Before we talk about other stars, though, let's talk about our own star -- the Sun!! This way, we have something to compare to. (And we can appreciate how ~boring~ the Sun really is) https://twitter.com/NASASun/status/1350168575546454018

The Sun is our closest star and is around 4.5 billion years old (4,500,000,000 years) and we know this from dating rocks in the Solar System. We've been observing the Sun with NASA's Solar Dynamics Observatory (SDO) in great detail since ~ 2010

By observing the Sun in different wavelengths, like in those cool new stamps, we can learn about different events happening on the Sun.

What I want to focus on are SUNSPOTS

Sunspots are dark regions regions on the surface of the Sun that are regions of high magnetic activity. Here are some spots!!

You can sometimes even see them with amateur telescopes (with the appropriate solar filter of course!!! You should never look at the Sun directly )

Another cool thing about sunspots is that... You can see them from even farther away. Like if you were an alien with a super large telescope monitoring the Sun for a few days, you would get data that looks like this --

That squiggly line is the change in the Sun's brightness over time and it's caused by the appearance/disappearance of spots on each hemisphere of the Sun

When the Sun gets dimmer, there are spots in our alien's telescope. And when the Sun gets brighter again, there are no spots!

Sunspots range from 10 - 100,000 miles in diameter (the Earth is a mere 9,000 miles by comparison)

Here's a cool zoom in comparison! The spots look like islands on the surface the Sun. But they're definitely not a good vacation spot (heh) as they're still 6740°F / 3727°C

Now that we know a bit about sunspots, what do spots look like on other stars?

My research focuses on young stars that are 500,000,000 years old and younger. Thanks to @NASA_TESS we can now monitor thousands of young stars to see what their spots look like!