by ANNIE FURMAN
It might come as a surprise that there our Sun can be described, by astronomers, as cold. Our Sun being cold is hard to fathom, especially after the hot summer we’ve had. In fact, many people think that our Sun is the hottest object imaginable. However, when we broaden our range of objects we find that the Sun is relatively cold.
While taking a closer look at this concept we can break this into two perspectives. We can observe the relative parts of the star itself or we can compare the star to other stars outside of our solar system.
To better understand the relative temperature of the Sun, we need to look at the temperatures of each layer. The core of the Sun can be approximated at around 27 million degrees F. This extreme temperature is due to the nuclear fusion, which is the process of hydrogen atoms getting compressed and fused into helium. The next level of the Sun is called the photosphere and can be measured at 10,000 degrees F. Even though the photosphere is extremely hot, we can see how it is much cooler than the core of the Sun. The same can be said for the sunspots which are found on the photosphere. These sunspots have temperatures as low as 7,300 degrees and are considered to be the coldest part of the Sun. Each of the above definitions came from space.com.
This is where we see our concept of relative measurements present itself. If we were to simply examine the sunspots we would simply consider them to be extremely hot, but when you examine them in comparison to the core of the Sun, you can see how they can actually be described as relatively cold. On a larger scale relative measurements allow us to compare our sun with other stars outside of our solar system.
According to solarsystemquick.com, Sirius A, the brightest neighboring star in our night sky, has surface temperatures reaching to 18,000 degrees F, which is almost twice as hot as the Sun. Sirius B is almost five times the temperature of the Sun, with a surface reaching approximately 45,000 degrees F. If we were to only examine these two stars without using any Earthly objects as a comparison, it would be easy to see how our Sun is in fact cold. In late winter, you’ll be able to view Sirius in the evenings above campus.
According to universetoday.com, the hottest stars in the universe are known as blue stars. A great example of a blue star is Rigel, which is located in the constellation Orion. Rigel has 17 times the mass of the Sun and has a surface temperature of approximately 19,340 degrees F.
So it is fair to say that when we compare our Sun to other stars it really is unimaginably cold, even if this may seem unfathomable.
