The next neighbor on the block we are setting out to meet can be, without a doubt, considered mayor of the celestial neighborhood: The Sun.
Just the Facts:
The Sun is by far the biggest thing in our solar system. It contains 99.8% of all of the mass in the solar system. The Sun is about 93 million miles away from the Earth, just the right distance away so that we are not too hot or too cold. However, if the sun were to suddenly stop shining, we would not know about it on Earth for about 8.3 minutes because that is how long it takes light to get here from the Sun. There are two things that are vital to keep in mind when discussing the Sun; it is MASSIVE and HOT. The radius of the sun is a bit over 430,000 miles. That is almost twice the distance between the Earth and the moon. Meanwhile, the temperature at the surface is a sweltering 10,000 degrees Fahrenheit (5800K) while at the core it is an unconceivable 28 million degrees Fahrenheit (15.6 million Kelvin).
Where did it come from?:
To understand where the Sun comes from, we need to know what is inside of it. The Sun contains about 73% Hydrogen and 25% Helium. However, there is still 2% of the Sun that is made up of heavier elements like iron, lithium, carbon, and basically any other element you can think of. The Sun creates it’s energy by taking Hydrogen atoms and fusing them into Helium atoms thus releasing energy and light. In fact, the famous equation E=mc2 is what governs energy creation in the Sun. Every second in the Sun, 700 million tons of Hydrogen atoms are converted to 695 million tons of Helium atoms. The missing mass is converted into energy through the proportionality constant the speed of light squared, c2. If the sun were big enough, it could also fuse Helium atoms together to make Lithium and so on down the periodic table, creating heavier and heavier elements. However, due to the structure of heavier atoms, Iron is the most massive element that can be produced in the center of a star. However, we know that heavier elements than Iron can be found in our solar system, Uranium for example. There is only one way that elements heavier than Iron can be created naturally; in a supernova. That’s right, our solar system was created from the remains of a supernova.
Our Sun and the rest of our solar system was created from the stuff left over from a dead star that exploded as it died. The gas and dust that was left over from the supernova slowly gathered together through gravity. As most of the material gathered in one central point, friction heated the material up. Once it got hot enough, Hydrogen was fused into Helium and our Sun was born. If this is still confusing, I will defer to Stephen Hawking and Benedict Cumberbatch to explain the origins of our solar system:
Why should I care about it?:
Well, I think we all know that we owe the existence of life to the Sun, but here are some other interesting things about the Sun that impact our lives.
Reason 1: The Sun is Dynamic (and dangerous)
The Sun looks pretty boring from the surface of the Earth; it is round and bright. However, it is so much more than a glowing ball. The surface is churning with tremendous energy, equivalent to many many nuclear warheads and all of this energy manifests itself in several ways.
On Earth, we have earthquakes, where two tectonic plates slide against one another; but on the Sun there are sunquakes, caused by the massive turbulence of superheated gas churning within the sun. The rapid movement of gas causes shockwaves that propagate through the Sun. They are so powerful that we can actually measure them using satellites because the surface of the sun is constantly shaking and moving due to them. In fact, this is exactly what NASA’s SDO project does.
In addition to sunquakes, there are events called flares, prominences, and coronal mass ejections. These three events are related to one another and are all caused by fluctuations in energy and the Sun’s magnetic field. Basically these events shoot plasma out of the sun. If the material loops back and returns to the Sun, it is called a prominence. If it extends straight out of the sun, it is called a flare. Finally, the material that is flung out of the sun through a flare is called a coronal mass ejection (CME). These CMS’s can be especially important for Earthling’s because if they are powerful enough, they could knock out any satellites in its way. For this reason, there are many satellites orbiting the sun giving a space weather forecast to try to avoid such complications.
Reason 2: The Sun is our Protector
Remember how those CME’s are caused by the Sun’s magnetic field? Well it turns out that we rely upon the magnetic field of the Sun to protect us from the harsh radiation of space. The magnetic field of the Sun is incredibly powerful and incredibly complicated. It is so powerful in fact that its influence can be felt far outside of Pluto. It creates a shell around our solar system called the heliosphere. If we were to travel outside of the heliosphere, we would be bombarded by radiation from deep space. These particles don’t normally reach Earth because they are deflected away by the Sun’s large magnetic field. On a side note, Voyager I is close to becoming the first man-made object to ever travel outside of the heliosphere.
Summing it all up:
The Sun can giveth and the Sun can taketh. On one hand, the Sun is necessary for life on Earth though the light and energy heating our planet and making photosynthesis possible. On the other hand, CME’s pose a risk to space travel and satellites. Also, in about 5 billion years or so, the Sun will begin to run low on Hydrogen fuel. When that happens, it will expand in size, engulfing and incinerating our planet. So, next time you wake up to a bright sunny day, remember that there is a lot more than meets the eye when it comes to the Sun.