If you want to know more about the Sun, you are at the right place. You probably know that the Sun is ultimately the reason why we still have life on Earth. Without the Sun, not only humans, but other living organisms cannot survive. Lying at the very center of our solar system, it is by far the most massive celestial object near our Earth. It holds almost the entire mass of the solar system (only less than 1% are accounted for planets).
Approximated Age: 4.6 billion years (The oldest star in the Milky way is around 14.46 billion years)
Distance From the Earth: 149.6 million Kilometers (1 AU)
Mass: 1.98855×1030 Kg
Stellar Type: G-type main-sequence
Diameter: 1,392,684 km
Surface Temperature: 5,772 K
15. Our Sun is One of the Smallest Stars in the Universe
The Sun is the largest celestial body in our solar system. But compared to other stars, it’s pretty small. One of the largest stars in the Milky Way galaxy, VY Canis Majoris is almost 17 times more massive than the Sun. If placed at the center of our solar system, the star would possibly engulf the orbit of the planet Jupiter.
14. Sun’s Composition
Our Sun is primarily composed of hydrogen and helium as they account for 74.9% and 23.8% of the Sun’s total mass respectively. The rest is comprised of various heavy metals and other variable gases such as carbon, neon and oxygen. Do you know that helium was first discovered while observing the Sun’s spectrum in 1868.
13. Its Dense Core
Sun’s core extends from the center from about 25% of the total solar radius. The calculated density of the Sun’s core is about 150 g/cm3. This is the only region on the Sun that produces energy or thermal energy through the process of fusion. It’s estimated that almost 99% of the solar energy is generated within 25% of the Sun’s radius, and after 30% radius, the fusion process is completely stopped.
12. It Takes just over 8 Minutes For Sunlight to Reach the Earth
Let’s do some math. The mean distance between the Earth and the Sun is around 149.6 million kilometers, which is also denoted by 1 AU. Now, we know that the speed at which light travels is around 300,000 km/s, if we divide these two numbers we get exactly 496.7 seconds or 8.2 minutes.
11. The Sun Travels At a Speed of 230 km/s
The Sun is among the billions of other stars in the Milky Way galaxy, which are continuously revolving around the galactic core. Located at a distance of 26,000 light years from the galactic nuclei, it takes the Sun and our entire solar system 250 million years to complete a single revolution at a speed of 230 km/s. This time period is also known as a galactic year.
10. Current Missions to The Sun
Solar and Heliospheric Observatory (SOHO)
Solar Dynamics Observatory, PICARD and Solar and Heliospheric Observatory (SOHO) are some of the ongoing space missions, which are currently observing the Sun and its various characteristics.
9. Future Missions to the Sun
In 2018, NASA will launch its scheduled Parker Solar Probe to study the outer corona of the Sun. The probe will approach the Sun at 5.9 million kilometers to closely study the structure and dynamics of the magnetic fields at the sources of solar wind. The Indian space agency, ISRO will also launch their Aditya-L1 spacecraft to study the Sun, most probably by 2020.
8. More Than a Million Earths Can Fit Inside the Sun
Yes that’s right. The Sun as big it is, it would take around 1.3 million Earths to entirely fill it up. You can do the math yourself, if the volume of the Sun is 1.412 x 1018 Km3 and the volume of the Earth is 1.083 x 1012 Km3 then by dividing those two we get 1,300,000. That’s our answer.
7. The Sun is Almost a Perfect Sphere
Kepler 11145123 Compared to the Sun
Sun is nearly a perfect sphere. The diameter between its poles and the diameter between the two most outward and opposite points on the equator have a difference of just 10 kilometers. But more recently, astronomers have discovered a star rounder than the Earth, and it’s known as Kepler 11145123.
6. Mythological Importance
The Sun has been in the center of most of the world religions and beliefs. In the ancient Egypt, the Sun was worshiped as the god Ra, god of light, and portrayed with a falcon head and a sun-disk with a snake on top of it. In Hindu mythology, the Sun is represented by Surya, who is equivalent to Greek Helios.
5. The Sun contains 99.86% of the mass in the Solar System
The Sun itself contains about 99.8% of the total mass of the entire solar system. About less than 1% of mass is comprised of planets of which Jupiter is the most dominant. Sun’s mass is about 330,000 times the total mass of the Earth.
4. Differential Rotation of the Sun
Differential rotation is a phenomena where different layers of a same rotating body are moving at different angular velocities. This can either be observed at different latitudes, depths of the body or both at a same time. On the Sun, the rate of surface rotation is observed to be fastest at the equator, and it decreases in the higher latitudes. The solar rotation period is around 24 Earth days at the equator and almost 38 days at the poles.
3. Sun’s Age
The estimated age of the Sun is about 4.5 billion years. It has used almost 45% of its hydrogen core and it will burn the rest of it steadily up to 6 billion years or so, after that the solar core will go through a rapid increase in density and temperature while its outer layers expand to eventually transform into a red giant. It’s been estimated that during that phase, the Sun will engulf the orbits of Mercury and Venus and make the Earth entirely inhabitable.
Sunspots are temporary phenomena occurring in no particularly order on surface of the Sun. These spots are relatively cooler and darker than the rest of the Sun’s photosphere. While the temperature in Sun’s photosphere can range from 4,500 K to 6,000 K, the sunspots have a far lesser temperature of about 3,800 K.
While they are caused by some interaction with the Sun’s magnetic field, the entire process is still under scrutiny. On an average, these sunspots are about 1,500 km wide, while they can be as huge as 120,000 km wide in some cases. Such sunspots are fairly visible from the Earth with the help of a telescope. Their numbers vary in every 11 years or so.
1. It’s Strong Magnetic Field
Earth’s Magnetic Field Interacting with interplanetary magnetic field
Sun has variable magnetic field that varies largely across its surface. Near the poles, the magnetic field is weak, around 2 Gauss, while the magnetic field strength of sunspots is as high as 4,000 Gauss. The magnetic field of the Sun also varies with time. Perhaps the most prominent time of Sun magnetic field is the solar maximum, 11 year cycle.
On a comparative scale, the Sun’s magnetic field is nearly twice as much stronger than the Earth’s. Researchers believe that this variation in the magnetic field is due to the phenomena called differential rotation, where the Sun’s core rotates far more vigorously than its visible atmosphere.