i  sun
Solar energy is dependent on… the sun! Who would have guessed!? As solar studs, I think it’s pretty important for all of us to have (at least) a basic understanding of the star that unequivocally is the reason there is life on earth.

First, a little history; About 4.5 billion years ago, gas and dust coalesced and formed what turned into our solar system (you know, the sun, eight planets, one newly minted dwarf planet named Pluto and other comets and asteroids). Our Sun makes up 99% of the mass in our solar system.

Despite the importance we hold for our sun, it turns out that our personal star is one of over a 100 billion in the Milky Way Galaxy and happens to be pretty average in size. This is a good thing, because stars with a higher mass burn out after a few million years (a blink of an eye when discussing the cosmos). Our sun, on the other hand, is calculated to burn for another 4,500 million years.

The way the sun functions is pretty awesome. It’s essentially a giant nuclear reactor. At its super dense core, hydrogen atoms fuse to create helium at the incredible rate of 700 tons per second. This reaction creates energy. The energy is carried from the core to the surface of the sun with photons-particles of light. It takes the photons more than a million years to migrate from the core to the surface of the sun. The photons then travel down to us at earth.

The sun is about 10,000 degrees Fahrenheit on the surface and 28 million degrees Fahrenheit at its core. Think about that the next time you complain about your summer heat!

-Nat Smith


Posted by Danny Kennedy

Danny Kennedy co-founded Sungevity and now serves as strategic advisor. He is an internationally recognized opinion leader on climate and energy issues. He is the author of Rooftop Revolution: How Solar Power Can Save Our Economy - and Planet - from Dirty Energy (2012), a book that has been described as the clean energy manifesto for the next greatest generation.