The Sun (Sol)
- Age: 4.6 Billion Years
- Type: Yellow Dwarf (G2V)
- Mass: 1,989,100,000,000,000,000, 000 billion kg (333,060 x Earth)
- Diameter: 1,392,684 km
- Circumference at Equator: 4,370,005.6 km
- Surface Temperature: 5500 °C
- The Sun accounts for 99.86% of the mass in the solar system. It has a mass of around 330,000 times that of Earth. It is three quarters hydrogen and most of its remaining mass is helium.
- Over one million Earth’s could fit inside the Sun. If you were to fill a hollow Sun with spherical Earths, somewhere around 960,000 would fit inside. However, if you squashed those Earths to ensure there was no wasted space then you could fit 1,300,000 Earths inside the Sun. The surface area of the Sun is 11,990 times that of Earth.
- One day the Sun will consume the Earth. The Sun will continue to burn for about 130 million years after it burns through all of its hydrogen, instead burning helium. During this time, it will expand to such a size that it will engulf Mercury, Venus and Earth. When it reaches this point, it will have become a red giant star.
- The energy created by the Sun’s core is nuclear fusion. This huge amount of energy is produced when four hydrogen nuclei are combined into one helium nucleus.
- The Sun is almost a perfect sphere. Considering the sheer size of the Sun, there is only a 10 km difference in its polar and equatorial diameters – this makes it the closest thing to a perfect sphere observed in nature.
- The Sun is travelling at 220 km per second. It is around 24,000-26,000 light-years from the galactic center and it takes the Sun approximately 225-250 million years to complete one orbit of the center of the Milky Way.
- The Sun will eventually be about the size of Earth. Once the Sun has completed its red giant phase, it will collapse. Its huge mass will be retained, but it will have a volume similar to that of Earth. When that happens, it will be known as a white dwarf.
- It takes eight minutes for light reach Earth from the Sun. The average distance from the Sun to the Earth is about 150 million km. Light travels at 300,000 km per second so dividing one by the other gives you 500 seconds – eight minutes and twenty seconds. This energy can reach Earth in mere minutes, but it takes millions of years to travel from the Sun’s core to its surface.
- The Sun is halfway through its life. At 4.5 billion years old, the Sun has burned off around half of its hydrogen stores and has enough left to continue burning hydrogen for another 5 billion years. Currently the Sun is a yellow dwarf star.
- The distance between Earth and Sun changes. This is because the Earth travels on a elliptical orbit path around the Sun. The distance between the two ranges from 147 to 152 million km. This distance between them is one Astronomical Unit (AU).
- The Sun rotates in the opposite direction to Earth with the Sun rotating from west to east instead of east to west like Earth.
- The Sun rotates more quickly at its equator than it does close to its poles. This is known as differential rotation.
- The Sun has a powerful magnetic field. When magnetic energy is released by the Sun during magnetic storms, solar flares occur which we see on Earth as sunspots. Sunspots are dark areas on the Sun’s surface caused by magnetic variations. The reason they appear dark is due to their temperature being much lower than surrounding areas.
- Temperatures inside the Sun can reach 15 million degrees Celsius. Energy is generated through nuclear fusion in the Sun’s core – this is when hydrogen converts to helium – and because objects generally expand, the Sun would explode like an enormous bomb if it wasn’t for its tremendous gravitational pull.
- The Sun generates solar winds. These are ejections of plasma (extremely hot charged particles) that originate in the layer of the Sun known as the corona and they can travel through the solar system at up to 450 km per second.
- The atmosphere of the Sun is composed of three layers: the photosphere, the chromosphere, and the corona.
- The Sun is classified as a yellow dwarf star. It is a main sequence star with surface temperatures between 5,000 and 5,700 degrees Celsius (9,000 and 10,300 degrees Fahrenheit).
- The Aurora Borealis and Aurora Australis are caused by the interaction of solar winds with Earth’s atmosphere.
- What type of star is the Sun? Although we think of our Sun as a unique celestial body, it is, in fact, one of trillions of stars in the universe. On top of this, the Sun is rather ordinary as far as stars go. The official classification for our Sun is G V star (often referred to as a Yellow Dwarf star), which means that it is a main sequence star whose surface temperature is between 5027°C and 5727°C. Some estimates for stars similar to the Sun in the Milky Way galaxy alone are as high as 7 billion. If this number is correct, there could be over one trillion stars that are roughly the same as our Sun in the universe.
- Does the Sun have another name? While our Sun does not have an official scientific name, it does have another common name: Sol. This name originates from the ancient Roman’s god of the Sun, Sol. This alternate name is where we get the term “solar system,” which literally means system of the Sun. © The Planets.org
2. And the Sun is mostly hydrogen and heliumIf you could take apart the Sun and pile up its different elements, you’d find that 74% of its mass comes from hydrogen. with 24% helium. The remaining 2% is includes trace amounts of iron, nickel, oxygen, and all the other elements we have in the Solar System. In other words, the Solar System is mostly made of hydrogen.
3. The Sun is pretty bright.We know of some amazingly large and bright stars, like Eta Carina and Betelgeuse. But they’re incredibly far away. Our own Sun is a relatively bright star. If you could take the 50 closest stars within 17 light-years of the Earth, the Sun would be the 4th brightest star in absolute terms. Not bad at all.
4. The Sun is huge, but tinyWith a diameter of 109 times the size the Earth, the Sun makes a really big sphere. You could fit 1.3 million Earths inside the Sun. Or you could flatten out 11,990 Earths to cover the surface of the Sun. That’s big, but there are some much bigger stars out there. For example, the biggest star that we know of would almost reach Saturn if it were placed inside the Solar System.
5. The Sun is middle agedAstronomers think that the Sun (and the planets) formed from the solar nebula about 4.59 billion years ago. The Sun is in the main sequence stage right now, slowly using up its hydrogen fuel. But at some point, in about 5 billion years from now, the Sun will enter the red giant phase, where it swells up to consume the inner planets – including Earth (probably). It will slough off its outer layers, and then shrink back down to a relatively tiny white dwarf.
6. The Sun has layersThe Sun looks like a burning ball of fire, but it actually has an internal structure. The visible surface we can see is called the photosphere, and heats up to a temperature of about 6,000 degrees Kelvin. Beneath that is the convective zone, where heat moves slowly from the inner Sun to the surface, and cooled material falls back down in columns. This region starts at 70% of the radius of the Sun. Beneath the convection zone is the radiative zone. In this zone, heat can only travel through radiation. The core of the Sun extends from the center of the Sun to a distance of 0.2 solar radii. This is where temperatures reach 13.6 million degrees Kelvin, and molecules of hydrogen are fused into helium.
7. The Sun is heating up, and will kill all life on EarthIt feels like the Sun has been around forever, unchanging, but that’s not true. The Sun is actually slowly heating up. It’s becoming 10% more luminous every billion years. In fact, within just a billion years, the heat from the Sun will be so intense that liquid water won’t exist on the surface of the Earth. Life on Earth as we know it will be gone forever. Bacteria might still live on underground, but the surface of the planet will be scorched and uninhabited. It’ll take another 7 billion years for the Sun to reach its red giant phase before it actually expands to the point that it engulfs the Earth and destroys the entire planet.
8. Different parts of the Sun rotate at different speedsUnlike the planets, the Sun is great big sphere of hydrogen gas. Because of this, different parts of the Sun rotate at different speeds. You can see how fast the surface is rotating by tracking the movement of sunspots across the surface. Regions at the equator take 25 days to complete one rotation, while features at the poles can take 36 days. And the inside of the Sun seems to take about 27 days.
9. The outer atmosphere is hotter than the surfaceThe surface of the Sun reaches temperatures of 6,000 Kelvin. But this is actually much less than the Sun’s atmosphere. Above the surface of the Sun is a region of the atmosphere called the chromosphere, where temperatures can reach 100,000 K. But that’s nothing. There’s an even more distant region called the corona, which extends to a volume even larger than the Sun itself. Temperatures in the corona can reach 1 million K.
10. There are spacecraft observing the Sun right now.The most famous spacecraft sent to observe the Sun is the Solar and Heliospheric Observatory, built by NASA and ESA, and launched in December, 1995. SOHO has been continuously observing the Sun since then, and sent back countless images. A more recent mission is NASA’s STEREO spacecraft. This was actually two spacecraft, launched in October 2006. These twin spacecraft were designed to watch the same activity on the Sun from two different vantage points, to give a 3-D perspective of the Sun’s activity, and allow astronomers to better predict space weather. © Universe Today