The Sun, Explained

Today, the main focus in my class was the sun. It plays a very important part in our solar system, quite intriguing isn't it?

You might already know that the sun is a star and that our earth orbits it. You might also already know that the sun is the closest star to our planet. The sun is also ALWAYS changing... do you know how scientists today track this change?

“The sun, with all those planets reloving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.” - Galileo Galilei

Lets dive into some of the key topics when learning about the sun...

Really, how big is the sun?

The sun is honestly... just as big as your average star. But don't take this as an understatment because the average star is HUGE compared to earth. The sun has a radius of 696,340 km to be exact. To put that in perspective... earth's radius is 6371 km.

Now that's just the radius, if we're talking mass... it holds 99.8% of the solar system's mass. Roughly 1.3 million earths could fit inside of the sun, I'd say that's pretty impressive.

The size of the sun is extremely important because it directly relates to fusion. In a hypothetical situation... as if for some reason the sun shrank to a size smaller than the Earth, the shrunken sun would not have enough mass to create fusion. Thus, it would burn out completely.

So, what is fusion? And why is it so important?

Fusion occurs in The Core of the sun (first layer) and results in the production of light. This light is created when two lone hydrogen nuclei (protons) fuse together, through a series of steps, and create helium. When this helium is created, a gamma ray is also released... this gamma ray is our photon (light). This photon however, must travel far and wide throughout the sun's layers before finally reaching our eyes.

With the second layer being The Radiative Zone, our photon encounters obstacles. These obstacles being multiple densly packed protons... so many that our photon cannot travel a cenimeter or two without hitting one. With every hit, it loses some of it's energy and gets lost in another direction. This zone can take thousands to millions of years for a photon to escape, making the light we witness daily ancient!

The next zone is known as The Convection Zone. Here, gases are cool enough that convection can happen. The gas here absorbs energy from the gamma rays, the energy heats it and it rises, dumping the energy (photons) off into the next layer.

Our photon then passes through the sun's atmosphere. First through the thin Photosphere, then the thicker Chromosphere. Once our photon starts to make its way through The Corona, the outermost layer of the sun's atomosphere, the temperatures start to rise. The photons pass through unimpeded and join with trillions of others, all in different directions, with some of course, heading towards earth.

It takes about 8 minutes and 20 seconds for these photons to reach earth at a distance of roughly 150 million km away. It dodges space debris and other obstacles then finally enters our atomosphere, making contact with our eyes.

The journey of light from the sun to earth may only take 8 minutes and 20 seconds, but in reality, the light we're seeing is 100's of thousands years old, and it's all thanks to fusion.

Before, I mentioned the sun is constantly changing... and that scientists can track that change. I guess we can get into that now, huh?

How is the sun changing? How can scientists track this?

Galileo was one of the first scientists to instensly track changes within the sun. After his own invention of the telescope in 1609, he soon realized something. When looking into the sky, he observed dark spots across the sun. Through these observations he confirmed that the sun rotated monthly, as the positions of the spots moved.

Fast-forward to present day, these dark spots are actually referred to as sunspots. These sunspots are directly caused by the sun's 11 year cycle, which was discovered by observing the patterns of the sunspots.

This 11 year cycle is the process in which the sun's magnetic field completely flips, which means the north and south poles of the sun swap.

The beginning of this cycle is known as a Solar Minimum, or when the sun has the least amount of sunspots. Overtime, Solar Activity increases, and so do the sunspots! The middle of the cycle is known as the Solar Maximum, or when the sun has the most sunspots... As the cycle approachs the end, it fades back into a solar minimum and a new cycle begins.

Do these sunspots have any negative effects in regards to Earth?

Solar flares usually occur near sunspots... so if there are more active sunspots, there is likely to be more solar flares. This creates an increase in the geometric storm activity for Earth. During events like sunspot maximums, we will see an increase in Northern and Southern Lights as well as possible disruptions in power grids and radio transmissions.

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I hope you enjoyed reading my post on this particular topic... stay tuned for more!