The Sun: The Life-Giving Magnet in the Sky
4.5 billion years ago, in the Orion Spur of the Milky Way galaxy, a swirling cloud of gas and dust collapsed under the weight of its own gravity. This so-called solar nebula spun faster and faster, and—as it eventually flattened out—most of that material drew toward the center, giving birth to our home star, the sun.
The sun is the source of life as we know it. Without its light, energy, and heat, we could not survive.
Now a yellow dwarf, the sun is currently halfway through its lifespan. It makes up roughly 99.8 percent of the mass of the entire solar system. Because of this mass, the sun has a strong gravitational pull on everything in the solar system. Without the sun, the planets, dwarf planets, asteroids, and comets in the solar system would just slide off into space.
At its equator, the sun rotates approximately every 27 days. But at its poles, it rotates roughly every 36 days. Sounds strange, right? Well, the sun isn’t made of solid matter like Earth is, so that means that different parts of the star rotate at different times.
Earth sits approximately 93 million miles away from the sun, which has a radius of 432,168.6 miles, according to NASA. If the sun were the same height as the average door frame, Earth would be the size of a Nickel.
What Makes Up the Sun?
The atomic weight of the sun is composed of 92.1 percent hydrogen and 7.8 percent helium, with traces of carbon and nitrogen. (By mass, it’s more like 70.6 percent hydrogen and 27.4 percent helium. It has six layers: Its core, the innermost layer, reaches temperatures of up to 27 million degrees. This is where the sun gets all of its energy. Within the core, hydrogen atoms join together in a thermonuclear reaction to create helium, according to NASA.
This energy radiates out through its layers and into the solar system as energy, radiation, and solar wind. Radiation emitted from the sun’s core bounces around in the radiative zone before eventually reaching the top of the convective zone, a bubbling layer of piping hot plasma, 170,000 years later.
Temperatures at the sun’s 300-mile-thick surface are much cooler, about 10,000 degrees Fahrenheit. The sun’s innermost surface layer, the photosphere, is the deepest layer that we can observe. The chromosphere and corona make up the sun’s solar atmosphere.