10 Things Scientists Still Can’t Fully Explain


The last decade may not have been the best time for everyone, though for science, it may have been our biggest leap into the future yet. With massive leaps in fields such as AI, quantum computing, space research and medicine, among countless others, we’re finally close to solving some of our world’s most enduring mysteries. 

Some mysteries, though, are so persistent that modern-day science still has little to no explanation for them. Many of what you’d consider common, everyday concepts are actually baffling secrets of nature we’ve been trying to figure out for a while, though to little success. 

10. Flowers

Flowering plants – collectively known as angiosperms – make up about 90% of all plant species on Earth. That includes all the major crop species, making them essential for life on Earth as we know it.

Evolutionarily speaking, though, flowering plants remain a huge anomaly in our understanding of evolution. For one, they simply didn’t exist for almost all of Earth’s history. Before they showed up around 100 million years ago, Earth’s landscape was covered with moss-like species (and later conifers) which are now only restricted to some parts of the world. 

The most baffling part, though, is that we don’t know anything about their origins, or how they managed to diversify and invade environments where other plant species were already thriving so quickly. The takeover of the flowering plants was rapid and total, which flies in the face of Darwin’s theory of gradual evolution, who went as far as to call it ‘an abominable mystery‘. Even today, angiosperms are the dominating species in many isolated ecosystems where they shouldn’t be successful at all.

9. Memory

Remembering something from memory doesn’t seem to be a complicated task. Almost everyone can do it in less than a second, even if the accuracy of what you remember may depend on other factors. 

What we don’t know, though, is that the simple procedure of remembering things is also one of neuroscience’s biggest mysteries. While we have a fair understanding of how the brain forms memories, we simply don’t get how it retrieves them. 

The processes that allow the brain to send a signal to where the memory is located and get it to the front row are still unknown. That’s also why we don’t fully understand diseases like Alzheimer’s, as they directly affect our ability to retrieve stored memories. 

8. Turtles

On the face of it, sea turtles don’t come across as particularly noteworthy creatures. They’re found in a variety of habitats around the world and mostly mind their own business, making them seem like they belong where they are.  

Ask an evolutionary biologist, though, and you’d realize that turtles are another one of those evolutionary mysteries that we just haven’t got around to fully solving yet. Currently, we don’t know where to place turtles on the evolutionary tree, as we’ve never found a true common ancestor that fits them. While some studies claim that their closest relatives are crocodiles, dinosaurs, and modern bird species, others place them more closely to lizards and snakes. Some biologists are of the view that turtles diverged much earlier in the reptile family tree, though we don’t know enough about the earliest reptiles to be able to say for sure. 

7. Gravity

Gravity is one of those persistent mysteries of science that manage to get more baffling the more we try to understand them. Just take the fairly recent discovery of gravitational waves – a concept theorized by Einstein and proven almost a century later in 2015 – which was supposed to give us more answers than questions. Yet, we’ve since found multiple bursts of gravitational waves from various corners of the world that just don’t make sense. The more we find out about how gravity works out in the rest of the universe, the more we realize that it’s the weirdest force we know of. 

The fundamental problem with gravity is that it’s the weakest type of force, which makes it impossible to detect and study in the lab. It only seems strong because it’s accumulative and doesn’t have positive-negative particles that could cancel each other out. Despite its weakness, that one property allows it to be the dominant force in the universe.

On top of that, we still don’t know what part of matter it is that emits gravitational waves and causes gravity in the first place. Because it’s so weak, any such particle would be almost impossible to detect with our current equipment. 

6. Viruses

With the coronavirus pandemic still raging in many parts of the world, you can’t help but think about how a pesky virus got the better of us, what with all of our advanced medical tech. While it’s true that we could have done more to stop it from getting so bad, we won’t be that quick to blame anyone but the virus. 

Viruses are, in themselves, mysterious creatures that we know shockingly little about. To start with, they’re not even technically alive. Viruses are essentially blobs of biological material that only activate inside a host, and have no ability to reproduce or replicate without it. We also don’t have any idea where they originated from, and have still not been able to accurately place them on the tree of life. 

Some theories suggest that they’re remnants left over from the millions of years of evolution of cellular organisms. Others say that they may be a distinct type of life that predates every biological creature we know of and may be responsible for life on Earth as we know it.

5. Bipedalism

Standing up and walking on two feet may have been the single most crucial point in our evolution. While there are other apes that can stand up for prolonged periods of time, it’s only humans that permanently got up on our own two feet – so to speak – and never looked back. That one decision freed our hands to build better weapons and tools, giving us a massive edge over our less fortunate four-legged brethren. 

If you look at it from an evolutionary perspective, though, bipedalism is actually a poorly-misunderstood step in the course of our evolution. We’re not entirely sure why – or even when – hominid species started doing it. For our earliest bipedal ancestors, it would have been a massive disadvantage to expose themselves to other predators by standing up on two feet, among other massive problems that come with walking on two feet. As we mentioned before, other apes already knew how to walk on two feet whenever they wanted, though none of them chose to adopt it as a permanent lifestyle as it offers no immediately-apparent advantage. Except us. 

Moreover, there’s a massive gap in the fossils we’ve found from the time primates started to develop bipedalism, further casting a shadow on the circumstances that led us to develop this unique, game-changing trait. 

4. The Sun

Understandably, the sun is a bit difficult to study because of being a giant ball of burning-hot plasma. Still, you’d think that we know a bit about the only star of our solar system, as well as the primary source of energy on Earth.

As you’d expect from the theme of this list, that’s not really the case. In fact, as our equipment gets better and closer to the surface of the sun than ever before, we realize that it’s actually one of the most mysterious objects in the solar system.

For one, the sun is unusually hot, and yes, that’s considering that it’s already a giant celestial ball that’s constantly burning. The surface of the sun usually sits at around 10,000 degree Fahrenheit, though it’s atmosphere is around a million degrees. We think that it’s because of some other mysterious energy released by the sun’s core, though again, we’re only guessing here. 

Another mystery is the solar winds consistently emanating out of it. While we know the origins of the faster, supersonic winds we’ve observed before, some recent studies have found another, slower variety of the winds whose origins are a total mystery.

3. Water

We know that water is – by far – the most common substance found on Earth, as around 71% of Earth’s surface area is covered in it. It’s also the biggest reason life exists; we don’t know of any life form that isn’t water-based.

If you take some time to look into it, though, you’d find out that all of that isn’t because it’s a perfectly normal thing found on Earth. Water is, in every way, the weirdest naturally-occurring substance we know of, with properties so peculiar that we don’t know of anything else that resembles it. 

To begin with, water is the only substance that stably exists in all of its states – solid, liquid, and gas. That is, of course, if we knew all of its states, as scientists recently discovered that liquid water can exist in multiple, distinct states each with unique properties of their own. 

Water is also the only substance which expands when it cools, and vice versa. That may seem like just a cool fact, but that one property allows floating ice on giant water bodies to keep the water under the surface a bit warmer than usual, as it works as an insulator. Because of that, rivers and lakes always freeze from the top down, which would have allowed complex life to survive under the surface during the many ice ages. 

Another unique property of water is its unusually high surface tension. It requires a ridiculously-high amount of energy to separate water molecules compared to other liquids, and we simply don’t understand why. 

2. Laughter

Laughter is a fairly regular part of most of our lives, as we don’t even think about how many times we laugh in a day, as it comes and goes as a reflex. 

If we talk about the biological mechanisms that trigger laughter, though, there’s still surprisingly little we know about them. Even if we know that a huge part of the brain lights up when we laugh – often involving other parts of the body like legs – we’re not sure exactly which of those parts are actually involved in the whole process. 

Moreover, we don’t know when we laugh, either. It has nothing – or, at least, very little – to do with humor, as most laughter is in response to social cues or sentences that aren’t in themselves funny. In a study on 2,000 cases of naturally occurring laughter, researchers found that most laughter was in response to contextual, social cues that may not elicit any response in a different situation. 

1. Sex

Sexual reproduction makes perfect sense on paper. It’s a great way to weed out hereditary diseases, rapidly produce a lot of new babies compared to sexual reproduction, and – most importantly – feels amazing. 

If we trace its evolutionary history, though, sex doesn’t make a lot of sense. Sexual reproduction comes with the enormous cost of one half of the population – males – not producing any offspring. For the argument that it helps keep harmful genetic mutations in check, that only works if the mutations occur frequently. According to one study, the rate of mutation in most species is too less to justify the high cost of sexual reproduction.

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  1. I hate to be technical, but #6. The sun is not burning. It’s undergoing runaway thermonuclear chain reaction.

    • I love to be technical. Technically, you’re referring to topic number 4. Topic number 6 is viruses.

      Per NASA: “People, including scientists, sometimes say that the Sun “burns hydrogen” to make it glow. But that is just a figure of speech. Hydrogen really doesn’t burn, it fuses, into helium. So no oxygen is required!” A figure of speech is a word or phrase used in a non-literal sense for rhetorical or vivid effect.

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