Scientists are unable to tell us the what, why and how of some mind-blowing things. Most of the time we expect scientists, physicists and mathematicians to know the answers, but really we don’t have a clue about some really basic things in the world around us. Some of the answers may have been found by ancient civilisations … and then lost again. Doh! Some answers may be staring us in the face, but we’re not looking in the right places and some mysteries may never be solved.

Prepare to have your mind well and truly blown by some of the simple things scientists can’t explain on our list. Some of the mysteries we’ve uncovered tax the world’s greatest minds while they strive for answers, others seem so familiar that it’s unbelievable that we don’t fully understand them yet. Read our list and arm yourself with some serious mysteries to impress your mates with. From the frankly confusing act of reproduction to the complexities of the humble tomato, scientists have got their work cut out with this collection of unresolved puzzles.

15. Scientists can’t explain why aliens haven’t come to visit us yet

Seriously, we have an awesome planet, a (mostly) welcoming society and we’ve got some epic Netflix shows, so why exactly haven’t aliens come to Earth for a vacay? Is it our propensity to kill and dissect anything that’s vaguely interesting, because, you know … science? Or is it that we’re not anywhere near as interesting as we think we are? Science and math say aliens really should have turned up by now. Fermi’s paradox lays out why, and it is fairly complex, guys. Basically it boils down to the fact that with billions of ancient stars in our galaxy that are older than earth, there SHOULD be intelligent life out there. What’s more, because they’ve been around a lot longer than us, they really should have dropped by already.

14. Scientists can’t figure out why cocaine has been found in ancient mummies

Finding weird things stuffed into ancient Egyptian mummies isn’t that unusual. And researchers mostly agree that the items were buried as gifts for the gods, treasures for the dead to take into the afterlife or just part of a religious ceremony. What scientists can’t explain is how a bunch of American drugs – such as cocaine, wound up in a mummy that died long before it’s thought American settlers reached these parts of the world. The findings were so shocking that, rather than believe the scientists that found the drugs, most accused them of contamination. Which means many esteemed professors would all rather accuse fellow scientists of hoovering up blow on the regular in their labs, than believe our ancient ancestors could sail to Africa. Nice!

13. Reproduction is still a mystery to scientists

*Insert predictable joke here about geeky, nerd types never being able to understand relationships.* That stereotype aside, scientists really can’t explain why we, and other animals and creatures, get down to the nasty to populate our species. In terms of biology and efficiency it just doesn’t make sense. Described as an evolutionary anomaly, biologists say that having the male half of the population using up valuable resources without being able to produce offspring leaves any species at a disadvantage. All we can universally agree on is that getting it on is pretty awesome, even science can’t really argue with that.

12. No one can explain exactly how or why gravity works

We’re all pretty familiar with Newton’s gravity story. He saw the apple fall from the tree and bingo! That got gravity all neatly packaged up for him, us and school teachers everywhere. Since then, we’ve spent 400 years feeling righteous and smug thinking we’re gravity geniuses. But there’s just one small problem. Scientists still can’t really explain why or how gravity works – all we really know is what it does. The major sticking point is that we don’t know what causes it. Despite over 400 years of research we’re still just guessing and waiting for an apple to land on someone else’s head for that eureka moment.

11. Scientists can’t tell us why bicycles stay upright

We’ve all experienced that first wobbly bike ride when we were young. Mums and dads watching proudly as we careered headlong into the nearest hedge or kerbside. From those early peddling days to whizzing along on mountain bikes in later life, we all assumed bikes stay upright because of balance, forward motion or because, well they just do. Turns out, no one really knows why. In 2011, red-faced physicists told the world that after 150 years of trying to figure it out, they still don’t know. For a while they thought they had the math down but someone must have forgotten to carry the one, because as of right now they are right back to basic bike math 101.

10. Science can’t explain why it takes more genes to create a tomato than a human

We like to think we’re pretty complex creatures. Highly evolved, super-intelligent and, for the most part, devilishly good-looking. But it seems at gene level, we can’t compete with the humble tomato or many other relatively simple things. The juicy, red fruits have over 30,000 genes while we’re lagging behind with an average of around 20,000 – 30,000 genes. Science could be leading us further from the answer, rather than towards it as well. Just because we’re counting the genes doesn’t necessarily mean we know what we’re counting or what genes do. This is one mystery that looks like it’s going to get a whole lot more complicated before it gets solved. In the meantime lets just carry on enjoying our marinara sauce and leave the gene count out of it.

9. Scientists are baffled by the Antikythera Mechanism

This little beauty was found in an Aegean sea shipwreck in 1900. Believed to be the world’s first ‘computer’ it holds within it technology so advanced that it really has scientists confused. We’re talking National Treasure or Indiana Jones level of archaeology here, folks. Basically the type we can all get interested in, because it’s actually pretty cool. It dates from around 100BC when life was pretty much all sandals, pottery and gladiatorial battles. So who made the Antikythera Mechanism? How the f did they get their hands on the bronze cogs needed to make it and why? After poking at the device non-stop for years and building a reproduction of it in 2007, science has some answers. We know it tracked seasons and celestial events but nothing this advanced was seen again until around the 14th century. It even has a built in instruction manual and was accurate within one degree. Despite knowing all that, scientists still don’t really know where it was made. 

8. Geologists can’t explain musical rocks

No, not that musical rock, though that probably baffles scientists too. The actual mystery is that at various locations around the world there are rocks that ring. These boulders and pebbles aren’t dialling you up on your cell, they just ring when they are hit with a hammer. Which may not sound that weird – except rocks don’t do this. In one spot in Pennsylvania geologists have found a bunch of rocks, all made of the same substance. So far, so boring. But only roughly a third of those rocks ring. The sound is the same as a bell being struck and is composed of several notes and frequencies created inside the rocks. Creepy additional fact: Where these musical rocks are found, the areas are often devoid of life.

7. There’s no clear explanation for near death experiences

Step into the light! Many people who have had a close call with death have reported strange experiences. A common near death experience usually involves the dying feeling as though they are in a tunnel of light. Sometimes they see lost loved ones or feel at peace in their final moments, only to be brought back to life. Skeptics reckon these are just hallucinations but science still can’t pin down why so many experiences follow a very similar structure. One theory is that when our hearts stop or start to fail our brain goes into overdrive firing signals at the heart to keep it going. This influx of signals could be what triggers the hallucinations.

6. After years of study, we can’t figure out why cats purr

Possibly the more important question here is: why does this matter? Surely scientists could research some more pressing issues. Such as what’s really in a Twinkie? Why do we all watch Adam Sandler movies and just what keeps Donald Trump’s hair in place? Those mysteries aside, we just can’t solve the question of why cats purr. It sounds weird, but, stranger still, not all cats do it. Lions and tigers don’t purr, but cheetahs do. We can’t even track down which bit of a cat’s anatomy is responsible for the purr.

5. We can’t explain these weird creatures found in an ancient cave in Romania

Scientists are still scratching their heads trying to suss out just what’s going on with the Movile Cave. Cut off from the rest of the world, the underground cave has been quietly going about its business for 5.5million years. During that time some weird creatures have evolved to live in the bleak, poisonous atmosphere. The air is highly toxic and nothing should be capable of living in the cave but 48 species have been found in the sulphurous hell hole. They live off a gross foam that forms on the surfaces in the underground cave, which doesn’t sound very appealing at all. Creepy added fact: most of the creatures don’t have eyes and they feel their way around in the dark with specially formed antennae.

4. Science can’t explain a yawn

Which is really weird, seeing as how I spent a lot of time yawning in science class. Go figure. Except the brightest minds in the world really can’t figure this one out. There are a few things going on here. Yawning doesn’t seem to have a purpose. Since ancient times, medical types thought we yawned to increase oxygen levels in our blood, but that all got thrown out of the window when we discovered it can actually lower the oxygen levels. Then there’s the weird way a yawn is contagious. We can even make animals yawn by yawning in front of them. The most recent research has shown the bigger your brain, the longer you yawn. But we’re still no closer to figuring out why.

3. The Naga fireballs phenomenon still has us stumped

Every year thousands of red, glowing spheres of light appear on the Mekong River in Thailand. Locals first reported the sightings and tend to believe they are supernatural beings rising up from the waters. Scientists with a firm grip on reality disagree … but they can’t prove what’s causing them either. A few theories have been offered up. These range from methane bubbles catching fire to natural plasma orbs reacting with an electric charge on the surface. Whatever is actually at work here, one thing everyone agrees on is that this natural light show is spectacular and sees tourists and locals lining the river in October and November hoping to catch a glimpse of the mysterious orbs.

2. No one knows what causes the noise behind The Hum

All over the world people are being plagued by a persistent humming sound. Not everyone can hear it and the frequency is really low. But for those that can hear it, life is pretty miserable. Localized in certain places, the most famous of which is the Taos Hum. Residents of Taos in New Mexico have been complaining about the noise since the early 1990s. Scientists tried placing sensitive recording devices in homes where the noise was being heard, but they didn’t detect anything unusual. Often these noises can be easily explained, but the strange noise in Taos is still a mystery despite many investigations.

1. Science is mostly confused about your brain

Where to start with this one? The most mind-blowing thing science can’t explain is our actual minds. Our brains are so complex, we’re struggling to really understand why they work in the way that they do. Let’s break it down a bit and look at each mystery doctors are grappling with. Firstly, our brains are divided up into sections for specific jobs but that all seems unnecessary. Each compartment is essentially the same and sometimes the brain can reassign a compartment – after an injury, for example. Secondly, scientists have brain waves mostly figured out. When they happen, what they match up with and what activities spark them. Just one problem, they have no idea why they appear in specific patterns. Add in the curveballs thrown in by things such as the placebo effect, where we seem to feel better because we think we should and, well, it all just starts to make your brain hurt. Which is probably why scientists will still be piecing this puzzle together for many years to come.

Sources: mentalfloss.com, sciencemag.org, bbc.co.uk