雅思阅读 106: Defending Earth from Asteroids

Adapted from 'Will humanity be able to protect Earth from a deadly asteroid?', Scientific American, June 2026.

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Reading Passage

In late May, residents across Massachusetts saw a brilliant flash in the sky, followed by two sonic booms that rattled windows. The true source was out of this world: a small meteoroid, about five feet wide and as heavy as an elephant, had entered the atmosphere at 42,000 miles per hour before disintegrating. The midair explosion released energy equivalent to 230 to 300 tons of TNT.

Our solar system is a celestial shooting gallery, chock-full of flying projectiles, and Earth is right in the firing line. Earlier in May, the newly discovered asteroid 2026 JH2, estimated at 50 to 115 feet wide, missed Earth by a mere 56,000 miles. Had it been on a collision course, it could have destroyed a big city.

But even that is not the worst scenario. Some celestial Goliaths can be miles across, large enough to decimate entire continents. The question is not if we will suffer a direct hit but when.

If we want to protect ourselves, we should focus on medium-sized objects, from about 100 yards to half a mile. Earth is hit by a 400-yard asteroid on average once every 100,000 years. If such a collision occurred in Europe, France could disappear completely.

In 2002, astronomer Piet Hut co-founded the B612 Foundation, a private nonprofit researching how to deflect approaching celestial bodies. NASA has its own Planetary Defense Coordination Office. In 2022, NASAs DART spacecraft intentionally slammed into the asteroid Dimorphos, successfully changing its orbit.

Blowing an asteroid up with a nuclear bomb is not smart: fragments would still strike Earth. A better approach is to slightly deflect it over many years. Even a tiny change in speed of a few micrometers per second can prevent disaster.

The HAMMER project at Lawrence Livermore National Laboratory is a celestial battering ram, weighing nine tons, that can be fired at high velocity. With 10 years warning, it could deflect a 100-yard object. For larger threats, you send dozens of HAMMERs.

A cheaper method is the gravity tractor: a heavy space probe flies alongside an asteroid for years and slowly drags it off course. Other ideas include focusing sunlight to evaporate surface material, wrapping the asteroid in reflective foil, or using laser cannons.

But political obstacles remain: would Russia and China help pay to save Dallas? The same deflection technology could be turned into a weapon. Nevertheless, experts say we must identify the danger, study countermeasures and be ready.

Questions 1-5

Choose the correct letter, A, B, C or D.

1. How heavy was the Massachusetts meteoroid? A. As heavy as a car B. As heavy as an elephant C. As heavy as a mountain D. As heavy as a person
2. What size of object should we focus on? A. Dust particles B. Medium-sized, 100 yards to half a mile C. Only city-killers D. Only giant comets
3. What did DART do in 2022? A. Blew up an asteroid B. Slammed into Dimorphos and changed its orbit C. Visited Mars D. Landed on the moon
4. Why is blowing up an asteroid with a bomb a bad idea? A. It is too expensive B. Fragments would still hit Earth C. It would cause radiation D. It takes too long
5. What is a gravity tractor? A. A nuclear bomb B. A heavy probe flying alongside and pulling an asteroid C. A giant laser D. A rocket on the asteroid

Questions 6-10

Do the following statements agree with the information? Write TRUE, FALSE or NOT GIVEN.

6. Asteroid 2026 JH2 hit Earth in May.
7. The B612 Foundation was founded in 2002.
8. A tiny change in speed can deflect an asteroid.
9. HAMMER is a crewed spacecraft.
10. Planetary defense has no political challenges.

Questions 11-13

Complete the summary. Choose ONE WORD ONLY.

Instead of blowing up an asteroid, experts prefer to 11 it slightly over years. DART successfully changed the 12 of Dimorphos. The gravity tractor uses a heavy 13 flying alongside the object.

Answers

1. B 2. B 3. B 4. B 5. B
2. FALSE 7. TRUE 8. TRUE 9. FALSE 10. FALSE
3. deflect 12. orbit 13. probe

Key Vocabulary

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