Recent Asteroid Flyby Suggests ‘Blind Spot’ in Planetary Defense

Recent Asteroid¹ Flyby Suggests ‘Blind Spot’ in Planetary Defense²

A small asteroid was discovered recently, just days before it passed close to Earth. The object was never considered a real threat to our planet. But the discovery has raised questions about whether current systems used to identify possibly threatening objects might leave a blind spot for some objects.

NASA and its international partners continuously search the skies for what scientists call near-Earth objects. Such objects include asteroids³ and comets that come within 50 million kilometers of Earth's orbit.

The American space agency NASA announced January 25 that an asteroid about the size of a large truck would pass very close to Earth the very next day. The agency said the object, called 2023 BU, was expected to make one of the closest trips past Earth ever recorded.

NASA said the asteroid was discovered January 21 by an amateur astronomer⁴ based in the Russian-occupied Ukrainian territory of Crimea. The astronomer, Gennady Borisov, is a telescope maker⁵ and operates his own observatory⁶. He is credited with discovering an interstellar comet in 2019.

Additional observations of 2023 BU were then reported to an internationally recognized organization, the Minor⁷ Planet Center, which records the current positions of near-Earth objects. The data was added to the Near-Earth Object Confirmation⁸ Page.

NASA said that in the days leading up to the asteroid's flyby, a number of observatories⁹ around the world were able to confirm the position of the object. This helped astronomers¹⁰ follow 2023 BU's orbit.

Davide Farnocchia is an engineer and planetary defense expert at NASA's Jet Propulsion Laboratory in California. He said in a statement that the agency was quickly able to rule out an asteroid strike.

NASA said the asteroid passed within 3,600 kilometers of Earth, above the southern tip of South America. That distance is 10 times closer than numerous satellites orbiting Earth.

Scientists said that even if the space rock came a lot closer to Earth, it would have burned up in the atmosphere. In that case, a few bigger pieces might have fallen to Earth as meteorites¹¹.

In general, NASA believes the probability of Earth being struck by a space rock is very low. Astronomers estimate that a space rock of 5-meters in length targets Earth once a year. And a 50-meter rock is estimated to target Earth once every 1,000 years.

But existing systems used to identify near-Earth objects have difficulty finding smaller ones. Asteroid 2023 BU was on the smaller end of a grouping of objects between 5 to 50 meters. Scientists say objects that size are difficult to identify until they get much closer to Earth. This makes it difficult to prepare for an object that might be heading for a populated area.

"We don't know where most of the asteroids are that can cause local to regional devastation," Terik Daly told Reuters news agency. He is a planetary scientist at the Johns Hopkins Applied¹² Physics Laboratory in Maryland.

Some astronomers have proposed using new tools to identify near-Earth objects rather than depending on probability estimates and existing asteroid populations.

Daly noted¹³ that new identification tools could help scientists deal with a possibly dangerous asteroid event. "How many natural hazards are there that we could actually do something about and prevent for a billion dollars? There's not many," he said.

NASA is already planning to launch a new infrared¹⁴ space telescope designed to support current planetary defense efforts. The Near-Earth Object Surveyor is currently still in development and is set to launch in 2026. NASA officials have said the telescope promises a major improvement over existing ground-based models limited by daytime light and the effects of Earth's atmosphere.

Last year, NASA carried out the first-ever planetary defense test when it crashed a spacecraft into an asteroid. The test successfully changed the path of an asteroid named Dimorphos.

Words in This Story

asteroid – n. a rocky object that goes around the sun like a planet

comet – n. an object in space that leaves a bright line behind it in the sky

amateur – n. someone who does something for fun and not as a job

regional – adj. of, or related to, a region

devastate¹⁵ – v. to damage badly or destroy something

hazard – n. something dangerous

1 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。

2 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

3 asteroids   

n.小行星( asteroid的名词复数 )；海盘车，海星

参考例句：

• Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
• Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。

4 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。

5 maker   

n.制造者，制造商

参考例句：

• He is a trouble maker，You must be distant with him.他是个捣蛋鬼，你不要跟他在一起。
• A cabinet maker must be a master craftsman.家具木工必须是技艺高超的手艺人。

6 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。

7 minor   

adj.较小(少)的，较次要的；n.辅修学科；vi.辅修

参考例句：

• The young actor was given a minor part in the new play.年轻的男演员在这出新戏里被分派担任一个小角色。
• I gave him a minor share of my wealth.我把小部分财产给了他。

8 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

9 observatories   

n.天文台，气象台( observatory的名词复数 )

参考例句：

• John Heilbron, The Sun in the Church: Cathedrals as Solar Observatories, 3-23. 约翰．海耳布隆，《教会里的太阳：教堂即太阳观测台》，第3-23页。 来自互联网
• Meteorologists use satellites, land observatories and historical data to provide information about the weather. 气象学家使用卫星、上天文台和历史资料来提供有关天气的信息。 来自互联网

10 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》

11 meteorites   

n.陨星( meteorite的名词复数 )

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》

12 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

13 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。

14 infrared   

adj./n.红外线(的)

参考例句：

• Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
• Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。

15 devastate   

v.使荒芜，破坏，压倒

参考例句：

• A few days before,a fire had devastated large parts of Windsor Castle.几天前，温莎城堡的大部分被一场大火烧毁。
• Earthquakes can also cause tsunamis,which devastate coastal regions.地震还引发海啸，它直接破坏海岸地区。