Astronomers have long known that Pan, one of the “shepherd moons” in Saturn’s rings, had a weird shape. But it took this week’s high-resolution images from the Cassini orbiter to show them just how weird.

Cassini got its closest look ever at Pan on Tuesday, when it came within a little more than 15,000 miles of the 20-mile-wide moon. In the close-ups released on Thursday, the thing looks like a flattened flying saucer, complete with a bulging ridge around the edge.

Overnight, the views sparked rounds of hilarity and awe on Twitter. Was it a cosmic turtle shell? Walnut? Ravioli? And what’s behind that strange, strange shape?

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