Neil deGrasse Tyson is now a superstar astrophysicist. He’s also a black man — one who has experienced something that’s so typical for people like him: police harassment.

Tyson posted an excerpt from his 2004 book, Dark Matters, on Facebook this week, detailing some of the “dozen different encounters” with police he drew from as he spoke with fellow attendees at the National Society of Black Physicists in 1991. Here’s one example from the book:

I had been stopped by the police while transporting my home supply of physics textbooks into my newly assigned office in graduate school. They had stopped me at the entrance to the physics building where they asked accusatory questions about what I was doing. This one was complicated because a friend offered to drive me and my boxes to my office (I had not yet learned to drive). Her car was registered in her father’s name. It was 11:30 PM. Open-topped boxes of graduate math and physics textbooks filled the trunk. And we were transporting them into the building. I wonder how often that scenario shows up in police training tapes. In total, I was stopped two or three times by other security officers while entering physics buildings, but was never stopped entering the campus gym.

For defenders of police, a typical response after police kill another black man is to find a way to blame the victim: He had a criminal record, he was breaking the law, he didn’t listen to the officer, and so on. But this is a now-renowned astrophysicist carrying math and physics books to his office — and he was stopped.

As Tyson noted, he’s not alone. The other black physicists in the room had their own stories to share. “We were guilty not of DWI (Driving While Intoxicated),” Tyson wrote, “but of other violations none of us knew were on the books: DWB (Driving While Black), WWB (Walking While Black), and of course, JBB (Just Being Black).”

Tyson’s stories also show just how known these issues have been in black communities for decades. He and other black physicists shared these stories back in 1991. And by the accounts of many black men, including senators, the stories are still by and large the same. The only reason we seem to have a Black Lives Matter movement now and not back then really seems to come down to video verifying the stories black people have been sharing for so long.

It’s often said that change comes slowly in America. But a selective higher burden of proof seems to make that true more for some groups than others.

Watch: Why recording the police is so important