Facts about Animal

Facts about earth,s parts 3

21. One full rotation takes 24 hours

A full day on Earth is clocked at 23h 56 min 4sec. In order to make a complete rotation in this amount of time, Earth travels at 1000 miles per hour (1600 km/hr).

That makes Earth’s rotation faster than a bullet train but not a speeding bullet. But our bodies are so used if to it that we don’t feel its speed. Earth’s rotation is a pace-setter for our sleep patterns.

If you shine a flashlight on a spinning top, the side lit up is daytime. The dark side is night-time. That’s how our day-night cycles work with the sun as our flashlight.

22. Earth is not a perfect sphere

Earth is an oblate spheroid shape. But it’s nowhere close to being flat.

As the Earth spins on its axis, it flattens at the poles and widens at the equator. Sir Isaac Newton proposed that the centrifugal force causes the planet to bulge at the equator and somewhat squash at the poles.

This is why geographers model the Earth as an ellipsoid, which is a sphere slightly flattened at the poles.

23. Ocean tides and the moon

It’s not only rotation that causes Earth to flatten at the poles, but it’s also from the moon’s gravitational pull. Because the moon is close to the Earth, it stretches the planet where it’s facing.

When the Earth rotates, the bulge shifts on both sides of the planet according to the position of the moon. In full swing, this causes sea levels to rise and fall which are ocean tides.

The sun has a lesser effect than the moon. Even though the moon is smaller, the moon is closer. So this means that its pull is stronger than the sun.

24. Radioactive isotopes put Earth on a light simmer

Four isotopes inside Earth put it on a light simmer. Like a slow cooker, they constantly generate heat within the planet keeping it on a light boil.

These four isotopes are uranium-238 (238U), uranium-235 (235U), thorium-232 (232Th), and potassium-40 (40K). Each number in these radioactive isotopes corresponds to the number of protons and neutrons in its nucleus.

Because of these 4 isotopes, Earth is geologically active and maintains a cozy temperature. The majority of heat transfer is from mid-oceanic ridges and the least is from continental interiors.

25. Heat transfer from convection cycles

Imagine you are boiling water in a pot. If you boil one side of the pot, it warms up where the flame is. When hot water spreads out, it mixes with the cold water.

Eventually, this movement of hot to cold creates a circular motion which is the convection cycle.

Beneath the crust, the convection cycle occurs in the mantle. Because the plastic-like “asthenosphere” acts as a liquid, it makes the convection cycle possible.

26. The lithosphere rides on the asthenosphere

The lithosphere sits on a plasticky layer called the asthenosphere. Because of its buoyancy, the lighter rock floats on it. It spans 80-200 km beneath the surface.

Soon after a dramatic period of Earth heating, the Earth started to cool down. This was when the solid lithosphere layer began to form as continents began to rise up out of the mantle.

The asthenosphere is the untold story of how its fluidity facilitates plate tectonics.

27. Plate tectonics create new rock

Inch by inch, the Earth beneath our feet is moving. But it’s so slow that we don’t even notice it. However, GPS can measure their movements.

Like a giant conveyor belt, one end of a plate is sinking into the Earth transporting whatever is on top of it. At the opposite end, new rock rises from the mantle.

Plate tectonics is the mechanism that recycles Earth’s lithosphere. This breakthrough discovery transformed geology as we know it.

28. Building mountains and orogenies

Plate tectonics are deceptively slow. But they’re never idle. When convergent plates collide, plates thrust upwards to build mountains.

This geologic process of vertical upheaving is the orogenies or mountain building events. Since the beginning of Earth, plate tectonics have carved out chains of mountains that have reshaped the landscape inside and out.

While young rock appear and disappear, cratons are stable pieces of the continent that have lasted over 1 billion years old.

29. Tearing down mountains

From the remarkable process of plates colliding to build mountains. They are only to be dismantled by the process of weathering, erosion and transport.

By mostly water, wind, and ice, mass wasting is the removal of rock due to erosion. Then, it involves the transport of sediments downhill due to gravity.

Currently, Mount Everest is thrusting upwards faster than it being eroded away. But in hundreds of millions of years time, erosion could take its toll shortening it by millimeters each year.

30. A breath of fresh air

There wasn’t always a breath of fresh air on Earth. Methane and nitrogen choked any potential life in Earth’s early atmosphere. But this doesn’t mean that life didn’t exist.

Long ago, tiny, microscopic cyanobacteria flourished in ocean environments. They evolved to carry out photosynthesis anaerobically. The key to their existence was that they didn’t need oxygen to survive.

As a by-product, cyanobacteria released oxygen which was toxic for them. As oxygen filled the oceans and then the atmosphere, this event was the great oxygenation event. This paved the way for aerobic organisms to carry the torch.

31. A struggle for constant oxygen

About 3.5 billion years ago, life existed without photosynthesis. Cyanobacteria used heat from volcanoes or mid-ocean ridges, then released oxygen into the oceans and air.

Because iron rusts when it reacts with oxygen, these layers were red. So the red (oxidized) layers mark a time when there was oxygen. The alternating layers in Banded Iron Formations (BIF) consist of red minerals (oxidized) and (unoxidized) black iron.

These remarkable formations give a sneak peek of how oxygenation was just starting to get a foothold in this geologic period.

32. An ozone layer like sunscreen

The ozone layer shields us from harmful UV rays like sunscreen. The thickness of the ozone layer varies worldwide and by season.

Ozone ranges from 6 to 10 kilometers in the stratosphere. Cross the line, and suddenly there’s less as you go upwards. Ozone is good up high, bad down low.

This colorless gas is made up of three oxygen atoms. It’s the first line of defense that arms us against ultraviolet rays. If you strip Earth of its ozone, you strip it from most life forms.

33. A nearly closed system

The escape velocity of Earth is the speed at which an object must travel to break free of a planet’s gravitational pull into space. Like a mason jar, Earth is nearly a closed system.

We lose some hydrogen from the atmosphere due to its escape velocity. And we get the occasional meteor strike.

But in general, Earth is a closed system because it doesn’t exchange matter from or to the outside. Earth exchanges energy due to incoming solar radiation but little matter leaves or enters.

34. The rock cycle recycles the crust

If you could speed up time, you would see rocks continuously cycling from the surface down into the deep interior of the planet and back up again.

Like a well-oiled machine, rocks transform from igneous, sedimentary to metamorphic over long periods of time.

This process where rocks are created, altered and formed again is the rock cycle.

35. Volcanoes form igneous rocks

Volcanoes are the foundation for igneous rocks. Like a bottle of champagne with a cork in it, liquid rock pools in the magma chamber.

Once you pull the cork, the volcano erupts from the mouth spewing lava. Like wax dripping down the side of a candle, igneous rocks form.

So hot lava drips on the side of volcanoes then cools, hardens and become igneous rocks like granite and feldspar. Without igneous rocks, there wouldn’t be the rock cycle.

36. Metamorphic rocks from pressure

Metamorphic rocks change in form from pre-existing rocks. For example, a rock that was once made of sand is changed or “metamorphosed” into another type of rock from heat and pressure.

When it’s metamorphosed, it’s soft and pliable like cookie dough. This intense pressure for metamorphic rocks comes from inside Earth.

Earth’s major mountain chains contain metamorphic rocks because it’s at plate tectonics boundaries where this intense pressure exists.

37. Sedimentary rocks from compacted sediments

Sedimentary rocks like shale, limestone, and sandstone form from pre-existing rocks. If you start with sand, mud or organic material, these sediment deposits get eroded and transported over time.

This happens because shorelines move back and forth compacting material below like a steam roller. The new layers of sedimentary rock are on top and the older layers are on the bottom.

Like glue, each successive layer cement over tens of millions of years. For example, the Grand Canyon has stacks upon stacks of sedimentary rocks dating back to 2 billion years ago.

38. The youngest rock is the oceanic crust

Hidden beneath Earth’s oceans, underwater volcanoes spew out lava at mid-oceanic ridges (rift valleys). Because divergent plates move apart from each other at these mid-oceanic ridges, magma flows upwards from the mantle beneath.

When the lava hardens, it becomes dark igneous rock “basalt” at rift volcanoes. Because divergent plates fill in the gaps with basalt, oceanic crust is young geologically.

Over time, the plates grow at oceanic crust and older rock is pushed away from mid-oceanic ridges.

39. Earth’s most prominent feature is hidden beneath the ocean

If we removed all oceans in the world, Earth’s most prominent feature would be its underwater mountain chains. There are over 70,000 kilometers of mountains hidden at the bottom of our oceans.

These occur at divergent plates where plates move away from each other. On the flip side, trenches form where plates move toward each other.

For example, the Mariana Trench is the deepest natural point in the world. This is due to the subduction that occurs at two convergent plates.

40. LUCA is the one common descendant

All living things originated from a common ancestor called the Last Universal Common Ancestor (LUCA).

Around 4 billion years ago, two unicellular groups existed as bacteria and archaea. Scientists have found that certain protein families likely descended from the organism.

LUCA was found to withstand hot temperatures. This means they likely thrived in an iron-sulfur-rich lifestyle like deep-sea hydrothermal vents.