20 Interesting Facts About Earth You May Not Know

The Earth is a bright blue marble, captivating humanity since the first time humans set foot on its surface. The Earth is not only a place where humans can live – it is also known as the origin of life and the only planet that hosts life. Over the centuries, we have learned a lot about the Earth – a planet that continues to fascinate us.

But how many people truly understand the Earth planet? Since birth, we have lived on this planet, but do we really comprehend the ground beneath our feet? The Earth – our “green home” is filled with strange and fascinating stories that not everyone knows, and here are 10 facts about the Earth that you should know.

1. Plate tectonics keep the planet “comfortable”

The Earth is the only planet in the solar system with tectonic plates. Essentially, the Earth’s outer shell is divided into many parts called “tectonic plates“. These plates float on the Earth’s magma and can move relative to one another. When two plates collide, one plate is pushed back (downward beneath the other plate), and where they separate, new crust is formed.

The tectonic plates of the Earth. (Source: msnucleus.org).

This process has several important reasons. It not only reshapes the surface and geological activity (such as earthquakes, volcanic eruptions, mountain formation, and ocean trench formation), but it is also part of the carbon cycle. When tiny plants in the ocean die, they fall to the ocean floor.

Over a long time, these remnants of life, a significant amount of carbon, are pushed back into the Earth and recycled. This process removes carbon from the atmosphere, ensuring that we do not suffer from the uncontrolled greenhouse effect found on Venus, making the Earth a “terribly” hot place.

2. Earth is nearly spherical

People have always believed that The Earth is a sphere. In reality, this understanding was only accepted by science in the 6th century BC and in modern times. Nowadays, thanks to modern astronomy and space travel, scientists have discovered that the Earth is shaped like a flattened sphere (known as an oblate spheroid).

The Earth resembles a sphere, with flattened poles and a bulging equator. This bulging is due to the rotation of the planet. This means that the distance from one pole to the other is about 43 km shorter than the diameter that passes through the Earth’s equator. Although the highest mountain on Earth is Mount Everest, when measured from the center of the Earth, Mount Chimborazo in Ecuador is actually the highest.

The layers of the Earth include: inner core, outer core, mantle, and crust. (Source: discovermagazine.com).

3. The composition of the Earth is mostly iron, oxygen, and silicon

When analyzing the materials that make up The Earth, you will find 32.1% iron, 30.1% oxygen, 15.1% silicon, and 13.9% magnesium. Of course, most of the iron is located in the Earth’s core. In fact, studies have shown that the core of the Earth contains 88% iron, while the Earth’s crust is 47% oxygen.

4. 70% of the Earth’s surface is water

Astronauts who first ventured into space viewed The Earth with their eyes and referred to it as the “Blue Planet“. This is understandable since 70% of our planet is covered in water, while 30% consists of solid land above sea level. Hence, this is why it is called the “continental crust“.

5. The Earth’s atmosphere extends up to 10,000 km

The atmosphere of The Earth is thickest within the first 50 km from the surface, but it actually extends up to 10,000 km into outer space. The Earth consists of five main layers – the top of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. According to the laws of air pressure and decreasing density, the air pressure entering the atmosphere is higher, hence the surface density is thicker.

Earth observed from the Apollo spacecraft cabin. (Source: NASA).

The majority of the Earth’s atmosphere is located just above the surface. In fact, 75% of the Earth’s atmosphere resides within the first 11 km above the planet’s surface. However, the exosphere is the largest layer, extending from the exobase – located at the top of the thermosphere at an altitude of about 700 km above sea level – to about 10,000 km (6,200 miles) above sea level. The exosphere is the empty space layer of outer space, where there is no atmosphere.

The exosphere mainly consists of extremely low-density hydrogen, helium, and some heavier molecules such as nitrogen, oxygen, and carbon dioxide. Atoms and molecules are spaced far apart; the exosphere is not a place for gas activity, and molecular particles continuously escape into space. These molecular particles move freely along ballistic trajectories and can move in and out of the magnetosphere or with the solar wind.

6. The molten iron core of the Earth creates a magnetic field

The Earth is like a gigantic magnet with two poles located at either end – near the actual geographic poles. The magnetic field extends thousands of kilometers beyond the Earth’s surface – forming an area called the “magnetosphere“. Scientists believe this magnetic field is generated by the molten outer core of the Earth – where heat causes the convective motion of conductive materials to produce electric currents.

Image of Earth’s protective magnetic field and the dynamo effect in the core that generates the magnetic field. (Source: ESA / ATG medialab).

Understanding the magnetosphere is crucial. Without the magnetosphere, molecular particles from the solar wind would directly blow into the Earth, introducing a large amount of radiation to the planet’s surface. Instead, the magnetosphere deflects solar wind around the Earth, protecting us from health hazards. Scientists also hypothesize that the thin atmosphere of Mars is due to a weaker magnetosphere compared to that of the Earth – allowing the solar wind to gradually strip it away.

7. The Earth Rotates Around Its Axis in Less Than 24 Hours

In reality, the Earth takes only 23 hours, 56 minutes, and 4 seconds to complete one rotation on its axis – astronomers refer to this as an “astronomical day“. This does not mean that our days are shorter by 4 minutes. The excess time accumulates over days and months – day becomes night and night becomes day.

Remember that the Earth orbits the Sun. Each day, the Sun moves slightly against the background stars in the sky by about 1⁰ – roughly the size of the Moon in the sky. Thus, if we add the Sun’s motion, we see that the Earth’s rotation around the Sun, as well as its axis, results in a total time of 24 hours.

This is referred to as a “solar day” – different from an “astronomical day” – which is the time it takes for the Sun to return to its previous position in the sky. The difference between them is the time it takes for the stars to appear in the same position in the sky compared to the rising and setting positions of the Sun.

8. A Year on Earth is Not Exactly 365 Days

In fact, a year on Earth is approximately 365.2564 days. The remaining 0.2564 days leads to an extra day added every 4 years, known as a leap year. This is why every four years, an additional day is added to February, such as in 2004, 2008, 2012, etc. The exception to this rule occurs when the year is divisible by 100 (like 1900, 2100) but not by 400 (like 1600, 2000).

9. Earth Has One Moon and Two Co-Orbital Satellites

As you may know, Earth has only one Moon. But did you know that our planet also has two other asteroids sharing its orbit? They are known as 3753 Cruithne (an asteroid in the main belt orbiting the Sun) and 2002 AA29 (a near-Earth object about to be captured as a satellite by Earth), most of which are classified as Near-Earth Objects (NEOs).

The asteroid 3753 Cruithne is about 5 km long and is sometimes referred to as the “second moon of Earth“. In reality, it does not orbit Earth but follows a synchronized orbit with our planet. Moreover, this orbit makes it appear to trail Earth in the same orbital path, but in reality, it follows its own unique orbit around the Sun.

Meanwhile, 2002 AA29 is about 60 meters long and has a horseshoe-shaped orbit around Earth, coming close to our planet once every 95 years. It appears around Earth in the same orbital ring only once every 600 years. Scientists believe it could serve well for space exploration missions.

10. Earth is the Only Planet Known to Support Life

We have discovered evidence of water and organic molecules on Mars and the building blocks of life on the moons of Saturn. Amino acids have been observed in distant cosmic nebulae. Scientists are investigating where life might exist beneath the icy crust of Jupiter’s moon Europa and Saturn’s moon Titan. However, Earth remains the only planet known to support life.

Scientists are establishing laboratories to find other planets that may harbor life. For example, NASA recently announced the creation of the Nexus for Exoplanet System Science (NExSS) – dedicating the coming years to studying data collected by the Kepler Space Telescope (other missions yet to be announced) and signs of life on exoplanets.

Icy surface of Europa observed by NASA’s Galileo spacecraft in 1998. (Image source: NASA / JPL-Caltech / SETI Institute).

Recently, giant radio dishes have been scanning distant stars, collecting special signals for intelligent life reaching out into interstellar space. New telescopes like NASA’s James Webb Space Telescope, the Transiting Exoplanet Survey Satellite (TESS), and the European Space Agency’s Darwin mission could be advanced enough to detect life on other planets.

But interestingly: “Earth remains the only planet known to support life.”

11. The Planet Emits Radiant Energy

A 2011 study showed that Earth emits heat reaching up to 40 TW (terawatts), with half of this coming from radioactive decay in the Earth’s core. Most of the heat supporting all life on our planet originates from the radioactive decay of elements like thorium, uranium, and potassium.

12. Life Exists at the Ocean Floor

The sediment at the ocean floor is home to approximately 2.9×10²⁹ microorganisms existing at a depth of 2.5 km below the sea surface. The ecosystem here develops much slower compared to the surface marine ecosystem. Scientists are currently searching for more traces of life that may exist at even greater depths than previously discovered.

13. Moss is Everywhere

Moss is found all over our planet. Its ability to thrive comes from its unique structure that allows it to absorb water directly from the air through special “hairs” that grow from its leaves. For moss species living in hot, dry climates, this is a highly beneficial trait.

14. Earthquake “Weather” is Just a Myth

“Every place will have a different type of ‘earthquake weather’ to predict the time and location of an earthquake.” In reality, earthquakes are caused by fault movements occurring beneath the continental surface and are unrelated to the weather.

15. Clouds Help Regulate Earth’s Temperature

If all the water in clouds were gathered and spread over the Earth’s surface, it would cover the ground with a layer of water about the thickness of a strand of hair. This “water amount” creates the difference between summer and winter temperatures. Clouds play a crucial role in regulating the weather temperature on our planet, keeping it much cooler.

16. This Planet is 10,000 Times Older Than Humanity

The Earth has existed for about 4.5 billion years, while humans have only been around for about 450,000 years; and it was only about 45,000 years ago that humans fully populated this planet.

17. Who Named Earth?

Unlike other planets where we know the origins of their names, we have no basis to indicate “who” called our blue planet “Earth”. The term “Earth” originates from Old English and High German (part of the West Germanic languages), and it is also the only planet not named after a Greek or Roman deity.

18. Earth is a Heat Engine

Heat from the Sun is absorbed in low-latitude areas and at the Earth’s surface, radiating in high-latitude regions and the atmosphere. The operation of this “heat engine” is what generates winds and storms.

19. Land Subsidence is Visible from Space

Groundwater activity can cause certain effects that lead to land subsidence – and this subsidence can be observed from space.

20. The Number of Viruses Exceeds the Stars in the Sky

Earth is home to an incredible variety of viruses. It is estimated that there are more than 10³⁰ different types of viruses on our planet. This number is enough to assign 100 million to each star in the universe.