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.
Formation
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
The
Sun is orbited by eight planets, at least five dwarf planets, millions of asteroids, and up to three
trillion comets and icy bodies. But
what does the Sun orbit?
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.
Fun Facts
- 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.
Trivia
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?
1. When the Sun will blast
its dying light, it will destroy even the asteroid belt.
2. The Sun’s surface area is
around 11,990 times greater than that of Earth.
3. The distance between the
Earth and the Sun is called an Astronomical Unit – AU.
4. The Sun travels at a
speed of 136 mi / 220 km per second through space.
5. 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.
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