From the subatomic particles that compose the fabric of our universe to the intricate mechanisms driving life on Earth, science empowers us to unravel the mysteries that surround us.
With this in mind, here are a couple of amazing scientific facts that I hope will inspire you to learn something new every day — they’ve certainly done so for me. However, this list is much too short; keep it growing by adding your own interesting science facts in the comments section.
1. There is enough DNA in the average person’s body to stretch from the sun to Pluto and back — 17 times
The human genome (the genetic code in each human cell) contains 23 DNA molecules (called chromosomes), each containing from 500,000 to 2.5 million nucleotide pairs. DNA molecules of this size are 1.7 to 8.5 cm long when uncoiled — about 5 cm on average.
There are about 37 trillion cells in the human body, so if you were to uncoil all of the DNA encased in each cell and place the molecules end to end, it would sum to a total length of 2×1014 meters — enough for 17 round trips to Pluto (the distance from the sun to Pluto and then back again is 1.2×1013 meters). As an added bonus, you should know that we each share more than 99% of our DNA with every other human — just to show that we’re far more alike than different.
2. The average human body carries ten times more bacterial cells than human cells
It’s funny how we compulsively wash our hands, spray our countertops, or make a grimace when someone sneezes near us, when, in fact, each and every one of us is a walking petri dish! All the bacteria living inside you could fill a half-gallon jug — there are 10 times more bacterial cells in your body than human cells, according to Carolyn Bohach, a microbiologist at the University of Idaho. Don’t worry, though: most of these bacteria are helpful. In fact, we couldn’t survive without them.
For example, bacteria produce chemicals that help us harness energy and nutrients from our food. Germ-free rodents have to consume nearly a third more calories than normal rodents to maintain their body weight, and when the same animals were later given a dose of bacteria, their body fat levels spiked despite the fact that they didn’t eat any more than they had before. Gut bacteria are also very important for maintaining immunity. (image source).
3. It takes a photon up to 40,000 years to travel from the core of the sun to its surface, but only 8 minutes to travel the rest of the way to Earth
A photon travels, on average, a particular distance before being briefly absorbed and released by an atom, which scatters it in a new random direction. To travel from the sun’s core to the sun’s surface (696,000 kilometers) so it can escape into space, a photon needs to make a huge number of drunken jumps.
The calculation is a little tricky, but the conclusion is that a photon takes many thousands and many millions of years to drunkenly wander to the surface of the Sun. In a way, some of the light that reaches us today is energy produced millions of years ago. Amazing!
4. At over 2,000 kilometers long, The Great Barrier Reef is the largest living structure on Earth
Coral reefs consist of huge numbers of individual coral polyps (soft-bodied, invertebrate animals) that are linked together by tissue. The Great Barrier Reef is an interlinked system of about 3,000 reefs and 900 coral islands divided by narrow passages, located just beneath the surface of the Coral Sea. Spanning more than 2,000 km and covering an area of some 350,000 sq km, it is the largest living structure on Earth and the only one visible from space. However, this fragile coral colony is beginning to crumble, battered by the effects of climate change, pollution, and manmade disasters.
5. There are 8 times as many atoms in a teaspoonful of water as there are teaspoonfuls of water in the Atlantic Ocean
Here’s a fun science fact that will get the ball rolling during your next water cooler conversation. A teaspoon of water (about 5 mL) contains 2 x 1023 water molecules, but each water molecule is comprised of 3 atoms: two hydrogen atoms and one oxygen atom. Moreover, if you’d laid down end to end each water molecule from a teaspoon down end to end, you’d end up with a length of 50 billion km — 10 times the width of our solar system.
6. In an entire lifetime, the average person walks the equivalent of five times around the world
The average moderately active person takes around 7,500 steps per day. If you maintain that daily average and live until 80 years of age, you’ll have walked about 216,262,500 steps in your lifetime. Doing the math; the average person with the average stride living until 80 will walk a distance of around 110,000 miles — which is the equivalent of walking about 5 times around the Earth, right on the equator.
7. There are actually over two dozen states of matter (that we know of)
Everybody knows that there are at least three states of matter: solid, liquid, and gas. If you’re a little bit more versed in physics, you also know about the fourth fundamental state of matter called plasma — a hot ionized gas, with prime examples including lightning or neon signs.
But beyond these common states of matter, scientists have discovered a myriad of exotic states of matter that occur under special conditions. Here’s a fun science fact to remember: in Bose-Einstein condensates, atoms are chilled to only 0.000001 degrees above absolute zero and start behaving like waves, rather than particles as they ought to on the macroscopic scale. Essentially, the atoms behave like one super atom, acting in unison.
Another interesting exotic state of matter is represented by time crystals — regular, boringly ordered crystals with a twist: A fourth dimension, time, is added so that the material exhibits different periodic structures over time. What makes these crystals particularly remarkable has less to do with the fact that they repeat in time but rather more with the fact that they’re intrinsically out of equilibrium. Because time crystals are never able to settle down, say into a diamond or ruby, there’s a lot we can learn from them.
8. Killer whales are actually dolphins
Despite their name, killer whales or orcas are the largest members of the dolphin family. Technically, orcas are also whales because delphinids belong to the Cetacean order within the toothed whale (Odontoceti) suborder. However, the term whale is typically reserved for baleen whales of the Mysticeti suborder.
The major physical feature that ensures orcas are dolphins is the presence of a melon — a fatty deposit that assists the animals in echolocation and only exists in dolphins.
Orcas are highly intelligent, highly adaptable, and able to communicate and coordinate hunting tactics. They are extremely fast swimmers and have been recorded at speeds of up to 54 kph! A wild orca pod can cover over 160 kilometers a day, foraging and socializing.
9. Grasshoppers have ears in their bellies
Unlike humans, grasshoppers do not have ears on the side of their heads. Like the ears of people, the grasshopper sound detector is a thin membrane called a tympanum, or “eardrum”. In adults, the tympanum is covered and protected by the wings, and allows the grasshopper to hear the songs of its fellow grasshoppers.
The grasshopper tympanum is adapted to vibrate in response to signals that are important to the grasshopper. Male grasshoppers use sounds to call for mates and to claim territory. Females can hear the sound that males make and judge the relative size of the male from the pitch of the call (large males make deeper sounds). Other males can hear the sounds and judge the size of a potential rival. Males use this information to avoid fights with larger male grasshoppers or to chase smaller rivals from their territory.
10. You can’t taste food without saliva
In order for food to have taste, chemicals from the food must first dissolve in saliva. It’s only once they’ve been dissolved in a liquid that the chemicals can be detected by receptors on taste buds. During this process, some salivary constituents chemically interact with taste substances. For example, salivary buffers (e.g., bicarbonate ions) decrease the concentration of free hydrogen ions (sour taste), and there are some salivary proteins that may bind with bitter-taste substances.
Here’s a quick science experiment to test this out — get out a clean towel, and rub your tongue dry; then place some dry foods on your tongue, one by one, such as a cookie, pretzel, or some other dry food. After this session, drink a glass of water and repeat. Did you feel a difference?
11. When Helium is cooled to almost absolute zero (-460°F or -273°C, the lowest temperature possible), it becomes a liquid with surprising properties: it flows against gravity and will start running up and over the lip of a glass container!
We all know helium as a gas for blowing up balloons and making people talk like chipmunks, but what most people don’t know is that it comes in two distinct liquid states — one of which is borderline creepy. When helium is just a few degrees below its boiling point of –452°F (–269°C), it can suddenly do things that other fluids can’t, like dribble through molecule-thin cracks, climb up and over the sides of a dish, and remain motionless when its container is spun. No longer a mere liquid, the helium has become a superfluid — a liquid that flows without friction.
“If you set [down] a cup with a liquid circulating around and you come back 10 minutes later, of course, it’s stopped moving,” says John Beamish, an experimental physicist at the University of Alberta in Edmonton.
This happens because atoms in the liquid will collide with one another and slow down.
“But if you did that with helium at low temperature and came back a million years later,” he says, “it would still be moving”.
12. If Betelgeuse exploded, transitioning from the red supergiant stage to supernova, it would light our sky continuously for two months. It could happen anytime — within a couple of thousand years, tomorrow or even now
Betelgeuse lies some 430 light-years from Earth, yet it’s already one of the brightest stars in Earth’s sky. The reason is that Betelgeuse is a supergiant star — the largest type of star in the Universe. Betelgeuse has a luminosity about 10,000 times greater than that of the Sun and its radius is calculated to be about 370 times that of the Sun. If it were positioned at the center of our sun, its radius would extend out past the orbit of Mars. Because it’s near the end of its lifetime, Betelgeuse is likely to explode into a supernova.
13. Octopuses have three hearts, nine brains, and blue blood
Two of the hearts work exclusively to move blood beyond the animal’s gills, while the third keeps circulation flowing for the organs. When the octopus swims, the organ heart stops beating, which explains why these creatures prefer to crawl rather than swim (it exhausts them).
An octopus also has nine brains — well, sort of. There’s one ‘main’ brain where all the analysis and decision-making takes place and eight ancillary brains — one at the base of each arm — that function as preprocessors for all the information obtained by that arm. Two-thirds of an octopus’s neurons reside in its arms, which can independently figure out how to open a shellfish, for instance, while the main brain is busy doing something else.
Our blood is red due to the fact that it contains iron-based hemoglobin to transport oxygen to cells. Octopuses, on the other hand, use the copper-based cyanoglobin, which performs the same function, albeit less efficiently — this makes octopuses have less stamina than you might expect.
14. An individual blood cell takes about 60 seconds to make a complete circuit of the body
You have about 5 liters of blood in your body (at least, most people do) and the average heart pumps about 70 mL of blood out with each beat. A healthy heart also beats around 70 times a minute. So, if you multiply the amount of blood that the heart can pump by the number of beats in a minute, you actually get about 4.9 liters of blood pumped per minute, which is almost your whole body’s worth of blood. In just a minute, the heart pumps the entire blood volume around your body. During an average lifetime, the human heart will beat about 3 billion times.
15. The known universe is made up of 50,000,000,000 galaxies.
There are between 100,000,000,000 and 1,000,000,000,000 stars in a normal galaxy. In the Milky Way alone there might be as many 100 billion Earth-like planets. Still think we’re alone?
16. Hot water freezes faster than cold water
In certain conditions, hot water can freeze faster than cold water — a counter-intuitive phenomenon known as the Mpemba effect. There is a number of proposed explanations for the Mpemba effect, including faster evaporation of hot water that reduces the volume left to freeze, the formation of a frost layer on cold water that insulates it, or different concentrations of solutes such as CO2. The phenomenon is named after schoolboy Erasto Mpemba from Tanzania, who in the 1960s claimed in his science class that ice cream would freeze faster if it was heated first before being put in the freezer.
17. About 1% of our genes come from plants, fungi, and other germs
According to research from the University of Cambridge, humans have evolved with genes acquired from plants and fungi. But how did they get there? Rather than a straightforward single-branching tree where genes are inherited from parents, scientists argue that sometimes foreign genes may spread by a process known as horizontal gene transfer. For instance, different species of bacteria often exchange genes via viruses.
18. The human brain can store as much information as the entire Internet
A 2016 study by biologists at the Salk Institute in La Jolla, California, shook the field of neuroscience, finding that the human brain’s memory capacity exceeded previous conservative estimates by a factor of 10. They calculated that the typical human brain could store one petabyte of information or a quadrillion bytes. To put this figure into perspective, that’s about as much information as was contained on the entire internet in 2016.
19. The tallest mountain in the solar system is Olympus Mons on Mars
Olympus Mons is a massive shield volcano located on the planet Mars. It is the largest volcano and the second-highest mountain in the Solar System, towering at an elevation of about 22 kilometers (14 miles) above the Martian surface. It is about 600 km (370 mi) in diameter and has a caldera 80 km (50 mi) wide.
Olympus Mons is located in the Tharsis volcanic plateau, which is one of the most geologically active areas on Mars. The volcano is thought to have been formed by a hot spot in the Martian mantle, which has been spewing lava for millions of years, building up the volcano’s immense bulk. The volcano has been inactive for a very long time, but it’s still one of the most interesting places to study on Mars, as it could have potential signs of past microbial life or still-existing subsurface water.
Exploring Olympus Mons would be extremely challenging, but it would also be a key place to visit if we are to learn more about the geology, and even potential signs of past or present life on Mars.
20. Our planet is home to around 8.7 million different species
This number is a rough estimate, as scientists have not yet discovered or cataloged all of the living species on Earth. This number also keeps on changing as new species are discovered and others become extinct. Actually, some scientists believe that the majority of Earth’s species have yet to be discovered, with many estimates suggesting that the true number of species on Earth could be as high as 50-100 million.
This diversity of life is spread across different habitats on Earth, such as forests, deserts, oceans, and freshwater systems. But it’s worth mentioning that many species are facing extinction due to human activities such as habitat loss, pollution, and climate change.
21. Every second, the sun emits more energy than humanity has used since the dawn of civilization
The sun emits a tremendous amount of energy in the form of electromagnetic radiation, particularly in the form of visible light and ultraviolet radiation. The total amount of energy that the sun emits each second, known as the solar constant, is roughly equal to 3.8 x 10^26 watts. This is a huge number, and it’s difficult to comprehend the scale of energy that we’re talking about. To put it in perspective, humanity has used around 10^20 joules of energy since the dawn of civilization, which is roughly equivalent to 10^17 watts-hours.
22. The longest-living cells in the body are neurons, which can live as long as your lifespan
Unlike some other cells in the body, such as blood cells or skin cells, neurons are not regularly replaced. Once they are formed during early development, they can survive for the entire lifetime of an individual. This is due to several reasons such as the fact that neurons have low rates of mitosis, a high resistance to damage, and a structural support called neuroglia which helps to protect the neurons from harmful effects such as toxic substances or physical damage.
This is also the reason why neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease have a huge impact as once neurons die they are not replaced at a sufficient rate to replenish cognitive function.
What’s next? Add your interesting science facts in the comments below.