Channel Your Inner Hermione Granger
It's true that attempting to write about something you don't know enough about or nothing at all can be challenging. So most of us steer clear of this particular subject at hand.
The unknown has always been scary, like looking into the abyss and never knowing what to expect. What's waiting once you reach the bottom?
It's a normal reaction; it's a human reaction. We're not expected to know everything about every single subject that exists (science, music, art, sports, technology, you name it). That's the beauty of it, isn't it—to be able to learn something new, to feed your thirst for knowledge, or just simple curiosity.
So it's okay not to know or understand everything. At the end of the day, we can only process so much data before we overload or steam starts coming out of our ears.
However, if you truly want to test yourself and your ability to write about a subject you're not knowledgeable about, then you can always do a little research.
Thankfully, there's Google, and Google knows it all, right? It knows you don't know what you don't know.
There are books, as archaic as that might seem when there's this wonderful thing called the Internet, but it can't hurt to check, just in case.
In conclusion, with a little effort, you can write about anything you want. It depends on whether you're interested enough to spend more time on the given subject.