VOA科学技术2025--Space Agencies Report Increased Risk of Space Rock Striking Earth in 2032

（单词翻译）

Scientists say the threat of a large space rock striking the Earth in 2032 has increased.

Recent calculations suggest there is a small chance - perhaps around 1 to 3 percent - the space rock 2024 YR4 will hit Earth in 2032. This also means there is around a 97 to 99 percent chance it will safely pass our planet in that year. The odds¹ of a strike will likely continue to go up and down as the asteroid²'s path around the sun is better understood.

And scientists say there is a good chance the risk will drop to zero.

NASA and the European Space Agency's Webb Space Telescope will observe this near-Earth asteroid in March before the object becomes impossible to see. Once that happens, scientists will have to wait until 2028 when it passes our way again.

What is an asteroid?

Asteroids³ are space rocks orbiting the sun.

Asteroids are much smaller than planets. Scientists believe they are the leftovers⁴ from the solar system's formation 4.6 billion years ago.

There are millions of asteroids orbiting the sun between Mars and Jupiter. That area is known as the main asteroid belt. The asteroids sometimes get pushed out of the belt and can end up elsewhere.

How do scientists follow worrisome asteroids?

A telescope in Chile discovered the asteroid 2024 YR4 in late December. It is estimated to measure between 40 and 90 meters across. NASA said observations by the Webb space telescope should provide a more exact measurement.

At first, NASA and the European Space Agency put the odds of a strike at just over one percent. But later calculations suggested the odds had risen to 2 or even 3 percent. NASA described the likelihood of a strike as "extremely low."

Until scientists have a better understanding of the asteroid's path around the sun, they warned that the odds will continue to change - and quite possibly fall to zero.

"You don't have to be worried about anything. It's a curiosity," said Larry Denneau. He is a software engineer at the University of Hawaii working with ATLAS⁵, a program to identify asteroids that might endanger Earth. That effort first spotted⁶ the asteroid. Denneau said, "Don't panic. Let the process play out, and we'll have a for-sure answer."

In 2021, NASA said another possibly worrisome asteroid, Apophis, did not present a risk to Earth. NASA made the announcement after additional telescope observations ruled out any chance of it hitting Earth in 2068.

Should we worry about asteroid 2024 YR4?

Experts say it is too soon to worry about 2024 YR4.

Paul Chodas is director of NASA's Center for Near-Earth Object Studies. Chodas said in an email to the Associated Press, "No one should be concerned that the impact probability is rising. This is the behavior our team expected."

Chodas added, "To be clear, we expect the impact probability to drop to zero at some point."

Since the asteroid's size and orbit are uncertain, it is unclear where it might hit and what the possible effects would be should it strike Earth. ESA said, if the asteroid is smaller, the effect might be similar to the Tunguska event that flattened⁷ thousands of square kilometers of forest in Siberia in 1908. But if the asteroid is larger, close to 100 meters, the effects "would be significantly worse."

Chodas said once the Webb telescope measures the asteroid's size, NASA can predict "how serious an impact this asteroid could produce and how difficult a task it might be to deflect⁸ this asteroid."

NASA already has some experience moving an asteroid. The space agency's Dart⁹ spacecraft hit a harmless asteroid in 2022. This was the first planetary defense¹⁰ test of its kind, changing the asteroid's orbit around its larger companion asteroid.

I'm John Russell.

Marcia Dunn reported this story for the Associated Press. John Russell adapted it for VOA Learning English.

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Words in This Story

odds -n. (pl.) the likelihood that something will happen

curiosity -n. a strong desire to learn more about something

panic - v. to be overcome with a powerful fear

probability-n. the chance that an event will occur

impact -n. an event in which one object strikes or crashes into another

significantly - adv. in a major way

deflect -v. to cause an object to move in another direction possibly by striking it and changing its path a little

companion-n. an object that is closely connected to another, usually by gravity