Facts About Earth

A teacher, or simply curious about our planet, you'll find a wealth of information here that is both engaging and reliable.

Earth is a dynamic planet with a rich history and complex systems. From its molten core to its diverse ecosystems, Earth is unique in the solar system. This page delves into the specifics of Earth's structure, its atmosphere, and the natural processes that shape its surface.

To get the most out of this page, start by browsing the groups of facts that interest you most.

Earth's Structure and Composition

This group covers the fundamental aspects of Earth's physical makeup, from its core to its crust.

1. Earth's inner core is primarily composed of solid iron and nickel and has a temperature of about 5,700 K, similar to the surface of the Sun.
2. The Earth's outer core is a liquid layer of iron and nickel, with a thickness of approximately 2,300 kilometers.
3. The mantle makes up about 84% of Earth's volume and consists mostly of silicate rocks rich in iron and magnesium.
4. The Earth's crust varies in thickness from about 5 kilometers under the oceans to up to 70 kilometers under the continents.
5. The Mohorovičić discontinuity, or Moho, is the boundary between the Earth's crust and the mantle, discovered in 1909 by Andrija Mohorovičić.
6. The Gutenberg discontinuity marks the boundary between the Earth's mantle and the outer core, located at a depth of about 2,900 kilometers.
7. The Lehmann discontinuity is the boundary between the Earth's inner and outer core, discovered by Inge Lehmann in 1936.
8. The Earth's crust is composed of two types: oceanic crust, which is denser and thinner, and continental crust, which is lighter and thicker.
9. The asthenosphere is a layer of the mantle that lies beneath the lithosphere, characterized by its partially molten state and plastic properties.
10. The lithosphere includes the Earth's crust and the uppermost part of the mantle, and is divided into tectonic plates.
11. The Earth's core is responsible for the planet's magnetic field, generated by the movement of liquid iron in the outer core.
12. The Earth's mantle is divided into the upper mantle, which extends to a depth of about 410 kilometers, and the lower mantle, which reaches down to the core-mantle boundary.
13. The oceanic crust is primarily composed of basalt, while the continental crust is made up of granite and other light silicate minerals.
14. The Earth's mantle is the largest layer of the planet, accounting for about 67% of its mass.
15. The Earth's crust is the thinnest layer, making up less than 1% of the planet's volume.
16. The core-mantle boundary, also known as the D'' (D double prime) layer, is a region of complex seismic activity and mineralogical changes.
17. The Earth's magnetic field is tilted at an angle of about 11 degrees relative to the planet's rotational axis.
18. The lithosphere is broken into seven major tectonic plates and several minor ones, which float on the asthenosphere.
19. The Earth's inner core is about the size of the Moon and is growing very slowly as the outer core cools and solidifies.
20. The Gutenberg discontinuity was discovered by Beno Gutenberg in 1913 through the analysis of seismic waves.
21. The asthenosphere extends from about 100 kilometers to 700 kilometers below the Earth's surface.
22. The Earth's core generates heat at a rate of about 47 terawatts, similar to the total power consumption of human civilization.
23. The Mohorovičić discontinuity varies in depth from about 5 kilometers under the oceans to up to 90 kilometers under mountain ranges.
24. The lithosphere's thickness ranges from about 15 kilometers under the oceans to up to 200 kilometers under continental cratons.

Earth's Atmosphere and Climate

Here, you'll find facts about Earth's atmosphere, including its composition and the role it plays in climate regulation.

1. Earth's atmosphere is composed of 78% nitrogen, 21% oxygen, and 1% other gases including argon and carbon dioxide.
2. The troposphere is the lowest layer of Earth's atmosphere, extending from the surface up to about 12 kilometers.
3. The stratosphere contains the ozone layer, which absorbs 97-99% of the Sun's high-frequency ultraviolet radiation.
4. Temperatures in the stratosphere increase with altitude, reaching up to about -3 degrees Celsius at its top.
5. The mesosphere is the layer where most meteors burn up upon entering Earth's atmosphere, at around 50-80 kilometers altitude.
6. Temperatures in the mesosphere decrease with height, reaching a low of about -90 degrees Celsius at its upper boundary.
7. The thermosphere extends from about 80 kilometers to 600 kilometers above Earth's surface and can reach temperatures up to 2,000 degrees Celsius.
8. The ionosphere, a region within the thermosphere, contains electrically charged particles that enable long-distance radio communication.
9. The greenhouse effect in Earth's atmosphere warms the planet's surface by about 33 degrees Celsius, making life as we know it possible.
10. The average atmospheric pressure at sea level is about 1013.25 millibars, or 1 atmosphere (atm).
11. The tropopause is the boundary between the troposphere and the stratosphere, characterized by a reversal in temperature change with altitude.
12. The stratopause marks the top of the stratosphere, where temperatures peak before decreasing in the mesosphere.
13. The mesopause is the coldest part of Earth's atmosphere, with temperatures dropping to around -90 degrees Celsius.
14. The thermopause is the boundary between the thermosphere and the exosphere, beyond which gas molecules can escape into space.
15. The auroras, or Northern and Southern Lights, occur in the thermosphere due to charged particles from the Sun interacting with atmospheric gases.
16. Earth's atmosphere scatters shorter wavelengths of light, making the sky appear blue during the day.
17. Atmospheric convection currents, driven by the uneven heating of Earth's surface, are responsible for weather patterns.
18. The Coriolis effect, caused by Earth's rotation, deflects atmospheric and oceanic currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
19. The ozone layer, located in the stratosphere, is crucial for life on Earth as it absorbs harmful ultraviolet radiation from the Sun.
20. The Van Allen radiation belts are regions of charged particles trapped by Earth's magnetic field, extending from about 1,000 to 60,000 kilometers above the surface.
21. The D layer of the ionosphere, located at 60-90 kilometers altitude, absorbs high-frequency radio waves during the day.
22. Nitrogen makes up 78% of Earth's atmosphere by volume, amounting to approximately 4 quadrillion metric tons.
23. The Kármán line, at 100 kilometers above sea level, is the boundary commonly used to define where space begins.
24. The homosphere includes the troposphere, stratosphere, and mesosphere, where gases are well-mixed by turbulence.
25. The turbopause, at about 100 kilometers altitude, marks the boundary where atmospheric mixing by turbulence ceases.
26. The average global temperature of Earth's atmosphere at the surface is approximately 15 degrees Celsius.

Natural Phenomena and Landforms

This group explores the various natural phenomena and landforms that shape Earth's surface, from mountains to oceans.

1. Earth's highest mountain, Mount Everest, stands at 8,848 meters above sea level.
2. The Mariana Trench, the deepest part of the world's oceans, plunges down to 10,994 meters.
3. The Amazon River discharges an average of 209,000 cubic meters of water per second into the Atlantic Ocean.
4. The Sahara Desert, the largest hot desert, covers an area of approximately 9.2 million square kilometers.
5. The Great Barrier Reef, the world's largest coral reef system, stretches over 2,300 kilometers off Australia's coast.
6. The Pacific Ocean is the largest and deepest ocean, covering more than 63 million square miles.
7. The Antarctic Ice Sheet contains about 70% of the world's fresh water and 90% of its ice.
8. The Atacama Desert in Chile is considered the driest non-polar desert, with some areas never receiving rain.
9. The Himalayas, the world's highest mountain range, include over 100 peaks exceeding 7,200 meters.
10. The Nile River, at about 6,650 kilometers, is traditionally considered the longest river in the world.
11. The Dead Sea, the lowest point on land, lies approximately 430 meters below sea level.
12. The Grand Canyon, carved by the Colorado River, is 446 kilometers long and up to 1,857 meters deep.
13. The Ring of Fire, a major area in the Pacific Ocean basin, is home to over 75% of the world's active and dormant volcanoes.
14. The Mid-Atlantic Ridge is an underwater mountain chain that runs over 16,000 kilometers along the ocean floor.
15. The Serengeti Plain in East Africa hosts one of the largest animal migrations, with over 1.5 million wildebeest.
16. The Appalachian Mountains, one of the oldest mountain ranges, are estimated to be over 480 million years old.
17. The Arabian Desert, covering most of the Arabian Peninsula, spans about 2.33 million square kilometers.
18. The Vredefort Crater in South Africa, the world's largest verified impact crater, has a diameter of 300 kilometers.
19. The Congo Basin, the second-largest rainforest, spans approximately 3.7 million square kilometers.
20. The Himalayas are still rising at a rate of about 5 millimeters per year due to tectonic activity.
21. The Ganges River, sacred in Hinduism, flows over 2,500 kilometers from the Himalayas to the Bay of Bengal.
22. The Kalahari Desert, covering parts of Botswana, Namibia, and South Africa, spans about 900,000 square kilometers.
23. Earth's longest mountain chain is the Mid-Oceanic Ridge, stretching over 65,000 kilometers underwater.
24. The largest known volcano in the solar system is Olympus Mons on Mars, standing at 22 kilometers high and 600 kilometers in diameter.
25. The Great Rift Valley in East Africa stretches over 6,400 kilometers, making it the longest rift on Earth.

Earth's Role in the Solar System

Discover how Earth interacts with other celestial bodies and its unique position in the solar system.

1. Earth is the only planet in our solar system not named after a mythological deity.
2. Earth's rotation is gradually slowing at a rate of about 17 milliseconds per hundred years.
3. The Moon is moving away from Earth at a rate of approximately 3.8 centimeters per year.
4. Earth's axial tilt of 23.5 degrees is responsible for the changing seasons.
5. Earth is the densest planet in the solar system, with a density of 5.51 grams per cubic centimeter.
6. The Van Allen radiation belts are two doughnut-shaped regions of charged particles surrounding Earth.
7. The point in Earth's orbit where it is closest to the Sun is called perihelion, occurring around January 3.
8. Earth's atmosphere is composed of approximately 78% nitrogen and 21% oxygen.
9. The International Space Station orbits Earth at an average altitude of about 400 kilometers.
10. Earth's gravity is slightly stronger at the poles than at the equator due to its oblate shape.
11. Earth's orbit around the Sun takes approximately 365.25 days, leading to the need for leap years.
12. The Sun's gravitational influence on Earth is about 178 times stronger than the Moon's.
13. Earth's circumference at the equator is about 40,075 kilometers.
14. Earth's lowest point, Challenger Deep in the Mariana Trench, is about 10,994 meters below sea level.
15. Earth's rotation on its axis takes approximately 23 hours, 56 minutes, and 4 seconds.
16. The gravitational force between Earth and the Moon causes tides in the oceans.

Human Impact and Environmental Facts

This group focuses on the ways humans have affected Earth and the environmental challenges we face.

1. About 8 million tons of plastic enter the oceans every year, harming marine life.
2. Over 70% of coral reefs worldwide are threatened by human activities and climate change.
3. Global wildlife populations have declined by 60% in the last 50 years due to human impact.
4. Air pollution causes an estimated 7 million premature deaths worldwide each year.
5. Humans have altered over 70% of the Earth's land surface, impacting biodiversity.
6. The Aral Sea has shrunk to about 10% of its original size due to water diversion for irrigation.
7. About 33% of global fish stocks are overfished, threatening marine ecosystems.
8. The Amazon rainforest has lost about 17% of its original area due to deforestation.
9. Urban areas cover less than 3% of Earth's land but are home to over half of its population.
10. The global average sea level has risen by about 8 inches since 1880 due to climate change.
11. About 1.3 billion tons of food are wasted globally each year, contributing to methane emissions.
12. Human activity has increased the rate of species extinction by 100 to 1000 times the natural background rate.
13. The global temperature has risen by approximately 1.2 degrees Celsius since the late 19th century.
14. About 2.2 billion people lack access to safe drinking water, largely due to pollution and climate change.
15. The world's oceans absorb about 30% of the carbon dioxide produced by human activities, leading to ocean acidification.
16. Light pollution prevents one-third of the global population from seeing the Milky Way galaxy at night.
17. About 80% of marine pollution originates from land-based activities, including agricultural runoff and plastic waste.
18. The average American generates about 4.9 pounds of waste per day, contributing to overflowing landfills and pollution.
19. Acid rain, caused by industrial emissions, has damaged forests, lakes, and buildings across North America and Europe.

How to Use These Earth Facts

To make the most of this collection, start by identifying the topics that interest you most. Whether it's Earth's core, its atmosphere, or its role in the solar system, each group is designed to provide a comprehensive overview of the subject.

For educators, these facts can be used to supplement lesson plans or to spark discussions in the classroom. For students, they offer a reliable resource for research projects and assignments.

For general readers, these facts provide an engaging way to learn more about the planet we call home. Consider starting with the group that intrigues you the most and then exploring related topics.

Why Some Earth Facts Stand Out

A fact is worth repeating if it provides concrete detail that enhances understanding. For example, knowing that Earth is the only planet in the solar system with liquid water on its surface is a compelling detail that sets it apart.

Comparisons and numbers also make facts memorable. For instance, the fact that Earth’s atmosphere is composed of 78% nitrogen and 21% oxygen is a specific detail that highlights its unique composition.

Timeless facts, such as the age of Earth or the depth of its oceans, are valuable because they provide a sense of scale and context. These are the facts that have stood the test of time and remain relevant.

How to Verify Earth Facts Before Sharing

When verifying a fact, look for sources that are known for their credibility, such as textbooks, peer-reviewed journals, and reputable science websites. Be wary of claims that lack supporting evidence or come from biased sources.

Ensure that the information you are referencing is up-to-date and comes from reliable scientific sources.

Be particularly skeptical of claims that seem too sensational or controversial. These are often the ones that drift out of date quickly or are based on misinterpretations of scientific data.

How These Earth Facts Were Selected

The facts on this page were chosen for their timelessness and reliability. They are based on well-established scientific principles and have been verified through rigorous research.

By focusing on enduring facts about Earth, we provide a resource that is both educational and enduring. These are the facts that have been proven true and will continue to be true for years to come.