Sun and its Significances

Sunset over the Rocky Mountains.

The influence the Sun has had not only on evolution, but also human culture is astounding. While the importance of the Moon is not clear to many, the life giving rays of the Sun are and have been for millenia. The tremendous mass of the Sun allows for the fusion of atoms. It is this process that generates the energy to sustain life on Earth in the form of ultraviolet radiation, visible light, and infrared radiation. Neither a liquid nor solid, the Sun is composed of a number of gaseous layers. The lower density photosphere is where most visible light originates from and is often referred to as the "surface" of the Sun. The less dense, dim layer above the photosphere is called the chromosphere. This layer can only been seen with special filters or during a total solar eclipse where the photosphere is blocked. While the temperature drops between these two layers, from 5800 K to 4000 K, the temperature rises to about 10,000 K at the top of the chromosphere. Between the chromosphere and the corona, the outermost region of the Sun's atmosphere, is a section known as the transition zone. This zone is where the temperature skyrockets up to 1 million to 2 million K. The rise in temperature is due in part to the highly ionized elements found in the corona.

The Sun has received much reverence, but for a star it is quite average. In stellar classification, the Sun falls in with main-sequence stars. The Balmer-based spectral types are arranged by surface temperatures for the OBAFGKM sequence where O is the hottest and M is the coolest. Classification is then broken up further into ten temperature subdivision. These are designated by integers where 0 is hottest, and 9 is coolest. As a G2 spectral type, the Sun is grouped with the common main-sequence stars of M, K, and G. Compared to other stars, the Sun also has an average mass and a lower luminosity. Still, from the cultures of the ancient Egyptians to that of the Chinese, the ancient religions of Greece to those of modern day, the Sun remains an inspiration.

EDIT: I was recently shown this article on the Sun and the argument that it is not truly average. It's an interesting read and perspective, and as I have way fewer credentials, I don't think I rightly can disagree; however, I will say perspective is everything. This focuses on mass present day. There is little mention to the fact that giants and supergiants have very short lifespans especially compared to red dwarfs and brown dwarfs. I had been taught that we still haven't a clue as to the life cycle of brown dwarfs and red dwarfs because they have such an exceedingly long life. I'm personally curious as to how the Sun would match up compared to all the giants, supergiants, brown dwarfs, and red dwarfs that ever existed. Either way, looking at different perspectives is important, as is giving others the ability to see it!

I'm pretty sure I'll be bringing up more astronomy here in the future. While I try to keep posts a relatively nice length, there is still much left unsaid and other topics and photos left untouched.