This week, John Oliver's show was all about how some corrupt guardians are making money from America's ageing population.

The topic didn't have much to do with space science at all, but that didn't stop Neil deGrasse Tyson from showing up and being his usual pedantic self.

The joke started with Oliver explaining that one particularly corrupt guardian was charging the seniors under her watch over a hundred hours a day.

"Yeah, a hundred hours a day is not physically possible unless she was working on the planet Mercury where – as we all know – each day lasts 1407 Earth hours," Oliver said.

"I'll be honest that's a joke exclusively designed for Neil deGrasse Tyson, so I do hope you enjoyed it, Dr Tyson."

The camera then flipped to a video of Tyson explaining why he didn't appreciate the joke… at all.

"Yeah, but the time you gave was the rotation rate of Mercury. That's not the same thing as a day," Tyson explained to Oliver in the most ungrateful terms.

"A day on Mercury would be from sunrise to sunrise, of course, and, on Mercury, that lasts three times longer than what you just gave."

Oliver's reaction to the correction was just perfect.

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