The Sun is a star, the only one we can see during the daytime. When we look in the night sky, we see endless dots of light, every one of them is a star just like our Sun.
Key Facts & Summary
- The Sun is located in the center of the Solar System. It is a nearly perfect sphere of hot plasma, essentially, a hot ball of glowing gases.
- It is the most important source of energy for life on Earth.
- The Sun has a diameter of around 1.39 million kilometers / 864,000 miles. This is 109 times greater than the diameter of our planet.
- The Sun’s mass consists of 73% hydrogen, 25% helium, and smaller amounts of oxygen, carbon, neon, iron, and other elements.
- The Sun is so massive that it accounts for 99.86% of the total mass of the entire Solar System.
- The Sun currently fuses around 600 million tons of hydrogen into helium every second. It is converting 4 million tons of matter into energy every second as a result.
- This energy is the source of the Sun’s light and heat. It can take between 10,000 and 170,000 years for this energy to escape from the Sun’s core.
- Every star is classified based upon their physical characteristics. Our Sun is labeled as a G-type main-sequence star or G2V.
- The Sun is approximately 4.6 billion years old.
- Many cultures from around the world associated the Sun with their most important deity or a very prominent one, and for good reason! Without the Sun, we wouldn’t exist.
- The connection and interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate, radiation belts, and aurorae.
- Though there are billions of stars in the galaxy, our Sun will always be the most special star.
- The Sun spins once every 25 days, but at its poles, it rotates once every 35 days.
- The Sun’s core is about 27 million degrees Fahrenheit / 15 million degrees Celsius.
The English word “sun” developed from Old English “sunne.” Many cultures throughout the world had solar deities in their religions and mythologies.
The ancient Sumerians associated the Sun with Utu, the god of justice and twin brother of Inanna, the Queen of Heaven, who was identified as the planet, Venus.
In ancient Egypt, the Sun was worshipped as the god Ra while in Greece, the Sun was a male deity named Helios, and for the Japanese, the Sun was a goddess named Amaterasu.
Our Sun together with the Solar System formed from a giant, rotating cloud of gas and dust called the solar nebula, around 4.5 billion years ago.
The solar nebula collapsed due to its overwhelming gravity, it spun faster and flattened to a disk. Most of the material was pulled in the center to form our Sun, which accounts for 99.8% of the mass of the entire Solar System.
Like all-stars, the Sun will eventually run out of energy and it will swell and thus engulf Mercury, Venus, and most likely even Earth. Scientists believe that the Sun is already at around halfway through its lifetime and will last for another 5 billion years before it will shrink down to become a white dwarf star.
Size and Distance
Our Sun is a relatively medium-sized type of star. It has a radius of 432,168 mi / 695,508 km and a diameter of around 1.39 million kilometers / 864,000 miles. This is 109 times greater than the diameter of our planet.
The volume of the Sun is so great that you would need 1.3 million Earth-sized planets to fill it. Not even all the planets combined could fit inside the Sun.
The Sun is 93 million mi / 150 million km away from Earth. The nearest stellar neighbor to the Solar System is the Alpha Centauri triple star system. It is at 4.24 light-years away from us.
Orbit and Rotation
Everything in the Solar System is located in the Milky Way galaxy. The Sun orbits the center of the Milky Way, bringing the planets, asteroids, comets, and other objects along with it.
Our Solar System is moving at an average speed of 450,000 mi / 720,000 km per hour. Even though we are moving fast, it still takes us 230 million years to complete one orbit around the Milky Way.
The Sun rotates as it orbits the Milky Way’s center. Since the Sun isn’t a solid body, different parts of it rotate at different rates. At the equator, the Sun spins once every 25 days, while at the poles, it rotates once on its axis every 35 days.
Structure and Surface
All stars are basically a ball of gas, and this is also true in regards to our Sun. The Sun is made out of 91% hydrogen and 8.9% helium. By mass, the Sun is about 70% hydrogen and 27% helium.
This mass is held together by gravitational interaction, and this produces immense pressure and temperatures at the core. The core is the hottest part of the Sun, with temperatures being at around 27 million degrees Fahrenheit / 15 million degrees Celsius.
The energy produced at the core powers the Sun and produces heat and light. The surface of the Sun, the part we can see, is about 10,000 degrees Fahrenheit / 5,500 degrees Celsius. It is hot enough to boil diamonds or graphite.
The surface of the Sun is called the photosphere, and it is a 300 mi / 500 km-thick region, from which most of the Sun’s radiation escapes outward. It isn’t a solid region like the surfaces of planets, but merely the outer layer of the gassy star.
We see radiation from the photosphere as sunlight when it reaches Earth, about eight minutes after it leaves the Sun.
- If the Sun disappeared, we would only notice its absence after eight-minutes, since it takes eight minutes for sunlight to reach us.
- The Sun’s visible surface sometimes has dark sunspots. These are areas of intense magnetic activity that can lead to solar explosions.
- The Sun is actually white. We see it as yellow because of the Earth’s atmosphere. Many photos present the Sun as yellow, this is because we are very familiar with this color, however, from space, the Sun’s true color is white.
- The energy created by the Sun’s core is nuclear fusion.
- The Sun is almost a perfect sphere. There is only a 10 km difference in the Sun’s polar and equatorial diameters. This makes it the closest thing to a perfect sphere ever observed in nature.
- The Sun rotates in the opposite direction to Earth, from west to east.
- The atmosphere of the Sun is composed of three layers: the photosphere, the chromosphere, and the corona.
- The Aurora Borealis and Australis are caused by the interaction of solar winds with Earth’s atmosphere. Solar winds are generated by the Sun, they are charged particles, and they occur when the Sun’s magnetic field extends into space.
- Around 1,000 Jupiter-sized planets could fit inside the Sun. Jupiter is the largest planet in the Solar System, having more than 11 times the Earth’s diameter.
The other name of the Sun
Our Sun doesn’t have an official scientific name, however, there is one other common name for it: Sol. This name originates from the ancient Roman god of the Sun, Sol. This alternate name is where we get the term “solar system”, which means the system of the Sun.
The Sun will consume Earth, and then it will become Earth-sized
When the Sun will exhaust its hydrogen supplies, it will start to burn its helium supplies. During this period, the Sun will expand and engulf Earth. At this stage, our Sun will become a red giant type of star.
After its red giant phase, the Sun will collapse. It will keep its enourmous mass with about the same volume as our planet. When this happens, the Sun will then become a white dwarf type of star.
Did you know?
- When the Sun will blast its dying light, it will destroy even the asteroid belt.
- The Sun’s surface area is around 11,990 times greater than that of Earth.
- The distance between the Earth and the Sun is called an Astronomical Unit – AU.
- The Sun travels at a speed of 136 mi / 220 km per second through space.
- The Sun is quite small in comparison to other stars. For example, UY Scuti – a red supergiant star, has a radius of around 1,700 times greater than that of our Sun.