THE SOLAR SYSTEM

The Sun is a yellow dwarf star, a hot ball of glowing gases at the heart of our solar system. Its gravity holds everything from the biggest planets to tiny debris in its orbit. The Sun is a huge ball of hydrogen and helium held together by its own gravity. The Sun is the largest object in our solar system. The Sun’s volume would need 1.3 million Earths to fill it. Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in orbit around it. The hottest part of the Sun is its core, where temperatures top 27 million degrees Fahrenheit (15 million degrees Celsius). The Sun’s activity, from its powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system.NASA and other international space agencies monitor the Sun 24/7 with a fleet of spacecraft, studying everything from its atmosphere to its surface, and even peering inside the Sun using special instruments. Sun-exploring spacecraft include Parker Solar Probe, Solar Orbiter, SOHO, ACE, IRIS, WIND, Hinode, Solar Dynamics Observatory, and STEREO. The temperature in the Sun's core is about 27 million degrees Fahrenheit (15 million degrees Celsius) – hot enough to sustain nuclear fusion. This creates outward pressure that supports the star's gigantic mass, keeping it from collapsing. 10 Need-to-Know Things About the Sun BIGGEST The Sun is about 100 times wider than Earth and about 10 times wider than Jupiter, the biggest planet. If the Sun were as tall as a typical front door, Earth would be about the size of a nickel. STAR ATTRACTION The Sun is the only star in our solar system. It is the center of our solar system, and its gravity holds the solar system together. Everything in our solar system revolves around it – the planets, asteroids, comets, and tiny bits of space debris. SUN DAY Measuring a “day” on the Sun is complicated because of the way it rotates. It doesn't spin as a single, solid ball. This is because the Sun’s surface isn't solid like Earth's. Instead, the Sun is made of super-hot, electrically charged gas called plasma. This plasma rotates at different speeds on different parts of the Sun. At its equator, the Sun completes one rotation in 25 Earth days. At its poles, the Sun rotates once on its axis every 36 Earth days. WALKING ON SUNSHINE The part of the Sun we see from Earth – the part we call the surface – is the photosphere. The Sun doesn’t actually have a solid surface because it’s a ball of plasma. DYNAMIC ATMOSPHERE Above the Sun’s surface are its thin chromosphere and the huge corona (crown). This is where we see features such as solar prominences, flares, and coronal mass ejections. The latter two are giant explosions of energy and particles that can reach Earth. Pop Culture The Sun has inspired us since ancient times. It’s central to mythology and religion in cultures around the world, including the ancient Egyptians, the Aztecs of Mexico, Native American tribes of North and South America, the Chinese, and many others.Countless musicians have written songs about the Sun. The Beatles had a hit in 1969 with “Here Comes the Sun.” Other popular songs that reference the Sun include: “Walkin’ on the Sun” by Smashmouth; “Ain’t No Sunshine” by Bill Withers; “Walking on Sunshine” by Katrina and the Waves; “Pocketful of Sunshine” by Natasha Bedingfield; and “Let the Sunshine In” by the Fifth Dimension. If you're Superman or a fellow Kryptonian, your powers are heightened by the yellow glow of our Sun, and you can even dispose of dangerous materials, as Superman and Superboy did, by hurling them into the Sun. In the 1990 science fiction film “Solar Crisis,” a huge solar flare is about to scorch Earth. Astronauts are supposed to use a bomb to divert the flare. In the 2007 film “Sunshine,” the Sun is dying, plummeting Earth into a deep freeze. To save humanity, astronauts try to reignite the Sun with a bomb, though things don't quite go as planned. In the 2019 film “The Wandering Earth,” once again the Sun is dying, but there’s no bomb this time. Instead, people build giant rocket thrusters to move the Earth to a new star system. (Like all stars, the Sun will eventually run out of energy – but scientists don’t expect this to happen for another 5 billion years or so.)