Summer Internships in Physics for High School Students?

NASA has several programs, and I know at least one of them is open to high school students. Check their website again. Most physics and astronomy internships are for undergraduate or graduate students. You can check and see if CERN has any high school positions, but I doubt it. And you certainly won't find any for theoretical physics until you've had a couple years of college physics. Sorry - good luck googling it. Try asking your physics teacher if they know of any - sometimes they get fliers.