Our Sun is a 4.5 billion-year-old yellow dwarf star – a hot glowing ball of hydrogen and helium – at the center of our solar system. It’s about 93 million miles (150 million kilometers) from Earth and it’s our solar system’s only star. Without the Sun’s energy, life as we know it could not exist on our home planet.
10 things
The Sun is about 100 times wider than Earth and about 10 times wider than Jupiter, the biggest planet.
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.
Measuring a “day” on the Sun is complicated. 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.
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.
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.
The Sun doesn’t have moons, but it’s orbited by eight planets, at least five dwarf planets, tens of thousands of asteroids, and perhaps three trillion comets and icy bodies.
Several spacecraft are currently investigating the Sun including Parker Solar Probe, STEREO, Solar Orbiter, SOHO, Solar Dynamics Observatory, Hinode, IRIS, and Wind.
The Sun would have been surrounded by a disk of gas and dust early in its history when the solar system was first forming 4.6 billion years ago. Some of that dust is still around today, in several dust rings that circle the Sun. They trace the orbits of planets, whose gravity tugs dust into place around the Sun.
Nothing could live on the Sun, but its energy is vital for most life on Earth.
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.
