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(CNN) —  

Elon Musk, CEO of SpaceX and Tesla, tweeted that a “big rock” is going to hit Earth, and that we “currently have no defense.”

But NASA, seems to disagree.

Musk’s tweet was a response to another by comedian and podcaster Joe Rogan, who shared an article reporting that NASA has begun preparations for the 1,100-foot-wide asteroid Apophis, which is scheduled to pass by Earth on April 13, 2029. Apophis named after an Egyptian god of death.

Uh. What?

Musk isn’t wrong when he tweeted “Wouldn’t worry about this particular one,” though. Apophis is going to miss us by 19,000 miles. It’s rare that such a large object will be this close, so NASA scientists will take the opportunity to observe surface details and other things that may help with planetary defense.

It’s the next part of Musk’s tweet that has left people scratching their heads.

Musk didn’t elaborate on what he meant by “big rock,” so it’s hard to know what he was actually referring to.

NASA’s website, though, clearly says, “No known asteroid poses a significant risk of impact with Earth over the next 100 years.”

Lindley Johnson, of NASA’s Planetary Defense Coordination Office, reiterated that stance in a statement.

“While no known asteroid larger than 140 meters in size has a significant chance of hitting Earth for the next 100 years, NASA and its partners are studying several different methodologies for deflecting a hazardous asteroid,” he said.

Basically, even if an asteroid were hurtling toward Earth, scientists believe they will have the technology to deflect it off course and prevent collision.

NASA also has a designated department that finds undetected asteroids and tracks their orbits, so they have data on where exactly an asteroid will be up to hundreds of years in the future. Even if an undetected asteroid slipped through, Johnson said in a previous interview with CNN, that impact is extremely rare – occurring only once every two or three centuries.