The Sun is an ordinary star but the center of everything in our solar system. Its gravity holds the planets in orbit, its light and heat make life on Earth possible, and its activity affects space all the way to the edge of the heliosphere. Gravity: the anchor The Sun contains about 99.8 percent of … Read more
A solar flare is a sudden, intense burst of radiation from the Sun’s surface, released when tangled magnetic fields near sunspots snap and reconnect. A large flare can release as much energy as billions of nuclear bombs in a few minutes. Flare classes Flares are ranked by their peak X-ray brightness, measured by satellites. Each … Read more
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
Comets and asteroids are both leftovers from the formation of the solar system about 4.6 billion years ago. The main difference is what they are made of, which determines how they behave near the Sun. Asteroids: rock and metal Comets: dirty snowballs Famous comet: Halley’s Comet returns about every 76 years and is next expected … Read more
Astronomers have not yet found a true “Earth twin”, a rocky planet of Earth’s size orbiting a Sun-like star at the right distance and with signs of life. But they have found many planets that share some of Earth’s key features, and statistics suggest that such worlds are common. What “Earth-like” means Scientists usually look … Read more
