20 Interesting Facts About Earth You Might Not Know

The Earth is a bright blue marble, captivating humanity since the first moment we set foot on its surface. Earth is not just a place for humans to inhabit – it is also known as the origin of life and is the only planet that supports life. Over the centuries, we have learned a great deal about Earth – a planet that continues to intrigue us.

But how many people truly understand the Earth planet? Since our birth, we have lived on this planet, but do we really understand the ground beneath our feet? Earth – our “green home” – always harbors strange and interesting stories that not everyone knows, and below are 10 facts about Earth that you need to know.

1. Plate tectonics keep the planet “comfortable”

Earth is the only planet in the solar system with tectonic plates. Essentially, the Earth’s outer crust is divided into many parts known as “tectonic plates”. These are fragments that float on the Earth’s magma and can move toward other planets. When two plates collide, one plate is pushed back (down below another plate), and where they separate, new crust is formed.

Tectonic plates of Earth. (Source: msnucleus.org).

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

Over a long time, remnants of life, along with a large amount of carbon, are pushed back into the Earth’s interior and are recycled. This process removes carbon from the atmosphere, ensuring we do not suffer from the uncontrolled greenhouse effect that occurs on Venus, which would make Earth a “terribly” hot place.

2. Earth is nearly spherical

People have always assumed that Earth is a sphere. In fact, this idea was only accepted by science in the mid-6th century BC and in modern times. Today, thanks to modern astronomy and space travel, scientists have discovered that Earth has an oblate spheroid shape (known as an oblate spheroid).

Earth is nearly spherical, with flattened poles and a bulging equator. This bulging is caused by 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 crosses the equator of the Earth. Although the highest mountain on Earth is Mount Everest, if measured from the center of the Earth, Chimborazo in Ecuador is actually the highest.

The layers of Earth include: Inner Core, Outer Core, Mantle, and Crust. (Source: discovermagazine.com).

3. Earth is primarily composed of iron, oxygen, and silicon

When analyzing the materials that make up Earth, you will find that it consists of 32.1% iron, 30.1% oxygen, 15.1% silicon, and 13.9% magnesium. Of course, most of the iron is found 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 Earth’s surface is water

When astronauts first ventured into space and observed Earth with the naked eye, they nicknamed it 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 referred to as the “continental crust”.

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

The atmosphere of Earth is thickest within the first 50 km from the surface, but it actually extends up to 10,000 km into outer space. Earth consists of 5 main layers – the top of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. According to the laws of air pressure and density, higher air pressure means greater surface density.

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

Most of the atmosphere of Earth is located just above the Earth. In fact, 75% of the atmosphere exists 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 – up to about 10,000 km (6,200 miles) above sea level. The exosphere is the outer void of outer space, where there is no atmosphere.

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

6. Earth’s molten iron core generates a magnetic field

Earth is like a giant magnet with two poles located at either end – close to the actual geographic poles. The magnetic field extends thousands of kilometers beyond the surface of the Earth – forming an area called the “magnetosphere”. Scientists believe this magnetic field is generated by the Earth’s molten outer core – where heat creates convection currents of conductive material that generate electric currents.

Image of the magnetic field protecting Earth and the dynamo effect in the core generating the magnetic field. (Source: ESA / ATG medialab).

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

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

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

Remember that the Earth orbits the Sun. Each day, the Sun moves slightly relative to the stars in the sky by about 1⁰ – comparable to the size of the Moon in the sky. Thus, when we account for the movement from the Sun, we see that the Earth’s rotation around the Sun, in conjunction with its rotation on its axis, totals a complete cycle 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 the same position in the sky. The difference between the two is the time it takes for the stars to appear in the same spot in the sky compared to the rising and setting position of the Sun.

8. A Year on Earth is Not 365 Days

In fact, a year on Earth is approximately 365.2564 days long. The remainder of 0.2564 days results in the addition of a leap year every 4 years. This is why every four years, an extra day is added to February, as seen in the years 2004, 2008, 2012, and so forth. The exception to this rule occurs if the year is divisible by 100 (such as 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 in a co-orbital relationship with Earth? They are called 3753 Cruithne (an asteroid in the main belt orbiting the Sun) and 2002 AA29 (a near-Earth object that is about to be captured as a satellite). Most asteroids 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 as if it is trailing Earth in the same orbit, but it actually follows its own path around the Sun.

Meanwhile, 2002 AA29 is approximately 60 meters long and has a horseshoe-shaped orbit around Earth, approaching our planet only once every 95 years. It takes about 600 years to appear in the same orbit around Earth like a satellite. Scientists believe it could effectively serve as a space exploration mission.

10. Earth is the Only Planet Known to Support Life

We have found evidence of water and organic molecules on Mars and building blocks of life on the moons of Saturn. We can observe amino acids in distant cosmic nebulae. Scientists are studying whether life could 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 building laboratories to search for other planets that may harbor life. For example, NASA recently announced the creation of a scientific system for strange exoplanets called Nexus (Nexus for Exoplanet System Science – NExSS) – dedicating the coming years to studying data collected from the Kepler Space Telescope (other missions have yet to be disclosed) and signals of life on exoplanets.

Cracked and frozen 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 about intelligent life reaching out into interstellar space. New telescopes, such as NASA’s James Webb Space Telescope, the Transiting Exoplanet Survey Satellite (TESS), and the European Space Agency’s Darwin mission, may be advanced enough to detect life existing on other planets.

But interestingly, “Earth is still the only planet known to support life.”

11. The Planet Emits Radiant Energy

A 2011 study reported that Earth emits heat reaching up to 40 terawatts (TW), with half of this coming from radioactive decay in the Earth’s core. Most of the heat that supports all life on our planet comes 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 that exist at a depth of 2.5 km below the sea. Most ecosystems here develop much slower than those on the ocean’s surface. Scientists are currently searching for more traces of life that may exist deeper than previously found.

13. Moss is Everywhere

Moss is present all over our planet. Their ability to thrive arises from their unique structural characteristic – the “hairs” that grow from their leaves, allowing them to absorb water directly from the air. For moss species that live in hot and dry climates, this is indeed a very beneficial ability.

14. Earthquake ‘Weather’ is Just a ‘Myth’

“Each location will have a different type of ‘earthquake weather’ to predict when and where an earthquake will occur.” In reality, earthquakes are the result of tectonic activity happening beneath the surface of the continent, so they are unrelated to weather.

15. Clouds Help Regulate Earth’s Temperature

If we were to gather all the water in clouds and spread it over the surface of the Earth, the ground would be covered by a thin layer of water equivalent to a hair’s thickness. This “amount of water” creates the difference between summer and winter temperatures. Clouds are a crucial factor in regulating the temperature of the weather on our planet, keeping it noticeably 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 appeared around 450,000 years ago; and it was only about 45,000 years ago that humans “spread” across this planet.

17. Who Named the Earth?

Unlike other planets, where we know the origins of their names, we have no evidence to indicate “who” called this blue planet “Earth.” The term “Earth” originates from Old English and High German (a West Germanic language), 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 areas of low latitude and on the surface of the land, radiating from places of high latitude and into the atmosphere. The operation of this “heat engine” is a key factor in generating winds and storms.

19. Ground Subsidence Can Be Seen from Space

Active groundwater can cause certain effects leading to ground subsidence – and this subsidence can be observed from space.

20. There Are More Viruses Than Stars in the Sky

The Earth is home to countless types 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.