Living With A Star- The Sun

We have our own star- the mighty Sun. The Sun is the biggest source of heat and light in our solar system. It is one of the several trillion stars in the Milky Way Galaxy. Though it is massive, it is classified as a yellow dwarf star. Without it, life might not exist, and that makes it very important to us. 

To ancient people, the Sun was something to worship. Various religions around the world venerated the Sun as a god with various names. 

Image result for Sun. Size: 160 x 160. Source: www.physics.upenn.edu

Solar Physics

Our sun is very special to us and the solar system. So, we have a separate branch of physics specially for our dear Sun.Solar physicists seek to explain how the sun works and how it affects the rest of the solar system They take  measurements of the temperature and have assigned it a stellar ‘type’ based on their measurements. They figure out its structure. Their studies help us to know more about the other stars.

Structure of the sun

The Sun is basically a big sphere of superheated gas. It has an outer solar atmosphere, which is called the corona (not the virus of course).  It’s an incredibly thin layer of superheated gas having over a million degrees temperature. Below that lies the chromosphere. It’s a thin, reddish-hued layer of gases and its temperature changes from 3500℃ at the base to 35000℃  where it transitions up to the corona. Next is the photosphere, where temperatures range from 4000°C to 5700℃ . When you look at the sun, the photosphere is actually what you see. The sun is actually white(believe me), but it appears yellowish because its light travels through our atmosphere, which removes blue and red wavelengths from the incoming light. After the photosphere, we have the convective zone. It contains bubbles, which are currents moving through the Sun. The next layer is the radiative zone. This region truly does radiate heat from the center of the Sun up to the convective zone. The final layer is the solar core. This is a huge nuclear furnace where nuclear fusion happens. The temperature here is 15million degrees celsius. The rest of the Sun pressing down on it provides a pressure 340 billion times the earth’s atmospheric pressure at sea level (the poor core has a lot of pressure indeed!). The Sun fuses about 620 metric tons of hydrogen to helium each second, and that’s what gives out all that heat.

Heliopause

The solar wind from the sun extends out about 100 astronomical units, and creates a bubble that surrounds the solar system. The bubble’s inner edge is called the heliopause. 

Sun spots

The surface of the sun is dotted with dark regions called sun. Look who has acne problems! Well, these are not really acne. These are areas threaded with magnetic fields and look dark because they are cooler than the surrounding regions. Sunspots appear in eleven year cycles.  As the Sun reaches solar minimum and solar maximum through the solar cycle, the spots change darkness. These sunspots are related to solar activity.

https://en.wikipedia.org/wiki/Sun
https://solarsystem.nasa.gov/solar-system/sun/in-depth/

Categories: Science

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