That's because 10-year-old Linus Hovmöller Zou is listed as a co-author of a scientific paper in an established journal, along with his father, Stockholm University structural chemist Sven Hovmöller.
Father and son puzzled out the structure of certain kinds of crystals called approximants. These, of course, are related to quasicrystals, and if you are like me you are still completely in the dark as to just what this pint-sized Hawking and his dad have done. Briefly, crystals are molecules that interlock in regular, repeating often latticelike structures. Quasicrystals don't have the same precision regularity and so are a deeply weird part of the universe. The guy who confirmed their existence earned the 2011 Nobel Prize in chemistry. And he was a dinner guest at the Hovmöller household after winning it, so young Linus comes by his curiosity honestly.
No word on whether or not he gets extra credit for this in his own science class.