SparkFun Spooktacular

Happy Halloween! In honor of today's holiday, we thought we'd do a roundup of a few spooky (or just downright strange) things in science, math and technology. From freaky weather to mysterious numbers, hold on to your hats because it's about to get weird.

1. Ball Lightning

Ball lightning is a natural phenomenon that has people scratching their heads. It usually shows up during thunderstorms as these glowing, spherical orbs that can range from the size of a baseball to something much larger. They seem to float or dart around in the air, often appearing right after a lightning strike. While many people have claimed to see them, scientists are still trying to figure out what exactly causes them.

Unlike regular lightning, which we can explain pretty well, ball lightning seems to defy our understanding of physics. It’s tough to study because it doesn’t appear on command and can't be replicated in the lab. This has led to a bunch of wild theories about what it could be — everything from burning gas, strange plasma formations, or even ghosts! The fact that it pops up randomly during intense weather and often leaves no trace behind keeps folks guessing and fascinated, making ball lightning one of nature’s coolest enigmas.

2. Belphegor's Prime

Prime numbers - there's a ton of em! 1, 2, 3... 37; the list goes on! However, there's a very big prime number that contains a lot of superstitious elements, which makes some people pretty suspicious of it. Belphegor's Prime (named for one of the princes of Hell, cool) is as follows:

Belphegor's Prime is a palindromic prime number, which means its digits are the same forwards and backwards. Around the 666 in the middle, there are 13 zeroes on each side. Anyone who's superstitious should be able to steer clear of this number, but don't think you're in danger of summoning a demon or anything by typing it into your TI-89, I think you'll be okay.

3. What is Infinity, Really?

You've heard of infinity, I'm sure. You start slapping it everywhere once you get to calculus, you saw the symbol everywhere if you went anywhere near a Forever 21 in 2012, but have you ever sat and ruminated on it? Turns out, there's many different kinds of infinity, maybe even an... infinite amount? The two main categories are countable and uncountable infinities, and I'm sure you can guess what sets them apart.

Countable infinity refers to sets that can be matched one-to-one with the natural numbers (1, 2, 3, ...). Think of the set of integers or even the set of rational numbers (like fractions). Even though these sets are infinite, we can still imagine counting their elements in a systematic way. For instance, we can list the integers as 0, 1, -1, 2, -2, and so on. This idea of being able to “count” the elements, even in an infinite set, is pretty intuitive, but it quickly becomes mind-bending when you realize that not all infinities behave this way...

Then we have uncountable infinity, which introduces a whole new level of complexity. The most famous example is the set of real numbers, which includes not just the rational numbers but also irrational ones like √2 and 𝜋. The mathematician Georg Cantor showed that the real numbers are uncountable through his diagonal argument, which illustrates that no matter which way, or how hard you try to list all the real numbers, there will always be some you miss (bummer). This revelation challenges our understanding of what it means for something to be infinite and highlights that some infinities are simply "larger" than others.

4. The WOW! Signal

The Wow! signal (named for the written explanation on the signal's printed readout) is one of the most well known stories that has emerged in the search for extraterrestrial life. Detected in 1977 by astronomer Jerry R. Ehman while working on the SETI project, this strong radio signal came from the direction of the constellation Sagittarius and lasted for about 72 seconds. What made it particularly fascinating was its unique characteristics — it had a frequency of 1420 MHz, which is the same frequency emitted by hydrogen, the most abundant element in the universe.

Prior to this, some scientists had theorized that technologically advanced extraterrestrial civilizations may try to communicate using this known frequency. This led some to speculate that it might be an alien signal, sparking excitement and curiosity among scientists and enthusiasts alike. However, all that excitement never really led anywhere.

What keeps the Wow! signal shrouded in mystery is that, despite numerous attempts to detect it again, the signal has never been repeated. This unpredictability raises questions about its origin, leading to a variety of theories ranging from natural phenomena to extraterrestrial communications, to a mass ejection of energy from a hydrogen cloud disturbed by a super-magnetic star. Who's to say!

5. Space (All of It Really, But Mostly Dark Energy)

There's a lot of spooky things on Earth, but zoom out a bit and you've got no shortage of unsettling observations and unsolved mysteries. There are the black holes, a place where gravity is so strong not even light can escape its pull. We've also got rogue planets, planets that don't orbit a star just hurtling through empty space. There are mysterious interstellar objects that show up with no explanation, like 'Oumuamua. Perhaps the most mysterious thing out there, though (aside from just the baseline creepiness of the endless, expanding void of space) is dark energy.

The universe is expanding at an accelerating rate, driven by... we don't quite know. This means that everything in the universe is getting farther away from everything else, and in the very distant future we won't be able to see anything except our own galaxy, all thanks to this force that's propelling spacetime outwards.

That mysterious force is referred to as dark energy, even though no one has seen or measured it. There are a lot of theories about what could cause this, like the energy of empty space itself being a cause for cosmic acceleration, or that something is just wrong abut the way we understand gravity. Who's to say! All in all, very spooky indeed...

What's your spookiest science interest? Let us know in the comments or on socials, and enjoy the holiday!