One of the most surprising facts about the Earth is how we easily forget that what an amazing and interesting planet we live on. As Carl Sagan pointed out, “It’s home, it’s us”. It is the only known planet to support an atmosphere with free oxygen, liquid water on the surface, and, perhaps this is the most important amazing, life. Here are 50 interesting facts about Earth.
Interesting Facts about Earth: Space
1. Earth is a fast-moving spacecraft
We’re living in a big, fast-moving (really fast!) spacecraft. Even when you’re resting on your armchair, you’re flying through space faster than the fastest human-made object ever built: around 1.3 million miles per hour (2.1 million km/hr).
2. The first photo of Earth from space has been taken on 1946
Long before the Soviet-made Sputnik truly began the space age in 1957, on October 24, 1946, the first photo of Earth from space has been taken. The scientists launched a Nazi-built V-2 rocket (No. 13) from the White Sands Missile Range, a United States Army rocket range in southern New Mexico. There was a camera aboard the rocket, and when the rocket reached 105 km (65 mi), the black-and-white photo was taken. The rocket was one of the V-2 rockets captured and moved to the US at the end of WWII.
3. The farthest photo of Earth
The farthest spacecraft from Earth, Voyager 1, took a photo of planet Earth in 1990, from a record distance of about 6 billion kilometers (3.7 billion miles, 40 AU) from Earth. The photo is known as the Pale Blue Dot. In the photograph below, Earth is shown as a fraction of a pixel (0.12 pixel in size) against the vastness of space.
“Consider again that dot [Earth]. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor, and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.”
Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space.
4. Earth is the densest planet in our Solar System
If you’re looking for the densest planet in our solar system, you don’t have to look far: Earth is the densest planet in our Solar System. It has a density of 5.51 grams per cubic centimeter. This is only the average density of the planet. The core is much denser than the oceans for example.
5. Earth’s rotation on its Axis doesn’t take 24 hours
It actually takes approximately 23 hours, 56 minutes, and 4 seconds. This rotation is in respect to the distant “fixed” stars, and is called “sidereal day“. A sidereal day is the length of time it takes a planet to rotate from the perspective of a distant star.
Despite a sidereal day seeming pretty clear, it’s not what our calendars and clocks are based on. Because there is a nearer star whose position relative to us has a bigger effect on our lives: the sun.
So, in practice, we measure a day from noon to noon – from when the sun crosses a meridian to when the sun crosses the same meridian again. This is called “solar day”.
The Earth spins around its axis counterclockwise. It also moves around the Sun counterclockwise. After a sidereal day, the Earth moves a bit along its orbit. So some more rotation is required for the same meridian to point back towards the Sun. That’s why a “solar day”, the longer definition of one rotation, what the modern calendar and clock are based on, is 24 hours.
6. Earth is not a perfect sphere
Because of its rotation, the shape of Earth is an oblate spheroid, a sphere that is slightly squashed at its poles and slightly swollen at the equator. Despite it is not a perfect sphere, the Earth still definitely does not look like this.
7. ISS is the Most Expensive Object Ever Constructed
The International Space Station (ISS) is the most expensive object ever constructed. In 2010 the cost was expected to be $150 billion.
8. You wouldn’t explode in space without a spacesuit
It is a common myth that your body would explode in space if you don’t wear a spacesuit. Human skin is strong enough to keep the body from bursting. In fact, you can live up to two minutes in the space unprotected. But, eventually, of course, you’d die.
Also, you won’t freeze immediately in space, as in the Hollywood movies, despite its average temperature being so low (3 K, or -270 °C, -454 °F). Because there’s no matter in the space, so the heat does not leave the body quickly enough. You only lose heat via thermal radiation, of course, you will get colder and eventually freeze but very, very slowly.
There’s also a thing called Armstrong limit, often called Armstrong’s line. It is the altitude that produces an atmospheric pressure so low that water boils at the normal temperature of the human body: 37 °C (98.6 °F). The Armstrong line begins at an altitude of approximately 18 km (60,000 ft) to about 19 km (62,000 ft). It would be better to wear a spacesuit above that altitude, for your own safety (your blood’s not going to boil though, as the walls of the veins keep your blood pressure high enough to stop your blood from boiling).
At or above the Armstrong limit, exposed bodily liquids such as saliva, tears, urine, blood, and the liquids wetting the alveoli within the lungs -but not vascular blood (blood within the circulatory system), as explained before-will boil away without pressure suit, and no amount of breathable oxygen delivered by any means will sustain life for more than a few minutes.
9. Tardigrades can live 10 days in a vacuum
Speaking of surviving in the vacuum, Tardigrades, also known as water bears, can live 10 days in the vacuum, which makes them the hardest animal in existence. Two species of dried-up tardigrades were sent to space in 2007, and ten days later, they’ve been brought back, alive. They can also survive extreme conditions that would be rapidly fatal to nearly all other known life forms.
They can withstand temperature ranges from 1 K (-458 °F; -272 °C) (close to absolute zero) to about 420 K (300 °F; 150 °C), pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space. They can go without food or water for more than 30 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce.
10. The Great Wall is NOT the only human-made object visible from space
The Great Wall of China is frequently billed as the only human-made object visible from space, but it is a common misconception about Earth. Most times, it isn’t visible from the space. In fact, according to NASA, it is very difficult to see or photograph the Great Wall from even the low Earth orbit. It very rarely can be visible, and to an aided eye, under special conditions.
But, you can see a lot of things people have made, and perhaps most visible from low Earth orbit are cities at night. Cities can be seen during the day too, as can major roadways and bridges, airports, dams, and reservoirs.
11. Our satellite is big
The Earth has only one natural satellite, but it is really big: with a diameter of 2,159.2 miles (3,475 km), it is the fifth-biggest moon in the solar system. But, even more interesting, the moon is 27 percent the size of Earth, a much smaller ratio (1:4) than any other planets and their moons in our solar system.
12. The sun and the moon appear the same size in the sky
The Sun is 400 times larger than the Moon. However, it’s 400 times farther away from Earth, making them appear the same size in the sky. That’s how and why total solar eclipses occur when an observer (on Earth) passes through the shadow cast by the Moon which fully blocks (“occults”) the Sun.
13. There are a lot of human-made objects orbiting Earth
Since the launch of Sputnik 1 (4 October 1957), 38,000 artificial satellites have orbited the Earth. Still more than 22,000 human-made objects (10 cm/3.94 in or longer) up there. Only 5% of them are functioning satellites. 8% of them have spent rockets while the remaining 87% are fragments and inactive satellites (which is actually a big problem). NASA estimates every day average of 1 object is returning (falling) to Earth.
14. The Earth is 18 galactic years old
The Earth is 4.54 billion years old. Our galaxy, the Milky Way makes one rotation every 250 million years or so. As a result, our planet is approximately 18 galactic years old.
15. One can see between 2,500-4,000 stars with the naked eye in the Earth’s sky
In a clear and moonless night and far from the light-polluted areas, a young to middle-aged person with normal vision (as you get older, your eyes become much less sensitive to faint light) can see between 2,500-4,000 stars in the Earth’s sky.
16. Earth’s orbit is an ellipse
The Earth is a bit closer to the Sun in early January and farther away in July. But this elliptic orbit isn’t the reason for the Earth’s seasons, this is a common misconception. The Earth’s orbit is (and in general, planets’ orbits are) very close to a circle. This misconception is due to orbits being shown from an oblique view in most textbooks (and also in the image below) to save space.
17. Earth’s Axis is Tilted
Today, Earth’s axis is tilted 23.5 degrees from the plane of its orbit around the sun. As explained above, that’s how and why the seasons occur. This tilt changes in time. During a cycle that averages about 40,000 years, the tilt of the axis varies between 22.1 and 24.5 degrees. Because this tilt changes, the seasons as we know them can become exaggerated. More tilt means more severe seasons – warmer summers and colder winters; less tilt means less severe seasons – cooler summers and milder winters.
18. Our Moon is bigger than Pluto
Once upon a time, Pluto was a planet. Now it’s classified as a dwarf planet. With a diameter of 3,474 km (2,159 mi), our moon is bigger than Pluto, which has a diameter of 2,377 km / 1,477 mi.
Interesting Facts about Earth: Atmosphere
19. The Atmosphere of Earth Extends beyond the Moon
The Exosphere, the outermost layer of Earth’s atmosphere extends from an altitude of up to 630,000 kilometers (391,000 miles) away, or 50 times the diameter of our planet, where it merges into the solar wind. For comparison, the average distance between Earth and the Moon is 384,400 km (238,855 miles). In other words, the outer edge of Earth’s atmosphere extends far beyond the moon.
But, the atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. Three-quarters of its mass is within about 11 km (6.8 mi; 36,000 ft) of the surface (it has a total mass of about 5.15×1018 kg). The Kármán line, at 100 km (62 mi), or 1.57% of Earth’s radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi).
20. Earth’s atmosphere constantly shines
This phenomenon is known as airglow. Airglow occurs when atoms and molecules in the upper atmosphere, excited by sunlight, emit light to shed their excess energy. Or, it can happen when atoms and molecules that have been ionized by sunlight collide with and capture a free electron.
In both cases, they eject a particle of light – called a photon – in order to relax again. The phenomenon is similar to auroras, but where auroras are driven by high-energy particles originating from the solar wind, airglow is energized by ordinary, day-to-day solar radiation. And unlike auroras, airglow constantly shines.
21. Meteorites
Between 100 and 300 tons of small meteorites, mainly fragments of dust, enter the atmosphere every day. And each day, up to 4 billion meteoroids fall to Earth.
The largest known meteorite (as a single piece), and the most massive naturally-occurring piece of iron known on Earth’s surface left no crater. It’s the Hoba meteorite, which lies on the farm “Hoba West”, not far from Grootfontein, in the Otjozondjupa Region of Namibia.
Hoba is a tabloid body of metal, measuring 2.7×2.7×0.9 meters (8.9×8.9×3.0 ft). In 1920 its mass was estimated at 66 tons. Erosion, scientific sampling, and vandalism reduced its bulk over the years. The remaining mass is estimated at just over 60 tons. The meteorite is composed of about 84% iron and 16% nickel, with traces of cobalt.
The impact is thought to have occurred more recently than 80,000 years ago. The meteorite is unusual in that it is flat on both major surfaces, possibly causing it to have skipped across the top of the atmosphere like a flat stone skipping on water. Thus reducing its velocity and resulting in no crater. The meteor would have been slowed to about 720 miles per hour (0.32 km/s) from its speed on entering the Earth’s atmosphere, typically in excess of 10 km/s for similar objects.
22. Lightning strikes
Lightning strikes reach the ground on Earth as much as 8 million times per day or 100 times per second, according to the National Severe Storms Laboratory.
23. 408 km/h (220 kn ; 253 mph; 113 m/s): The fastest wind speed ever recorded on Earth
The fastest wind speed not related to tornadoes ever recorded was during the passage of Tropical Cyclone Olivia on 10 April 1996: an automatic weather station on Barrow Island, Australia, registered a maximum wind gust of 408 km/h (220 kn; 253 mph; 113 m/s).
24. Hot and cold, dry and wet
Death Valley’s Furnace Creek (a census-designated place in Inyo County, California) holds the record for the highest reliably recorded air temperature in the world, 134 °F (56.7 °C) on July 10, 1913. On the other hand, the Vostok station of Antarctica by far the coldest spot on earth, with the lowest recorded temperature at -89.2 °C (-128 °F) on July 21, 1983 (during the Antarctic winter).
It is hard to believe that the Earth’s driest place is in one of its poles, but this is the truth. It’s in Antarctica: the McMurdo Dry Valleys, which have seen no rain for nearly 2 million years.
And the wettest place on Earth is in India – according to the Guinness Book of World Records, Mawsynram received 26,000 millimeters (1,000 in) of rainfall in 1985.
Interesting Facts about Earth: Ground
25. The continents are drifting
On average, the Americas move about one inch further away from Europe and Africa per year. The landmasses move away from each other due to a phenomenon called continental drift, where the tectonic plates that continents sit on are in constant motion and can drift toward and away from one another.
26. The Himalayas are still rising, and Nanga Parbat will be the world’s highest mountain someday
The Himalayas are the product of a collision between two continental plates (India and Eurasia, because of the continental drift explained above). The collision continues today, and the Himalayas are still rising. Mount Everest, the highest mountain on Earth is rising about 4 millimeters per year on average. But, Nanga Parbat, the western-most peak of the Himalayas, the world’s ninth-highest at 8,126 meters (26,660 ft) above sea level, is growing faster than any other sizable region on Earth (at a rate of 7 mm/year).
Today, Mount Everest’s peak is 8,848 meters (29,029 ft) above sea level. With a simple calculation, after around 241,000 years from now (just a blink of an eye in the geological scale), Nanga Parbat will be the world’s highest mountain.
27. The farthest point on the Earth’s surface from the Earth’s center is not the summit of Mount Everest
Since the Earth is not a perfect sphere, the measurement from pole to pole is about 43 km (26.7 mi) less than the diameter of Earth across the equator (see #6). That title goes to Chimborazo, a currently inactive stratovolcano in the Cordillera Occidental range of the Andes. Since Mount Everest is the highest mountain by elevation above sea level, Chimborazo’s location along the equatorial bulge makes its summit the farthest point on the Earth’s surface from the Earth’s center. In a way, it is the “real” highest mountain on Earth.
28. Canada has more lakes than the rest of the world’s countries combined
Canada has an extremely large number of lakes, with the number of lakes larger than three square kilometers being estimated at close to 31,752 by the Atlas of Canada. Of these, 561 lakes have a surface area larger than 100 km2, including four of the Great Lakes. Almost 9% (891,163 square kilometers / 344,080 sq mi) of Canada’s total area is covered by freshwater. There is no official estimate of the number of smaller lakes.
29. Asia has more surface area than the Moon
Asia Continent is covered 30% of the total earth’s land area but represents 60% of the world’s population.
The continent even has more surface area than the Moon.
30. 90% of Libya is covered in desert
Libya is a predominantly desert country. Up to 90% of the land area is covered in desert.
The Libyan Desert is one of the aridest and sun-baked places on earth. In places, decades may pass without seeing any rainfall at all, and even in the highlands rainfall seldom happens, once every 5-10 years. Likewise, the temperature in the Libyan Desert can be extreme; on 13 September 1922 the town of ‘Aziziya, which is located southwest of Tripoli, recorded an air temperature of 58 °C (136.4 °F), considered to be a world record.
In September 2012, however, the world record figure of 58 °C was overturned by the World Meteorological Organization and the record went back to Furnace Creek.
31. Antarctica
Antarctica contains about 90% of the world’s ice (and thereby about 70% of the world’s freshwater). If all of this ice were melted, sea levels would rise about 60 meters (200 ft).
Antarctica is also the biggest desert on Earth.
32. Volcanoes
According to volcanodiscovery.com, the most active volcano in the world is Kīlauea (Hawaii). It is followed by Mount Etna in Italy and Piton de la Fournaise on La Réunion island.
After that, it is difficult to decide the exact order on the list, but the following are very close: Stromboli (which has erupted many times and is constantly active with minor eruptions, often visible from many points on the island and from the surrounding sea, giving rise to the island’s nickname “Lighthouse of the Mediterranean”), Merapi, Erta Ale, Ol Doinyo Lengai, Unzen, Yasur, Ambrym, Arenal, Pacaya, Klyuchevsky, Sheveluch, and Erebus.
But what is an active volcano? The Smithsonian Global Volcanism Program defines an active volcano as having erupted within the last 10,000 years. There are approximately 500 active volcanoes in the world today, not including those underneath the oceans.
A volcano finally goes extinct when there’s no lava supply in the magma chamber beneath the volcano.
Interesting Facts about Earth: the Seas
33. The oceans cover 71% of the Earth’s surface
And that percentage is growing, because of global warming. If sea level should rise by 3 meters (10 feet), many of the World’s coastal cities, like Venice, London, New Orleans, and New York, would be underwater.
34. The Pacific is big
The Pacific Ocean is by far Earth’s largest ocean basin, covering an area of about 59 million square miles (155 million square kilometers) and containing more than half of the free water on Earth, according to NOAA (National Oceanic and Atmospheric Administration). It’s so big that all of the world’s continents could fit into it.
35. All Earth’s water can fit in a sphere 860 miles (1384.04 km) in diameter
Yes, the Pacific is big, and 71% of the Earth’s surface is covered by oceans – but despite that, all Earth’s water, liquid freshwater, and water in lakes and rivers can fit into a sphere 860 miles (1384.04 km) in diameter.
36. The largest ocean in the Solar System is probably not on Earth
Jupiter’s moon Europa is just a bit smaller than our Earth’s moon, which may have a worldwide ocean 100 kilometers (60 miles) deep covered with ice. Such an ocean might contain more liquid water than all the Earth’s oceans combined!
