Earth Facts

Tadashi

Tadashi

31 Mar 2020

earth facts

Humans have always lived on the Earth. In that time, they’ve discovered plenty of its wonders and secrets, though many more still wait to be revealed. From what’s already been discovered, here are essential Earth Facts to help you understand our planet better.

  1. Earth has a radius of 6,371 km.
  2. Earth is the third planet from the Sun.
  3. The distance between Earth and the Sun extends 149.6 million km.
  4. Earth weighs about 5.972 × 10^24 kg.
  5. Earth’s surface has an area of 510.1 million km².
  1. Earth is approximately 4.54 billion years old.
  2. Earth’s first-known supercontinent, Rodinia, lasted from 1.1 billion to 750 million years ago.
  3. The current Phanerozoic Eon began 541 million years ago.
  4. History’s first mass extinction, the Ordovician-Silurian, took place between 450 and 440 million years ago.
  5. The supercontinent Pangaea formed approximately 335 million years ago.
  6. Dinosaurs ruled the Earth from 251.9 to 66 million years ago.
  7. The modern Ice Ages first began 40 million years ago.
  8. The Ice Ages increased in occurrence starting 2.6 million years ago.
  9. Earth’s continents reached their modern positions in the Pleistocene Epoch.
  10. Modern Humans also evolved in the Pleistocene Epoch.
  1. The Old Faithful Geyser is likely to stop erupting in the next 1000 years.
  2. Current trends predict the next Ice Age in about 100,000 years.
  3. Scientists predict a new supercontinent, Pangaea Ultima, to form in the next 300 million years.
  4. Volcanic activity increases when all continents merge into a supercontinent.
  5. There is a less than 1% chance of Earth colliding with another planet in the Solar System.
Table of Contents

Earth Facts Infographics

Earth Facts Infographics

Earth formed during the Hadean Eon.

The Hadean Eon lasted for approximately 600 million years, for 4.6 billion to 4 billion years ago. Scientists think that the Earth formed from dust clumping together in a cloud of gas and dust around the young Sun. Earth at this time was a volcanic world, with many volcanoes erupting at the same time. Asteroid impacts were also very common at this time. The hellish conditions of the young Earth are why this period of time has the name Hadean Eon, from Hades, the Greek god of the underworld. Talk about a fiery beginning as far as Earth Facts are concerned.

hadean eon, earth facts
Photo by PublicDomainPictures from Wikipedia

Earth’s water came from various sources.

The biggest source was water vapor in the eruption clouds of early Earth’s volcanoes. Water vapor was also in the gases slowly pouring out of dormant volcanoes and other geological formations on early Earth. Comets impacting the planet added more water. As the planet cooled, water vapor turned liquid and rained down on the surface. Over hundreds of millions of years, the liquid water gathered and grew, forming pools, lakes, rivers, seas, and finally the oceans.

An impact with another planetary body formed the Moon around 4.5 billion years ago.

Scientists theorize that the Moon formed when a smaller body called Theia slammed into the Earth 4.5 billion years ago. This threw large amounts of debris into the surrounding space, while Theia’s core sank into and merged with Earth’s core. Over billions of years, the debris surrounding the Earth clumped together into a single body, orbiting the Earth. That orbiting body is what we know today as our Moon.

The first life on Earth also appeared during the Hadean Eon.

Scientists based this on microfossils dating back to around 4.3 billion years ago. These microfossils indicate the first life forms are similar to deep-sea bacteria that grow around hydrothermal vents. The surrounding water protected them from extreme temperatures and radiation if cutting them off from sunlight. Without sunlight for photosynthesis, these ancient life forms instead fed on the chemicals belched out by the hydrothermal vents. An adaptable example of Earth Facts, to be sure.

Life on Earth first appeared about 3.5 billion years ago.

Scientists determined this in 2017, following the discovery of bacterial microfossils in geyserite samples. Like their underwater cousins, these bacteria depended on chemicals from geologically-active water formations like geysers and hot springs to survive.

The magnetic field around Earth first appeared during the Archean Eon.

Interactions between Earth’s inner and outer cores generate a magnetic field around the planet. This magnetic field is what allows a compass to point which way is north or south. It also protects the planet from the Solar Wind, a stream of energy from the Sun that could blow our atmosphere away. The generation of the magnetic field began around 3.5 billion years ago, as the heavy elements of iron and nickel settled in the center of the Earth. At the time though, it was only half as strong as it is today but grew stronger over billions of years.

Earth’s magnetic field does not provide complete protection.

northern lights, earth facts
Photo by ISS Expedition 23 crew from Wikipedia

It may seem like it, but this isn’t one of the worrying Earth Facts. When the Sun is especially active, small amounts of high-energy particles slip through gaps in Earth’s magnetic field. These then strike against the ionosphere, the upper layer of Earth’s atmosphere. Interactions between those particles and our atmosphere generate energy bursts, appearing as lights in the sky. These usually appear in northern and southern latitudes, aurora borealis, the northern and southern lights.

The first photosynthetic life forms appeared 2.7 billion years ago.

Scientists think these life forms were single-cell bacteria in the early oceans. They used sunlight to help break down carbon dioxide into oxygen and to power other biochemical processes. Oxygen is a waste gas for photosynthetic life forms, and it’s released into the surroundings. At the time, free oxygen on the early Earth was rare, but as photosynthesis grew more common, free oxygen rose over time.

The Oxygen Crisis took place over 2 billion years ago.

Today we’re so used to breathing oxygen and knowing it as essential for life, that we forget its other properties. Oxygen is a very active element and reacts easily with other elements. In fact, it’s from oxygen that the term oxidation comes from. Billions of years ago, rising oxygen levels produced by photosynthesis proved devastating to early life forms. Scientists estimate that this period lasted over 400 million years, from 2.4 to 2 billion years ago.

Since they evolved from an oxygen-poor environment, the rising oxygen levels either suffocated or destroyed them outright. Those that survived evolved complex cellular repair mechanisms to handle oxygen’s reactive properties. Scientists theorize that this opened the door for the evolution of multicellular life. There’s an interesting example of Earth facts.

The Cambrian Explosion happened 541 million years ago.

The Cambrian Explosion is one of the most important events in the history of life on Earth. Before the explosion, the most complex life on Earth was sheet-like colonies of single-celled life. During the explosion, multicellular life flourished, with all plant and animal phyla evolving at this time. The reason for this explosion of life is still under study at this time.

Five mass extinctions have taken place in Earth’s history.

The first of those was the Ordovician-Silurian Extinction Event, between 450 and 440 million years ago. It was also the second-largest of the five, killing between 60 to 70% of all life on Earth. The Late Devonian Extinction Event followed, between 375 to 360 million years ago.

The Permian Extinction Event followed 252 million years ago, with the Triassic Extinction Event 201 million years ago. The last of the five mass extinctions is the Cretaceous Extinction Event, taking place 66 million years ago. Definitely one of the grim Earth facts.

The Permian Extinction Event is also called the Great Dying.

Trilobite fossils, of the kind which went extinct during the Great Dying.
Photo by Moussa Direct Ltd. from Wikipedia

One of the more surprising Earth facts: the Permian Extinction Event once killed 90%-96% of all life at the time. MAny have theorized its cause, including asteroids or comet impact. Another likely theory is a mass volcanic event towards the end of the Permian Period, in what is now called the Siberian Traps. The event covered over 2 million km² of surface area in lava, but that was not what made it deadly.

Scientists instead say the event released large amounts of carbon dioxide into the atmosphere, while lava flowing into shallow seas melted ice crystals that locked methane gas inside. In addition to enhancing the Greenhouse Effect, large amounts of methane entering the seas and oceans caused what’s called anoxia. This is when the seas and oceans have low oxygen levels, made worse by lava introducing sulfur dioxide into the water. This suffocated water-based life and encouraged the growth of poisonous sulfur bacteria. 

The Cretaceous Extinction Event wiped out the dinosaurs.

Including the dinosaurs, 75% of all life on Earth died during this mass extinction. Scientists are now all but completely certain the mass extinction resulted from an asteroid impact. Scientists base this on geological evidence recovered from the Chicxulub Crater buried under Mexico’s Yucatan Peninsula. The asteroid measured between 10 to 15 km in length and left a crater 180 km across. The mass extinction did have beneficial effects, though. By removing competition from the then-dominant species, mammalian life gained the opportunity to become dominant on the planet.

Scientists argue that humanity is the cause of ongoing mass extinction.

This theorized ongoing mass extinction is the Holocene Extinction Event. Scientists set its start in 1900, at the beginning of the 20th century. This is because starting in the 20th century, extinctions of species worldwide rose by an estimated 1000% thanks to human activity. Other scientists argue the event goes back to the last Ice Age when early humans hunted large mammals like the mammoth to extinction. They even go so far as to label humans as a global superpredator.

Critics argue that while the evolution of man has caused plenty of extinctions, it has not reached the percentages of past mass extinctions. However, they admit that humanity is well on its way. Definitely one of the Earth facts that put things in perspective.

Earth’s core has two layers.

They’re the inner and outer core. The inner core is pure iron, kept solid by the immense pressure at its depth. If not for the pressure, the iron should turn to gas, as iron’s boiling point is only 2,862°C. The inner core’s temperature though is 6,000°C, equal to the surface of the Sun. The outer core though is molten metal, of iron and nickel. As the metal cools, it sinks to the bottom of the core, and heating up, rises once more. This sinking and rising of molten metal are what generates Earth’s magnetic field.

Earth’s magnetic field is weakening.

This is because as time passes, the iron inside the outer core solidifies on the surface of the inner core. As iron gets deposited, the inner core grows, while the outer core shrinks. As it shrinks, less molten metal moves around, weakening the magnetic field. Once the outer core disappears, so too will the magnetic field. Scientists though say this won’t happen for another 3 to 4 billion years. Now, there’s an example of Earth facts that isn’t as worrying as it sounds.

The North and South poles sometimes switch places.

Every so often, the Earth undergoes a geomagnetic reversal where the north and south poles switch places. According to scientists, reversals happen at random intervals, with 183 reversals taking place over the last 83 million years. They are also slow, taking place between 2,000 to 20,000 years. And despite what popular fiction says, magnetic reversals do not cause mass extinctions. Definitely one of the Earth facts that’ll turn your world upside down.

The Sun’s aging will have a heavy effect on life on Earth.

As the Sun grows older, it’ll go brighter and bigger. About 600 million years from now, the amount of sunlight will break down carbon dioxide in the air to the point that there won’t be enough to photosynthesize. This will then cause plant life to decline, which causes animal life to decline. The Sun’s increased heat will also force life to migrate to cooler regions near the poles, or even underground. As Earth’s environment grows more extreme from solar radiation, scientists expect multicellular life to go extinct 800 million years from now. There’s one for Earth facts that prove nothing lasts forever.

Earth’s oceans will disappear 1.1 billion years in the future.

As the Sun grows brighter and bigger with age, Earth will grow hotter as a result. Scientists predict that 1.1 billion years from now, Earth’s surface temperature will average 47°C. This, in turn, triggers a runaway Greenhouse Effect with Earth’s oceans evaporating at a steady rate. Once in the atmosphere, the water vapor breaks down thanks to high-energy UV radiation. As the oceans disappear, even single-celled life will finally go extinct. A solemn but inevitable example of Earth Facts, no doubt about it.

bacteria, earth facts
Photo by CSIRO from Wikipedia

Earth could get destroyed by an old Sun.

Once the Sun reaches the age of 12 billion years, it’s expected to swell into a Red Giant. In this state, it’ll blow away Earth’s atmosphere, and turn the surface into a sea of molten rock. The closeness to the Sun will also affect the Moon’s orbit, causing it to grow closer to the Earth and break up into a ring of debris. This debris will then rain down on the Earth. As the Sun continues to age, it’ll blow off its outer layers, the hot gas stripping away Earth’s matter until only the core gets left behind. Scientists predict that the exposed core will either get pulled into the Sun or blown away as well.

If Earth isn’t destroyed by an old Sun, it’ll either get thrown out of the Solar System or crash into it.

Once the Sun dies, it’ll turn into a Black Dwarf, a chunk of black diamond in space. In this state, any surviving planets including the Earth will get thrown out of the Solar System as their orbits collapse. If not, then they’ll crash into the Sun’s cinder as their orbits still collapse. A solemn reminder of sorts from Earth Facts, on how all thing must come to an end sooner or later.

Earth once went through an extreme Ice Age.

During the extreme Ice Age, the Earth completely froze with ice sheets present even at the equator. Study shows that this became possible due to continents moving towards low or middle latitudes. This reduced the amount of solar light and heat reaching the oceans while allowing more rainwater to fall on the land.

These conditions allowed more biochemical reactions that reduced carbon dioxide in the atmosphere and weakened the Greenhouse Effect. The Snowball Earth ended after volcanoes released enough carbon dioxide into the air to strengthen the Greenhouse Effect to normal. The last time Earth entered a snowball state was before the Cambrian Period. Scientists also say that Earth’s snowball state contributed to the Cambrian Explosion.

The opposite of a Snowball Earth is a Hothouse Earth.

During a Hothouse Earth, there will be no glaciers anywhere on the planet, while temperatures at the poles go no lower than 0°C. At the equator, the lowest the temperature goes is 28°C.

The Earth has been in a Hothouse state for 80% of the past 500 million years. However, urbanization and industrialization now seems to push the Earth back into a hothouse state. Human civilization’s large contribution of greenhouse gases into the atmosphere drives the Greenhouse Effect into overdrive.

The Greenhouse Effect is natural.

Without the Greenhouse Effect, then Earth’s temperature averages at -18°C. Life needs the Greenhouse Effect in order to exist. It works when certain gases keep heat in the atmosphere instead of radiating or reflecting it back to space. Those gases include water vapor, carbon dioxide, and methane. The Greenhouse Effect only becomes a problem when it becomes excessive, like what’s happening today because of global warming.

Earth can’t become like Venus.

We’ve previously mentioned that human civilization could force Earth to enter a hothouse state. However, it won’t be as bad as Venus. Venus is so hot lead flows like water on its surface. There aren’t any oceans or liquid water of any kind. But the important part is that no matter how we humans make it, Earth can’t become like Venus. That needs all of Earth’s oceans to evaporate into the atmosphere, and we humans aren’t able to do that. And while nature is able to, it’d take hundreds of millions of years and conditions that don’t exist to do so.

venus, earth facts
Photo by NASA from Wikipedia

Earth’s mantle isn’t molten.

Despite what popular fiction tells you, Earth’s mantle isn’t made of molten rock. It’s actually solid, but that doesn’t mean the heat and pressure in its depths have no effects. They actually make the solid rock behave like its plastic, deforming and stretching over time. There are pockets of molten rock though, where heat from the core or radioactive elements in the mantle becomes too much. Places where one continent sinks under another also get hot enough to melt rock. It’s these places that fuel volcanic activities on the surface.

Earth’s crust has cracked into plates.

These plates then float on a thin layer of molten rock called the asthenosphere. Interactions between the plates and the asthenosphere drive continental drift, the movement of the continents over millions of years. The shifting of the plastic-like rock of the mantle is also a factor in continental drift. That most of Earth’s surface is also covered by water is a factor, with scientists saying that ocean water acts as a lubricant for continental drift.

The movement of the plates causes earthquakes.

One example of this is at the San Andreas Fault in California.  There, the Pacific and North American plates grind against each other, and it’s that grinding that causes the devastating earthquakes of the region.

Plates grind together in three ways.

Tectonic plates grind together in different ways. The most common way is them sliding against each other in the opposite direction (transform). But plates also move vertically, with one side of the fault rising above the other (divergent), or sinking below the other (convergent).

Earthquakes cause tsunamis.

Imagine you have a bucket full of water, and you shake it. What happens? It sloshes around in waves, right? That’s what happens when an earthquake strikes near the sea. But they don’t only cause tsunamis, they can make them stronger too. They do that by breaking parts of the land, which then fall into the sea. Imagine shaking the bucket you imagined earlier and dropping a rock into it at the same time. In addition to the waves, you get a big splash. The same idea applies to earthquakes and tsunamis.

tsunami warning, earth facts
Photo by Mimigu from Wikipedia

Earthquakes aren’t the only cause behind tsunamis.

Another cause for tsunamis is underwater collapses. This is when underwater geological formations collapse for one reason or another. As they fall apart, they churn up the water around them. They could also open up spaces underground, which the sea then rushes in to fill. These can all se a tsunami.

The 2004 Indian Ocean Tsunami was the worst in human history.

The tsunami resulted from a magnitude 9 earthquake under the sea off the west coast of Sumatra, Indonesia. The tsunami’s waves reached a maximum height of 30 meters and affected 14 countries. The worst-hit of those countries were India, Burma, Thailand, and Indonesia itself. 227,898 people died, while the cost of the damage comes to $15 billion.

The most powerful earthquakes are more powerful than nuclear weapons.

The strongest earthquakes pack more of a punch than the nuclear weapons used against Japan in WWII. Each of those weapons exploded with the force of 20,000 tons of TNT. For example, there’s the 2010 Chile Earthquake, with a magnitude of 8.8 and killed over 500 people.

According to scientists, the power of the earthquake surpassed 10,000 nuclear weapons of the kind used in WWII. To give a number, the earthquake had more power than 200 million tons of TNT exploding at the same time.

The 1960 Valdivia Earthquake was the worst earthquake in human history.

The earthquake measured a magnitude of 9.5 and killed between 1000-7000 in Valdivia, Chile. Exact numbers are hard to get because of the damage. The earthquake also set off a tsunami, which devastated the Pacific Rim. Affected places include Hawaii, the Philippines, Alaska, Japan, and even Australia and New Zealand. The amount of damage the quake and tsunami both caused amounts to between $3.5 to 6.9 billion.

Mountains rise thanks to plate tectonics.

There are two ways this can happen. One is when two continents slam into each other and form mountains from the crumpling of their plates. An example of this is the Himalayas, where the Indian Plate is slamming into the Eurasian Plate. The second way is when one plate sinks under another, and melting, erupts upwards in the form of volcanoes. The Andes Mountains of South America and other volcanic mountains along the Pacific Rim of Fire result from this. Talk about an earthshaking example of Earth facts.

mount everest, earth facts
Photo by Papa Lima Whiskey 2 from Wikipedia

Volcanoes die when they move away from hotspots.

A hotspot refers to molten rock from a pocket in the mantle erupts towards the surface. An example of this is in the Hawaiian Islands. But while the continental plates move, the hotspot stays where it is. As the volcanic mountain or island moves with the plates, they’re cut off from the hotspot and die. The hotspot continues to erupt though and builds another mountain or island above it.

Growing continental plates causes volcanic eruptions as well.

You can see this in the Mid-Atlantic Ridge, deep beneath the middle of the Atlantic Ocean. Here, lava flows up along the edges between four plates, and adds more matter to them and builds new mountains. To the north, the plates are the Eurasian and North American Plates.

To the south, they are the African and South American Plates. Most of the mountains built by the lava flowing from between the plates are underwater, where they form the longest mountain range in the world. One example that’s above the water is Iceland, in the North Atlantic.

Scientists have evidence to confirm 60 supervolcanic eruptions in Earth’s history.

A supervolcanic eruption is one that erupts more than 1000 km³ worth of volcanic material. To provide context, the largest volcanic eruption in human history, the Tambora Eruption of 1815, is not a supervolcanic eruption.

The Siberian Traps eruption around 250 million years ago is the most likely theory behind the extinction of 90% of all life on Earth at the time. The most recent supervolcanic eruption is the Oruanui Eruption around 26,500 years ago in  New Zealand. Lake Taupo now fills part of the volcano’s crater.

Tambora’s eruption in 1815 was the worst in human history.

This doesn’t count supervolcanic eruptions, but none of those have erupted in human history so far. Tambora’s eruption in 1815 was so powerful that it didn’t only affect the surrounding Indonesian islands. All the ash and sulfur dioxide it put in the air reflected so much heat and light from the Sun that they caused a drop of between 0.4°C to 0.7°C.

This persisted for the next ten years, and in particular caused 1816 to become the Year Without a Summer. Freezing temperatures persisted through what should have been spring and summer, ruining harvests across the world. In the tropics, the monsoon lasted longer, setting off floods destroying homes and crops. Scientists studying this effect in the present call it a volcanic winter. Yet another grim example of Earth Facts.

There’s no real difference between typhoons and hurricanes.

The only difference is where they come from. Hurricanes are storms spawning in the North Atlantic and Northeastern Pacific Oceans. If it comes from anywhere else, they’re called typhoons.

hurricane isabel, earth facts
Photo by Mike Trenchard from Wikipedia

Warm seas and low atmospheric pressures are the basic conditions to spawn a storm.

Other conditions include high humidity and low vertical wind shear. The latter is actually quite important, as a strong wind blowing upwards could actually blow a storm apart. In a storm, the wind blows sideways and in a circle, not upwards. The warm seas provide the energy to form the storm, while the low pressure forms a core into which higher pressure air gets pulled into.

Typhoon Tip in 1979 was the most powerful storm in history.

It’s also called Typhoon Warling in the Philippines, the first country it devastated. From there it moved north, striking southern Japan before dissipating. At its strongest, the typhoon had a maximum wind speed of 305 km/h. It also set a record for the largest storm in history, with the cyclone reaching a diameter of 2,220 km. 99 people died because of the storm, which also inflicted millions of dollars worth of damage.

Rainforests have a climate of their own.

The rainforest climate is a variation of tropical climate, but with no dry season. Instead, rainforests enjoy rain all year round, with at least 1,750 mm of rain per year. Average temperatures also drop no lower than 18°C. They also have similarities with oceanic climates, with plentiful rain all year round. The difference is that oceanic climates are usually enjoyed along coastal areas next to the sea.

The monsoon climate is what’s commonly seen as the tropical climate.

These climates have 2 seasons, dry and wet. The most rain falls in the wet season, but it’s not unknown for the rain to fall at times during the dry season. Like rainforests, monsoon climates usually have at least 1,750 mm of rain per year, and average temperatures of no less than 18°C.

Tropical savannahs are an unusual variation of a tropical climate.

They’re still tropical thanks to having the 2 seasons characteristic of tropical climates. Average temperatures also drop no lower than 18°C. They’re unusual in the sense that they enjoy less rainfall compared to other tropical climates. On average, tropical savannahs enjoy only between 750 mm and 1,270 mm of rain per year.

tropical savannah, earth facts
Photo by Geoff Gallice from Wikipedia

Subtropical climates have 4 seasons like temperate climates.

They’re considered subtropical because of their similarity to tropical climates, in the sense that rainfall is usually in one season. In their case, it’s winter. Also, their latitudes are such that rain and storms are more common than snow, though it’s not unknown either. A particular subtype of this is the Mediterranean, with the added difference of having a particularly-hot summer.

Continental climates are the classic temperate type.

Continental climates have 4 seasons through the year: spring, summer, autumn, and winter. Temperatures and rainfall avoid reaching any extremes, which is why they’re also called temperate. Outside of winter, average temperatures don’t drop below 10°C. In winter, temperatures usually only go as high as -3°C, but this is only at their coldest, and most of the winter season doesn’t get as cold.

Steppes are a subtype of the arid climate.

They enjoy enough rain to support large amounts of grass, but not enough for bigger plantlife. Temperatures also reach extremes in the steppe, going as high as 40°C in summer. In winter, temperatures reach similar extremes but in the opposite direction, at -40°C.

Deserts are the other subtype of the arid climate.

Deserts have the characteristic of not having any rain at all, or even if there is, it’s very rare. Temperatures reach even greater extremes in deserts, at least when it comes to heat, at up to 45°C in the daytime. At night though, deserts usually only reach down to 0°C.

Subarctic climates are another subtype of temperate.

They too have 4 seasons but have very low rainfall. Temperatures also only go above an average of 10°C for 1-3 months a year. Temperatures never go above 0°C in the winter, and even outside of the winter, the subsoil remains frozen. This phenomenon is what’s called the permafrost.

subarctic climate, earth facts
Photo by Chmee2 from Wikipedia

The tundra exists between subarctic and arctic climates.

Tundras only enjoy 2 seasons, summer and winter. In summer, temperatures never rise above 12°C, while the subsoil is always frozen. Between the low temperatures and the permafrost, trees don’t grow in the tundra. In winter, temperatures reach extremes of cold, as low as 50°C.

Arctic and polar climates are one and the same.

Arctic and polar climates are both characterized by a surface covered in ice sheets and temperatures never rising above 0°C. The latter makes the former possible, while the former helps maintain the latter. Specifically-speaking, the ice reflects light and heat from the Sun back to space, helping keep temperatures down.

Earth’s the only planet in the Solar System not named after a god.

Every other planet has a name from one of the Roman gods, like Mars the god of war, or Venus, the goddess of love. Even little Pluto’s name comes from the Roman god of the underworld. Earth, in contrast, takes its name from Middle and Old English words for the land and the soil.

Scientists took the first picture of the Earth from space on October 24, 1946.

Scientists took a captured German V2 rocket and replaced its bomb with scientific equipment. One of those was a 35 mm camera, which took the first-ever picture of Earth from space. It was black and white and had poor resolution, but it was still a historic moment.

The pale blue dot is one of the most iconic pictures taken of the Earth.

The space probe Voyager 1 took the photo from a distance of 6 billion km away, at the very edge of the Solar System itself. In the photo, Earth appears as only a pale blue dot the size of a needle’s head. This is, in fact, the origin of the photo’s name. For academics, scientists, and activists, it underlined how fragile the Earth was, and how it was also the only home Humanity had in the universe. How’s that for Earth facts?

pale blue dot, earth facts
Photo by NASA/JPL-Caltech from Wikipedia

People used to think the Earth was the center of the cosmos.

Named after Claudius Ptolemy, the Ptolemaic Model proposed the Earth as the center of the universe. He developed the idea based on observations of how the stars moved across the sky during the seasons and concluded it was because they moved around the Earth.

This model of the universe was later supported by the Church, as it fits with their teachings of how God made Man as the center of the universe and Earth as their home. It wasn’t until Galileo and Copernicus used additional observations in the 16th century that people realized that Earth wasn’t the center of the universe.

People didn’t think the Earth was flat in ancient times.

Despite what popular fiction or conspiracy theories say, the ancients knew the Earth was round. They noticed this from observations on how ships slowly disappeared below the horizon as they sailed into the distance. The mathematician Eratosthenes even calculated Earth’s circumference with an error of only 15% during the 1st century BC.

Scholars preserved this knowledge even after the Fall of the Roman Empire, and while it took Magellan’s expedition to prove it, academics even at the time already knew the Earth was round. Definitely one of the Earth facts to remember.

Earth is the densest planet in the Solar System.

Earth is the largest rocky planet in the Solar System. Jupiter and the other gas giants are larger, but more than 90% of their mass is in the form of gas. Its density is 1.33 g/cm³, in contrast to Earth’s, which is 5.51 g/cm³.

Despite the fact that Jupiter has a radius of 69,911 km compared to Earth’s 6,371 km, Jupiter is far less dense than the Earth. The only planet which comes close to Earth’s density is Mercury, at 5.43 g/cm³. How’s that for cool Earth facts?

Earth’s tilted on its axis.

Scientists theorize this tilt is also a result of the ancient impact which also produced the Moon. This tilt angles the Earth 23° away from the Sun, ensuring different parts of the planet receive different amounts of light and heat. Together with its rotation around its axis, this is what leads to the seasons.

The Earth is slowing down.

This is a side-effect of the Moon orbiting the Earth. The Moon’s gravity pulls on the Earth and causes it to slow down. This is very slight though, Earth losing only 17 mm for every 100 years. At that rate, it will take another 140 million years before a day on Earth grows from 24 hours to 25 hours.

moon, earth facts
Photo by Gregory H. Revera from Wikipedia
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