In this day and age, it may feel like humans know practically everything there is to know. Yet there are still some facts of life that have had even the smartest minds stumped for centuries: even seemingly simple things such as why we yawn, cry, or laugh. While we experience these phenomena every single day, just why we experience them is a much more complicated — and mysterious — question to answer.
1. A laughing matter
Laughter is such a major part of our lives that most of us probably haven’t stopped much to think about why we do it. Luckily, various boffins have given it more thought than we have! But even they have struggled to find a widely accepted explanation for why we laugh and react to humor and comedy in the way that we do.
What’s clear for scientists is that laughing helps unite humans. Think of all the people at a stand-up comedy show, laughing in unison at the comedian’s jokes, and you get a sense of that. But from an evolutionary standpoint, scientists have suggested that humor comes from something outside a social or physical norm for a human, but not one that is threatening and triggers a fear response. Rather, a lighthearted response helps us to foster bonds with others.
2. An age-old question
Why is it that we age, and can’t just stay young forever? This is something you might have pondered in frustration at seeing a gray hair emerge, or a wrinkle get deeper. Scientists have been on this question for a long time, and there’s big money in the anti-ageing, beauty product industry too. But though they have some knowledge of the process, they haven’t fully figured it out, it’s fair to say.
One substance scientists have pinpointed as being key to aging is free radicals: damaging reactive chemicals that attack the skin’s outer layers. But there are many other factors, and free-radical damage can be limited with protective moisturizers and a healthy diet, for example. Another factor is the shortening of protective caps of DNA known as telomeres on each chromosome in the human body. But still many questions remain. We hope they hurry up and figure it all out so we can go back to being young again!
3. Questions around gravity
You know what gravity is, right? It’s the force by which a planet like Earth draws objects toward its center. It ensures all of the planets orbit around the Sun. It’s the reason an apple falls off a tree onto the ground, as Sir Isaac Newton figured out. But scientists don’t know everything about this complex force.
One of the chief questions about gravity that scientists still have, is why does mass create gravity? Another they are not sure of is how exactly one particular object gravitationally influences another one. Yet another mystery is how weak gravity is when compared to numerous other forces of nature. C’mon scientific community, figure it all out, please!
4. Making purr-fect sense
Hearing your cat purr can be a heartwarming experience, but why do our beloved feline pets produce the endearing, low, rumbling sound? Scientists are not entirely sure of this, or why some species of cats do it and others don’t. For instance, fearsome big cats, such as lions and tigers do not purr, and the latter of those two chuffs instead. But boffins looking into this phenomenon do have a few theories as to why.
One theory is that purring is a soothing mechanism for cats, or a way to express contentment, in the same way a tiger’s chuffs seem to be. But cats also purr when scared or angry, so there’s some doubt on this. Interestingly there has also been an indication from relevant research that cats purr in order to stimulate bone growth, with the frequency at which they do it encouraging tissue regeneration.