A physicist became a viral troll by saying a slice of sausage was a star. He later apologized.

The most effective way to warn people not to spread viral hoaxes on social media is to say, “Don’t spread viral hoaxes on social media.” Probably the least effective way is to post a hoax that goes viral, and then later explain that you were trying to warn people about hoaxes.

On July 31, Étienne Klein, a physicist at École Centrale Paris, and a researcher who has performed experiments using CERN’s Large Hadron Collider, posted a photo of a sliced chorizo sausage on Twitter and said it was a photo of our nearest neighboring star, Proxima Centauri taken by the James Webb Space Telescope. “This level of detail…A new world is revealed day after day,” he wrote in his tweet’s text (originally in French).

His post was retweeted 4,846 times as of this writing probably because yes, it looks like a plausible Proxima Centauri photo to the almost eight billion people in the world who are not trained physicists, and probably some of the ones who are. 4,846 retweets isn’t exactly “breaking the internet,” to be sure, but most of the physicist’s tweets get closer to 30.

Klein had apparently recycled a picture posted on the photo-sharing site Imgur in 2018, with a similar, though ungrammatical, joke attached. “Blood Moon as it can seen now in Spain,” wrote Imgur user superl0pez.

After Klein’s version of the chorizo joke went up, confusion reigned for a while, according to the French news site Le Point, as some users pointed out that the sausage was a sausage, and others just shared what looked like a cool picture of a star.

Then on August 2, Huffington Post France reached out to Klein for an explanation and he told them (originally in French) that it was the first time he’d cracked such a joke, and that he was “more on this network as a figure of scientific authority,” and guessed that if he “hadn’t said it was a photo [from] James Webb, it wouldn’t have been so successful.”

The next day, Klein apologized on Twitter, though he maintains that he “simply wanted to urge caution” about sharing such images online.

So remember folks: only spread photos like this if they come from qualified scientists who aren’t known for posting jokes online. Or, I guess to be on the safe side, just don’t use social media.