Musk's rocket will collide with the moon.

On January 21st, Bill Gray, a developer of astronomy research software, posted on the social platform: "The wreckage of Falcon 9 rocket weighing 4 tons will hit the back of the moon at 7: 25 (EST) on March 4th, leaving a crater 2 meters in size."

On 26th, this prediction was confirmed by mcdowell, a professor at Harvard-Smithsonian Center for Astrophysics, on Twitter: "There will indeed be an impact on March 4th."

Gray said: "Although there is some uncertainty about the time and place of collision, the collision between the rocket wreckage and the moon is inevitable. The collision will occur within a few minutes of time error and a few kilometers of distance error. "

It is reported that the Falcon 9 rocket was used by SpaceX, which was founded in elon musk, when it launched the Deep Space Climate Observatory (DSCOVR) satellite for NOAA in 215. The satellite is responsible for monitoring the solar wind from the sun so as to better predict the space weather.

Why did it hit

After the satellite was put into orbit, the rocket debris was usually sent back to the earth's atmosphere by SpaceX, and burned and disappeared due to the friction heat with the atmosphere.

But after Falcon 9 rocket sent the satellite into orbit about 1.5 million kilometers away from the Earth, it didn't have enough fuel to return to the Earth and was "abandoned" in high orbit in space. In this way, it passed through earth-moon system in a long and circular orbit for nearly seven years.

Professor mcdowell said: "Because the fuel is exhausted, the upper end of the rocket is in a state of death, and it just follows the law of gravity." "Since 215, the rocket has been dragged by the different gravitational forces of the earth, the moon and the sun, making its path chaotic."

The collision of a space object in low orbit around the Earth with the International Space Station or a satellite may cause danger, but Falcon 9 rocket was forgotten because it was very far away from the Earth, and no one was worried about it. Gray said, "I'm the only one who tracked the object."

after seven years, the aimless wandering life is finally coming to an end.

Gray said that the upper part of the rocket passed less than 1, kilometers from the moon on the 5th. Gray thought that the upper end of the rocket would pass through the orbit close to the earth, so he entrusted astronomers to observe it. Through the collected data, Gray predicts that it will be the end of its life at 7: 25 (EST) on March 4, when it will collide with the moon and explode on contact.

What are the consequences

"It's interesting, but it's no big deal," Professor mcdowell wrote on Twitter.

So far, many spaceships have hit the moon, but this is the first unplanned and unexpected collision. NASA has deliberately sent rocket parts and spacecraft to hit the moon before.

"Because the collision happened on the back of the moon, you can't see the collision from the earth. However, it is still important to determine its time and location, which can provide scientists with an opportunity to study the surface of the moon. NASA's Lunar Reconnaissance Orbiter (LRO) and India's' Moon Ship 2' are expected to observe the crater caused by the collision, "Gray wrote. The collision is expected to leave a crater of 1-2 meters on the moon.

Gray said that although there is nothing to worry about, this incident is a good reminder that we need better ways to deal with space junk.

such objects are usually abandoned in extremely long orbits around the earth. if they come back and hit us, they will come in at a faster speed and at a more perpendicular angle to the atmosphere, and some fragments are more likely to survive re-entry.

Gray said: "If they do enter and hit the earth, there is a recognized very small possibility that a small number will survive and hit the ground."

Of course, since such incidents are extremely rare, they do not pose any real threat to people at present.

"It's better to hit the moon than to let it hit the earth, both from the safety point of view and because if it hits the earth, we can't learn much interesting things," Gray said.

Author | Alvin Tang

southern window's international new media.