马斯克的一枚火箭残骸将于3月撞上月球

Scientists say the remains of a rocket used to help deploy a satellite in 2015 is on a path to strike the moon in early March.

The object was used to boost a SpaceX Falcon 9 rocket during its second stage of flight. Such leftover parts from spacecraft and equipment are known as space junk.

The path of the rocket remains was first observed by American Bill Gray. He is an astronomer and the creator of Project Pluto, based in the northern U.S. state of Maine. He develops and sells software that can track the path of different space objects, including space junk.

Gray has been publishing information about the object's path toward the moon on a website. He says his information is based on his own observations as well as those gathered from others.

He writes that the object weighs about four tons and will strike the moon at a speed of 2.58 kilometers per second. Gray says all his data shows that the rocket will hit the far side of the moon on March 4, at 12:25 Universal Time. The far side of the moon faces away from Earth.

The expected strike has also been confirmed by astrophysicist Jonathan McDowell, as well as the U.S. space agency NASA. McDowell is with the Center for Astrophysics, which is jointly operated by Harvard University in Massachusetts and the Smithsonian Institution.

McDowell writes in an online statement that, in the past, "lots of junk from lunar missions has ended up hitting the moon." But he notes that this "is the first time that something not explicitly targeted at the moon has been noticed to accidentally hit it." McDowell noted on Twitter that he finds the expected strike "interesting, but not a big deal."

Gray agreed and said the moon is regularly hit with larger objects moving faster than the remains of the SpaceX rocket. That, he notes, is how the moon got all its craters. "It's well built to take that sort of abuse," Gray writes.

McDowell said there are about 30 to 50 "lost deep space objects" like the SpaceX booster that have long been missing, some as old as 50 years. He added, "Probably some of them hit the moon without us noticing."

McDowell said the remains of the SpaceX rocket is just one example of the growing problem and possible dangers of space junk. "I think it's time for the world to get more serious about regulating and cataloging deep space activity," he wrote.

A NASA spokeswoman told the French Press Agency, AFP, that the space agency sees the expected strike as "an exciting research opportunity." But she said it might be difficult and take "weeks to months" to find the crater that is created.

This is because the strike cannot be seen from Earth in real time. Also, NASA's Lunar Reconnaissance Orbiter – which is currently orbiting the moon – will not be in a position to observe the hit as it happens, the spokeswoman said.

In the past, spacecraft have been crashed into the moon on purpose for scientific experiments. But this is likely the first unplanned strike to be identified in this way.

Gray thinks space junk should be directed toward the moon whenever possible. "If it hits the moon, then we actually learn something from it," he said.

I'm Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on a report from Agence France-Presse and information from Project Pluto and Jonathan McDowell.

boost – v. to push or shove up from below

track – v. to record the progress of development of something

explicit – adj. clear and exact

notice – v. to see something and be aware of it

crater – n. a round hole made by an explosive force such as a bomb or an object falling from the sky

regulate – v. to control an activity or process, especially by using rules

catalog – v. to make a list of things, especially in order to put it in a catalog

opportunity – n. a situation in which it is possible for a person to do something

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