The sun isn’t just comforting, cheerful, and a good excuse to wear shorts. Without it, there would be no life on Earth, so it’s always a good idea to appreciate our home star.
If you’re looking to get to know the sun better, here’s a list of facts that will help!
Key Highlights
- Mass: 1.9891 × 1030 kilograms
- Diameter: 865,370 mi or 1.4 million kilometers
- Temperature of the surface: 10,000 degrees Fahrenheit (5,600 degrees Celsius)
- Composition: 91% hydrogen and 8.9% helium
- Age: 4.6 billion years
- Lifespan: 9-10 billion years
- Distance from Earth: 93 million miles (150 million kilometers)
1. How was the sun formed?
Like most stars, this gigantic ball of heat and light originated in a nebula. This is a huge cloud made of dust and gas suspended in space.
Sometimes these nebulae form as a result of supernova explosions, where otherwise cold gas and dust accrete on their own.
Most likely, our solar system formed when a nearby supernova explosion kicked off a collapse of this nebula, causing the sun to form at the center with a thin disk around it.
That disk (which represented less than 1 percent of the remaining mass of the nebula) then formed into separate spheres, which became our planets.
Any remaining dust and gas got blown away by the solar wind while the sun was still young.
2. What is the sun made of?
The exact composition of the sun varies by source. It depends also on how you’re measuring the composition: by mass or by the number of atoms.
By atoms, the sun is 91% hydrogen and 8.9% helium. A further .1% of the sun is composed of trace elements, including iron, neon, sulfur, magnesium, silicon, carbon, nitrogen, and oxygen.
By mass, it is about 70.6^ hydrogen and 27.4% helium, helium being about twice as heavy as hydrogen to account for the difference between atomic number and weight.
3. Does the sun have different layers like the planets do?
It is composed of layers just like a planet. The Earth, for instance, has a solid inner core, a molten outer core, a mantle, and a crust.
The sun is similar, with an internal structure of its own. The surface – which we see when we take pictures of the sun – is called the photosphere.
Beneath that is an area known as the convection zone, so named because it transfers heat from within the sun to its surface. That material then cools and falls back toward the center of the sun.
Beneath the convection zone, we have the radiative zone, where heat travels by radiation rather than convection. And within that is the core, where fusion happens as hydrogen is transformed into helium.
4. Who “discovered” the sun?
Humankind has known about the sun since the dawn of time. Many ancient cultures worshipped it, such as the Egyptians and Mesoamericans.
Today, modern pagans and some other cultures still make the sun a central part of their practice.
If we want to name who “discovered” the sun, then that honor probably goes to Giordano Bruno. He posited in 1584 that the sun was probably just another star like the many that existed in the heavens, though he was burned at the stake for saying so.
If we want to go even further back, the Greek philosopher Anaxagoras posited that the sun was just a hot rock and the moon a cold rock that glowed as a result of reflection.
He too was sentenced to death for the proposition but escaped into exile instead.
5. How hot is the sun?
The temperature of the sun depends on which zone you’re talking about.
The surface temperature is around 10,000 degrees Fahrenheit (5,600 degrees Celsius), while the temperature at the bottom of the convection zone is about 360,000 degrees Fahrenheit (200,000 degrees Celsius).
Remember, the temperature at top of the convection zone is roughly the same as at the surface.
The radiative zone ranges from 4 million degrees Fahrenheit (2 million degrees Celsius) at the top to 12 million degrees Fahrenheit (7 million degrees Celsius) at the bottom.
The temperature of the core is, on average, 27 million degrees Fahrenheit (15 million degrees Celsius).
The sun sits at about 93 million miles from Earth (149 million kilometers). It takes light about 8 1/3 minutes to travel from the sun to Earth.
This distance is referred to as 1 astronomical unit, or AU. By comparison, Jupiter is 5.2 AU and Neptune is 30 AU.
7. How long will the sun live?
The sun has lived approximately half its life: about 4.6 billion years so far. It will live another 4-5 billion years, during which time it will become so hot and large that it will eventually engulf the Earth in its red giant phase.
However, it will get hot enough to scorch all life on Earth’s surface into oblivion in only about a billion years, at which time liquid water will no longer exist on its surface.
8. How fast is the sun traveling?
While the sun doesn’t appear to be moving from our point of view, it is actually traveling through space at a good clip.
Just as the planets orbit our sun, the sun rotates the center of the Milky Way at a speed of around 450,000 miles (720,000 kilometers) per hour.
The reason we don’t feel this incredible speed is the same reason we don’t feel our Earth rotating: we are moving at exactly the same speed, so the relative motion is null.
That results in the appearance of a stable, unchanging environment.
9. How long does it take for the sun to orbit the center of the galaxy?
The Milky Way is, to use the technical term, ginormous. It is about 100,000 light years across, which means it takes 100,000 years for light to travel from one end of it to another.
As you might imagine, that’s a big area around which to rotate. It takes the sun approximately 230 million years to make a complete orbit, which means it has done so about 20 times since it was formed.
10. How long does the sun take to rotate?
It takes an average of about 27 Earth days to rotate on its axis. Why an average? Because the sun rotates faster at its equator than at its poles – about 25 days and 36 days, respectively.
11. How many planets does the sun have?
The sun has eight planets: Mercury, Venus, Mars, Earth, Jupiter, Saturn, Uranus, and Neptune.
Pluto was demoted from planet to dwarf planet in 2006, when the International Astronomical Union made the call based on its inability to clear other objects from its orbital path.
12. What other objects orbit our sun?
Pluto is not the only dwarf planet. There are four others: Eris, Haumea, Makemake, and Ceres.
Each of these is smaller than our moon and all meet the criteria for a dwarf planet – they orbit the sun (rather than a planet, and so are not moons), they have enough mass to collapse on themselves and become nearly round – and they cannot clear their orbital paths.
Other celestial bodies circling our sun include asteroids, comets, and meteoroids. The moons of the solar system, of which there are hundreds, also orbit the sun, albeit in a tiny whirligig pattern since they are also orbiting their home planets.
13. How does the sun compare to other stars?
Want an idea of how large it is? Well, the sun is roughly 10 times the size of Jupiter!
At 864,400 miles (1,391,000 kilometers), it is 109 times the diameter of Earth and 333,000 times its mass. It is roughly 10 times the diameter of Jupiter and 1,050 times its mass.
As such, you might assume that the sun is an impressively sized body in our universe, but that’s not actually the case.
In fact, as far as suns go, it’s quite average. Scientists have located stars that are hundreds of times bigger than the sun.
For instance, the red giant Betelgeuse is 700 times the size of the sun and 15 times its mass, while Rigel is a blue giant that is 79 times its diameter and 21 times more massive.
The biggest star that we know of in the universe is called UY Scuti, a hypergiant that is 1,700 larger than the radius of the sun, into whose volume we could fit 5 billion of our suns.
14. How do we take pictures of the sun?
Turns out, traditional cameras are blinded by the sun, just like the human eye. Therefore, photos that use traditional capturing methods in the visible light spectrum just produce blobs.
For that reason, space agencies like NASA take pictures using both ultraviolet and infrared light.
The yellows and oranges we see in closeup pictures are added after the photo is taken to make it more appealing to us humans.
However, did you know that everyday people can photograph the sun using solar filters and large lenses? The best time to get a good snap is early in the morning, when the atmosphere is cool and calm.