What are the stars telling us? Stars reveal the stories about the space around them, our planet, and ourselves. They come in different sizes and colors, both of which can tell us the age and temperature of the sun. Humans are very good at recognizing patterns and for millennia we have observed the positions of the sky and learned to orient ourselves with them. Stars are the forgers of elements, creating the materials needed to form other stars, planets, and even life. So, what are the secrets of the stars? Let’s get into it!
Our sun is really big. It's about 110x larger than the earth, or more specifically 864,000 miles (1,400,000 km) in diameter. But it is not even close to the biggest star in the known universe. The award for the largest star goes to a star called UY Scuti, which is a red giant and 1,500 times larger than the diameter of the sun at 1.5 billion miles (2.4 billion km). But our sun is also not the smallest star. That title goes to an easy to remember star called EBLM J0555-57Ab. This star is just about as big as the planet Neptune, with a diameter of about 37,000 miles (59,000 km). Although they are similar sizes, EBLM J0555-57Ab is still 250 times more massive than Saturn. A sun relies on its high mass to generate the conditions needed to fuse hydrogen into helium so scientists think that that star is as small as they can get.
When we are asked to draw the sun and stars as a kid our go to color is yellow. But stars can be many colors, and those colors reveal lots of information about the stars including the temperature and a little less reliably the age. Maybe a little counterintuitive to us earthlings, the blue stars are hotter and younger, and the red stars are cooler and older. Blue stars burn at around 45,000F (25000C). This is usually done early in the sun’s life and if it remains like that it burns out relatively quickly, which is why these stars are younger. Red stars on the other hand form as a star is dying and expands, making red giants. As they run out of fuel, they burn cooler and expand, which makes huge stars like UY Scuti mentioned earlier. Red stars burn around 5000F (2700C). Our sun is yellow and burns at about 10,000F (5700C). There are also orange stars (6700F, 3700C), and white stars (17,500F, 9700C), but no purple or green stars.
The sky is filled with stars. The night sky is filled with thousands of stars, and it can be difficult to spot the more well known and notable stars. For example, Polaris is a star visible in the northern hemisphere that has been used for centuries to orient and navigate, but the star itself doesn’t really stand out. If you can find the big dipper, take the distance between the two stars on the side of the pan opposite the handle, and then move five times that distance in the direction that line points in, and then you’ll find a simple star with a big significance. Polaris sits on the earth’s axis, so it remains close enough to the north to make it a reliable tool for navigation. Another notable star is Betelgeuse, which is 700x larger than our sun. This star can be found on the left side of the constellation Orion, sitting on his right shoulder. Because it is a red giant, it can be seen with an orange/red glow.
Have you ever heard people say that you are made of stardust? Because it is true. Many of the elements found in our bodies, including oxygen and carbon are forged in stars through the combination of elements in the process of fusion. Then the elements larger than iron are created during the spectacular supernova death of a star when the sun bursts open and sends the elements out into the galaxy. If the conditions are just right, such as they are for earth, these elements form together to create life. So yes, you are a star!
Stars tell stories. Whether it's about themselves, or the space around them, or even in regards to our own planet and our bodies, stars reveal information that allows us to understand what is going on around us. On the next clear night, take a look at the stars and see if you can notice the faint hues or blues or reds. Can you find Polaris to orient yourself towards the north? Stars are massive balls of gas forging the ingredients of the universe in a spectacular show of color. That is where we come from.
We Are Made of Stardust