May 20 2014

What did the Sun ever do for us?

The Sun. That great big ball of fire in the sky. But what did it ever do for us? At the simplest level the Sun gives us light and warmth. As humans this is what we need to survive. It provides us with day and night as it lights up the day side of the Earth. This is in part caused by the Earth’s rotation but it is the Sun that provides the light. The light is important to us as Humans as we use it to see our way around the Earth going about our day to day lives, without it we would be in permanent darkness. But how much light does the Sun give off? It burns through a lot of material every second (see fact two) and this generates 3.9×10^26 watts of light which is quite a bit more than your average household lamp. This light is given off in all directions and only a small fraction of it reaches Earth, as the Earth is tiny in comparison to the Sun. However, we are at just the right distance from the Sun so that the light is not too blinding or full of radiation to be terminally harmful to life on Earth. Plant life uses Sun light to generate it’s own energy in a process called photosynthesis, which in turn gives us vegetation, plants, trees and grass. Plant life then releases oxygen into the atmosphere which we Humans breath and use as a source of energy to keep us alive. Without the Sun life on Earth would be significant different from what we see around us today.

The Sun’s warmth allows water to remain liquid at temperatures that are suitable for life to exist on Earth. In fact liquid water is considered to be a key requirement in the formation of early life and was the host for Cyanobacteria which floated on the waves and turned carbon dioxide into oxygen through photosynthesis. We Humans are very approximately 60% water and it is vital to our survival. We use it for all sorts of purposes besides staying alive including, cooking, cleaning, heating, cooling, growing plants and keeping aquatic pets. None of this would be possible without the Sun’s heat.

Because the Sun is so huge (see fact one) it also provides the gravitational attraction to keep us in its orbit. This is what keeps us in our position around the Sun, just far enough away not boil off the off the water and turn us into a giant ball of rock and dust, but just close enough not to freeze all the water and turn us into a giant snowball. This is called the habitable zone around the Sun and we are in just the right place to keep us alive.

If there was no Sun we would be floating in the depths of space, completely dark and life less covered in ice and snow, so the next time you look up at the Sun remember, it made you what you are today.

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