— VOA Learning English — Science & Technology Source: Voice of America Learning English (https://learningenglish.voanews.com/) Licence: Public domain (work of the U.S. federal government, 17 U.S.C. §105) Audio is served by the publisher; Budi does not host or modify it.
0:02Astronomers following asteroid activity in space estimate there is a very small chance an object large enough to destroy a whole city could strike Earth in 2032. But Space Agency officials say even if such an asteroid keeps heading on a path toward Earth, the world is now much better equipped to defend itself against such a threat. The American space agency NASA recently estimated there was a 3.1% chance that asteroid 2024YR4 would hit Earth on December 22, 2032. That is the highest probability predicted for such a large space rock in modern times. Richard Meusel is head of the European Space Agency's Planetary Defense Office, while recognizing the risk the asteroid could present, he told the French news agency AFP
1:14people should not panic over such predictions. Astronomers have noted that, the more data they gather, the odds of a direct asteroid hit are expected to keep rising over time. However, scientists say at a certain point, the odds will likely drop down to zero. Meusel said he thinks it is important to remember that even in the unlikely event, the probability keeps rising to 100%, the world is not defenseless. Here are some methods currently being considered as defensive measures to keep humanity safe in case there is a real threat. Only one planetary defense method has been tried against an asteroid. In 2022, NASA's Double Asteroid Redirection Test sent a spacecraft into the 160-meter-wide Dimorphos asteroid.
2:17The effort successfully changed the asteroid's orbit around a larger space rock. Bruce Betts is chief scientist for the non-profit Planetary Society. He told AFP that space agencies could hit the 2024 YR4 asteroid with several spacecrafts, observing how each one changed the path. The asteroid discovered in December is estimated to be 40-90 meters wide, about half the size of Dimorphos. You have to take care not to overdo it, Weissel warned. He said this is because if a spacecraft only partially destroys an asteroid, it could send smaller pieces of the space rock heading toward Earth. A separate idea would involve sending a large spacecraft to fly alongside a threatening asteroid. The spacecraft would not touch the asteroid, but would use its gravitational force to pull
3:20it away from Earth. Moisel said another non-contact plan would put a spacecraft near the asteroid to eject a continuous flow of atoms to push the asteroid off course. Scientists have also considered painting one side of the asteroid white. They believe this could increase the light the object reflects to make it slowly change course. One idea is to use a nuclear weapon against a threatening asteroid. In laboratory tests, researchers found that X-rays from a nuclear blast could move a rock. But this is considered more of a plan for kilometers wide asteroids, like the one that killed off the dinosaurs, and this method also carries the risk that a nuclear explosion could send additional pieces of the asteroid falling toward Earth.
4:20A similar method, but one considered less dangerous, would involve shooting laser beams from a spacecraft to destroy the side of an asteroid in an effort to push it away from Earth. Meusel said that if all else fails, at least the world will have a good idea where a threatening Asteroid would strike. Since astronomers believe most asteroids would at most threaten to destroy one city, efforts could be organized to get people out of an area before a strike. Seven and a half years is a long time to prepare," Meusel added. He also noted that even with the rising odds involving 2024 YR4, there is still about a 97% chance the asteroid will miss Earth. I'm Jill Robbins
This transcript was generated automatically from the recording, so it will contain mistakes — especially around names and places.