10. Earth isn’t round
Don’t worry – we’re not about to tell you that the Earth is flat, but did you know that our planet is not perfectly round either? The Earth is actually a type of a sphere called oblate spheroid. This means that the Earth is squashed at the poles and bulges at the equator. Because of these irregularities, the distance from the Earth’s center to sea level is around 21 kilometers (or 13 miles) greater at the equator than at the poles. While this difference cannot be seen with a naked eye, it can be easily calculated using artificial satellite techniques.
The sphere-like shape of our planet is the result of the Earth’s rotation. As the Earth spins on its axis, it produces a small equatorial bulge and slightly flattened poles due to centrifugal force. This is why a vertical cross-section through the Earth along the polar axis has the shape of an ellipse, whereas a horizontal cross-section through the Earth along the equator has the shape of a circle.
9. Gravity isn’t the same everywhere on Earth
If the Earth was perfectly round or spherical and had uniform mass density, the gravitational field would be the same at all points on its surface. But since Earth is a flattened spheroid, gravity isn’t equally distributed and its strength varies from place to place. Due to centrifugal forces produced by the planet’s rotation, gravity is at its weakest at the equator and the strongest at higher altitudes further from the Earth’s center.
This means that you would weigh 0.5% more at the poles than at the equator, while your weight would decrease by about 0.29% on the top of Mount Everest. The gravity at the top of Mount Everest is actually 99.72% as strong as the gravity at sea level, so if something weighed 1000 pounds at sea level, it would weigh only 997.2 pounds at the top of Mount Everest. So if you ever feel bad about your weight after devouring a whole pizza by yourself, just climb Mount Everest – and don’t forget to bring the scales with you!
8. Earth’s magnetic poles will soon flip
The switching of the poles sure sounds like a Doomsday scenario, but it’s actually a perfectly normal occurrence that has already happened many times in Earth’s history. Over the last 20 million years, the north and south magnetic poles have been reversing every 200,000 to 300,000 years. Since the last swap took place about 780,000 years ago, this means the next one is fast approaching. According to the latest satellite data from the European Space Agency, the magnetic field is already showing signs of shifting, but scientists still can’t say exactly when the next pole reversal will take place.
When it does happen, though, it could have serious consequences for life on Earth. The Earth’s magnetic field is a giant shield that protects our planet from harmful cosmic rays, and each time the poles switch places, this shield becomes weaker. At the moment, the dangerous radiation from space is still not hitting the surface of the Earth, but this could all change after the poles shift. Once the magnetic field gets substantially weaker and stays that way for an extended period of time, the Earth will be exposed to higher levels of radiation, which could eventually wipe out our entire power grid and lead to an increase in diseases like cancer.
7. Earth used to have two Moons
I know what you’re thinking: not another conspiracy theory about Earth! But believe it or not, our planet most likely used to have two Moons that collided and merged into one astronomical body nearly 4.5 billion years ago. The two-moon hypothesis, published in the prestigious scientific journal Nature in 2011, provides an explanation for the noticeable differences between the Moon’s two hemispheres.
The hemisphere facing the Earth is covered by low, lava-filled plains, whereas the “dark side of the Moon” is made up of rugged, rocky highlands. Those highlands, according to the two-moon hypothesis, are the remains of the smaller, short-lived satellite that collided with the Moon as we now know it. Since the two moons collided at subsonic speeds, there was no explosion and the merging was almost fluid. The two-moon hypothesis is yet to be experimentally proven, but upcoming lunar missions will probably help settle the question of whether the moon once had a little brother.
6. The highest point on Earth is not Mount Everest
You were probably taught at school that Mount Everest is the highest mountain in the world – which is true – but did you know that this doesn’t mean that Mount Everest is also the highest point on Earth? This title actually belongs to Chimborazo, a volcano located in the Cordillera Occidental, one of the two main mountain ranges of the Andes in Ecuador. So how is it possible that the highest mountain on Earth and the Earth’s highest point are two different things? As you’re probably already guessing – the reason once again lies in the irregular shape of our planet.
With a maximum height of 6,263 meters, Chimborazo is not the highest mountain by elevation above sea level, but its location on the equatorial bulge makes its summit the farthest point on the Earth’s surface from the Earth’s center, as well as the point on Earth closest to the moon. But Chimborazo is not the only mountain to challenge Mount Everest’s title as the highest on the planet. Hawaii’s dormant volcano Mauna Kea is actually a lot bigger from top to bottom than Everest – but since its bottom is located under the sea Mount Kea can’t match Everest’s record-breaking height when measured in relation to sea level.
5. A day on Earth is not exactly 24 hours
It’s common knowledge that there are 24 hours in one day. Or are they? What if I told you one day on Earth does not actually last 24 hours, but rather 23 hours, 56 minutes, and 4 seconds. A day is the period of time during which the Earth completes one rotation around the Sun and for all intents and purposes this interval is equal to 24 hours. However, this period of rotation actually lasts about 4 minutes less than 24 hours.
You might be wondering now why doesn’t time of day shift in relation to daylight if an actual day is 23 hours, 56 minutes, 4 seconds? If there’s an extra 3 minutes and 56 seconds every day, midnight would eventually be in the middle of the afternoon, right? Well, not really. The simple answer is that there are actually two different types of days: a sidereal day and a solar day. A sidereal day is the period it takes the Earth to rotate 360 degrees on its axis and this takes less than 24 hours. However, this is not what most of us refer to when we use the word ‘day’ in everyday speech. What we’re actually talking about is the solar day, or the period of time it takes for the Sun to end up in the same spot in the sky, which is almost exactly 24 hours. If that sounds strange and confusing, wait till you hear about the last four things on our list!
4. Earth is made up of two planets fused together
Not only is there a possibility that the Earth used to have two Moons, but our planet itself might be the product of a similar collision. Researchers from the University of California, Los Angeles have found evidence that a small planetary object named Theia smashed into Earth around 4.5 billion years ago and fused with our planet in a violent collision. Scientists believe that the material thrown into orbit after this collision formed the two moons that later merged into one. Theia was an object about the size of Mars, with a diameter of about 6,102 km. It is named after the mother of Selene, the goddess of the Moon in Greek mythology.
According to this hypothesis, Theia orbited the Sun along the orbit of the proto-Earth before eventually being pushed away by the gravitational influence of Jupiter and Venus, resulting in a collision with Earth. The smaller planet’s core mixed with the Earth’s core, which would explain why the Earth’s core is now larger than it is normally expected for an astronomical body of its size.
3. The largest living organism on Earth is a fungus
Yes, the largest living animal on the planet is the blue whale, but if we’re talking about all forms of life on Earth, then the title of the largest one goes to a gigantic species of fungus discovered in the Blue Mountains in Oregon, United States.
Armillaria ostoyae is a species of plant pathogenic fungus that attacks the sapwood and is able to travel great distances under the bark or between trees. A single specimen of this mammoth fungus found in Malheur National Forest in Oregon covers 3.4 square miles and is thought to be somewhere between 1,900 and 8,650 years old. When this giant mushroom – nicknamed the “Humongous Fungus” – was first discovered in 1998, it sparked the debate about what constitutes an individual organism. However, scientists have since come to the conclusion that if a being has a set of cells that are genetically identical and can communicate to each other, it can be classed as one single organism, which makes the “Humongous Fungus” the largest known organism in the world by area it covers.
2. 95% of Earth’s oceans are unexplored
Despite all of our technological advances, the Earth’s oceans remain largely mysterious. Even though the ocean covers more than 70% of the planet’s surface, we have explored less than 5% of it. In fact, we know more about the Moon than about the deepest parts of the ocean! This means that there could be an endless number of strange and fascinating things waiting to be discovered in the unexplored depths of the ocean.
To get an idea of just how unknown the ocean is, consider this: in 2004 a team of explorers working on a project called Operation Deep Scope placed a hidden camera on the bottom of the deep ocean in the Gulf of Mexico and made a new discovery almost immediately. It took less than a minute for the camera to capture a video of a six-foot squid that had never been seen before and was not known to exist. Imagine only what other exciting discoveries we could make if we were to explore the whole of ocean floor!
1. Earth harbors life in the most inhospitable places
Without a doubt, the strangest and most remarkable thing about planet Earth is its capacity to support life in the most unlikely of places. Let’s look at just some of the examples of how organisms can adapt to life under most inhospitable conditions.
Lake Vostok, the largest of Antarctica’s lakes, contains an environment that has been sealed off below the ice for about 15 millions of years. The average water temperature in Lake Vostok is around −3 °C, but the lake remains liquid below the normal freezing point because of high pressure from the weight of the ice above it. The lake contains 50 times more nitrogen and oxygen than is typically found in ordinary freshwater lakes on Earth’s surface. It is also located in complete darkness, under 355 bar of pressure. Despite extremely high pressure, constant cold, few nutrient sources, and absence of sunlight, scientists have discovered at least 3500 unique genetic sequences belonging to microbes that live in the lake. Other extreme environments where it was once thought that no organism could survive include the Danakil Depression in Ethiopia where microorganisms live in pure acid, underwater hot springs in the Pacific Ocean where bacteria thrive in boiling water, and the Chernobyl Exclusion Zone where plants and animals have adapted to ionizing radiation.