What are the different types of cosmic rays?

Despite the name, cosmic rays are not rays of light. They are high-energy particles, mostly atomic nuclei, that travel through space at nearly the speed of light and constantly hit Earth’s atmosphere. How cosmic rays were discovered In 1912, Austrian physicist Victor Hess carried instruments up in a balloon and found that radiation increased with … Read more

How do astronomers study what planets and their atmospheres are made of?

No one has drilled into Jupiter or breathed the air of a planet around another star. Yet astronomers know a surprising amount about what planets and their atmospheres are made of, by combining several methods. Density: rock, ice or gas? If you know a planet’s mass (from the orbits of its moons, or how it … Read more