A closer look
In 1912, Victor Hess looked at the radiation mysteriously frying his electrometers and decided the only logical next step was to ride a hot air balloon three miles into the freezing atmosphere during a solar eclipse. People thought radiation came from rocks in the ground, meaning it should decrease as you go higher. Instead, Hess discovered the radiation levels went up the higher he flew. He essentially survived hypoxia and sub-zero temperatures just to prove that the Earth is constantly being bombarded by invisible, high-energy cosmic rays shot out of exploding stars and black holes millions of light-years away.
