Friday Night Gaze #2 - The Sun - Star Of Our Planet Earth

                                          The Sun - Star Of Our Planet Earth

Hey steemers, it´s @flurgx here and I´m delighted to bring you another astronomical quality post only to be found here on Steemit!

I decided to bring content more often then once a week because once a week seems to be too infrequently. Eventually I´ll change the name of the series to a less weekday dependent one ;)

Today I want to present you in detail the most important star in the whole universe, our sun! It dispenses light, warmth and a lot more of electromagnetic energy in an enormous amount. This is possible because it produces its energy in the center, its core, thru nuclear fusion. But let´s start at the beginning.

The sun was "born" about 5 billion years ago. 

After it formed out of a gigantic nebula, the planets began to develop. 

Today we have a satellite called SOHO (Solar and Heliospheric Observatory) in space, observing the sun 24/7 since 1996. It makes sense, if we want to understand how stars actually function, to first have a look at our sun, because it´s the closest star. SOHOs homepage has a category "the sun now" - so let´s have a closer look

SOHO has different filters which it uses to observe the sun. With this EIT 304 filter we can see several things.

First of all we see that the surface of the sun is not flat/smooth/even ... there seems to be "dots" on the surface of the sun. Astronomers call this "granulation". Indeed the surface of the sun is behaving like boiling water. Because the heat is transported in the same way, thru convection. Hot matter rises. Cold matter subsides. The surface of the sun has an average temperature of 5.800°C.  

If we look at the fringe of the sun we can see small "clouds" going up into space (at 9 o´clock). Those clouds are plasma filaments, called solar flares, which are bursting into space on a more or less regular basis, depending on the activity of the sun. We can take a more detailed look at on of these flares.

This picture was taken by  Hinode's Solar Optical Telescope  in 2007. 

Being so close at the suns surface, it´s a good point to get an idea about the size of the sun, by inserting the Earth in scale into the picture.

Indeed the sun is 110 times bigger in diameter than the Earth.

If we look at the sun thru a plain yellow/white filter, we can suddenly see black dots on the surface. We can also still se the granulation, but additionaly we can also see the so called sunspots, pointing from the center to 9 o´clock.

 

The Earth would fit in one of those spots. 

Before I said that the average temperature of the sun is around 5.800°C. Well the temperature of the sunspots is around 1.000°C cooler, that is why those areas of the sun appear darker.

Another interesting fact is that the sun is actually rotating. Differential. Which means that at the equator the sun is around 1 week faster than at its poles. You can see this at the video if you look closely. It´s 34 days at the poles, and 25.5 days at the equator. Roughly 3 1/2 weeks. 

----

Now if we start comparing the sun with other stars we quickly find out that the sun is quite a small star, Indeed it is classified as a yellow dwarf star. I do have a last picture from NASA for you, try to find the sun ;)

That´s it for today - I hope you liked my excursus. Feel free to ask any questions in the comments below. I´ll talk about other stars and their seizes in the near futue.

Follow me @flurgx and if you like to read my first entry, I´ll show you the way

https://steemit.com/astronomy/@flurgx/friday-night-gaze-1-what-to-see-on-the-nightsky-in-june-2017

Clear skies!