The Earth’s crust is the hard layer of the Earth. All humans, plants, and animals live somewhere along the outermost layer of the Earth’s crust. Despite being hard and dense, unlike the crust of a pizza, the crust makes up only about 1 percent of our planet’s volume. In this article, we’re going to talk about some of the most interesting facts about the Earth’s crust.
1. Hot but cold
The Earth’s crust, at its deepest points, can reach temperatures of up to 752 degrees Fahrenheit. To put this in perspective, most stone pizza ovens can only reach a temperature of around 500 degrees Fahrenheit. Even though it’s super hot by human standards, it’s also the coldest part of our planet. Earth’s core, the very center of our planet, can reach up to 10,800 degrees Fahrenheit, about the same temperature as the surface of the sun.
2. Thickest parts of the crust are under mountains
The deepest parts of the Earth’s crust can be found right below mountains. “Roots” found under mountains connect the natural stone structures to the unseen layers of the Earth. Surprisingly, the roots of the mountains are less dense than the mountains so they can actually float when placed on water. These mountain roots can reach up to 43 miles into the Earth.
3. Plate Tectonics
This theory states that the Earth’s outer crust is divided into 15 major plates which are constantly at motion. We know that these plates move thanks to satellite imagery that records the slow process over a period of many years. Originally, the entire land surface of the Earth was one large continent called Pangaea. Over the course of billions of years, the plates moved outwards, thus splitting up the continents to what we have today.
4. Composition of the Earth’s crust
Earth’s crust is made of several chemical elements, the most abundant of which is oxygen. The gas makes up around 46% of the crust while the different metals and rocks make up the rest. This, however, doesn’t mean that inhaling the crust – if even possible – is safe to do. This does mean that there are tremendous amounts of previous rocks and minerals hiding just below the surface in the unreachable depths of the crust and lithosphere. The bad thing is that it would cost mining companies considerably more to dig up the precious materials from the lithosphere than the cost of selling the materials at current market value.
5. Creation process
The crust was formed during the rapid and drastic heating and cooling of the Earth over the course of millions of years while our planet was newly formed. Because of the drastic changes in temperature, the crust and mantle, though located on top of one another, are composed of different materials.
6. Average age of the crust
The Earth is about 4.7-billion-years-old. The conventional belief is that the crust is only about half as old as the Earth. However, studies have confirmed that the crust is about as old as the planet it covers. This was done by observing how atoms pass through zircon.
7. The Moon is partly made up of the Earth’s crust
There is a widely believed theory that suggests that the Moon is made of the some of the same materials as the Earth’s crust. This is because, as the theory states, that when Earth was still a little planet, a protoplanet smashed into the Earth, causing a large chunk of Earth to break off. The chunk, however, was kept from straying too far due to the Earth’s gravitational pull.
8. Living organisms in the Earth’s crust
Despite there being a lack of sunlight, small organisms have been found to be living deep within the crust of our planet. These fungus-like organisms have never made contact with surface dwellers. It’s pretty scary to imagine something embedded so deeply into the Earth without being noticed for so long.
9. Crust is extremely thin
Continental crust is about 20 miles deep while oceanic crust is about 6 miles thick. Even though we’ve never been able to dig deep enough to penetrate the crust, it’s actually an extremely thin layer covering our planet. To put this in perspective, if the Earth were shrunk down to the size of an apple, the crust would be thinner than the skin of an apple.
10. Earth isn’t the only planet with a crust
We know that on the crust of our planet, humans, plants, and animals live. However, this doesn’t mean that Earth is the only planet with a crust. Mercury and Venus have inner cores and mantles that are also covered with an outer layer of hard rocks and metals. Gas giants like Saturn, Jupiter, Uranus, and Neptune lack a thick, outer layer of rock for us to stand on. In fact, Saturn, if placed in a plate of water, would float.
11. There are places on Earth not covered by the crust
Normally, the crust covers the lithosphere – a layer in between the hot mantle and the cool crust. However, there are many places on Earth such as the Indian Ocean and Marion’s Rise that aren’t protected by a crust. This means that if you were to venture underwater, you would like directly at the Earth’s outer mantle.
12. Deepest mine in the world
The Mponeng gold mine located in Johannesburg, South Africa, is the deepest mine on the planet. It reaches between 2.5 and 3.9 kilometers below the surface of the Earth. However, this is only a fraction of the Earth’s crust, and diggers still have many, many more kilometers to dig before reaching the lithosphere.
13. You can thank underground activity for volcano eruptions and earthquakes
Tectonic plates are constantly in motion, moving toward and away from each other. This causes weak points in the Earth’s crust which allows magma to rise and erupt through volcanoes. Earthquakes occur when underground rocks crack along a fault. The sudden release of high energy sends seismic waves that cause the ground to shake. This happens when two tectonic plates rub up against each other and break at a meeting point between the two plates.