. existing since the beginning

asteroid – n. a space rock, either small or the size of a large moon, that orbits the sun

comet – n. an outer space object made of material like gas and ice which is left behind in its orbit as it approaches the sun

inevitable – adj. something that cannot be avoided or prevented

jump to conclusions – v. to guess the facts about a situation without having a lot of information

pancake – n. a thin, flat bread-like food that is cooked in a pan

1 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

2 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

3 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。

4 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

5 inevitable   

adj.不可避免的，必然发生的

参考例句：

• Mary was wearing her inevitable large hat.玛丽戴着她总是戴的那顶大帽子。
• The defeat had inevitable consequences for British policy.战败对英国政策不可避免地产生了影响。

6 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。