What was life like on Earth 4 billion years ago? The Precambrian Period encompasses the time when the Earth was formed, roughly 4.6 billion years ago.
Earth - Habitable Planet
Our globe was once a massive, red-hot, boiling sea of molten rock. The Earth gradually cooled, and a thin crust formed on its surface. The core, on the other hand, remained extremely hot. Water vapor produced as the cooling advanced, and it escaped into the atmosphere. The water vapor in this cloud condensed to create the clouds that brought rain, and soon storms raged around the globe, chilling the surface even more and generating floods. Oceans and seas were formed as a result of the floods.
When did life on this habitable planet Earth begin?
About 3 billion years ago, the first forms of life on Earth evolved in the form of primitive, single-celled creatures such as bacteria. Over a billion years later, multicellular life appeared, and it was only in the last 570 million years that the kinds of life forms we are familiar with appeared. Arthropods, or soft-bodied worm-like organisms that lived in the waters, were the first, followed by fish that flooded the oceans. Some sea species made their way to the shore, where they evolved into amphibians and land mammals.
Aquatic plants developed into land plants, while land plants evolved into forests. Mammals appeared 200 million years ago, while Early Man appeared barely 200,000 years ago. So, humans have only been on the planet for 0.004% of its history!
Structure of the Earth
There are five layers to the Earth. Physically and chemically, each of these layers is distinct. The inner and outer cores, the lower and upper mantle, and the crust are the components. Because of the great pressure surrounding it, the Earth’s inner core is a massive red hot metallic ball of iron that remains solid even at such extreme temperatures. A red hot liquid layer of iron and nickel makes up the outer core. The Earth’s magnetic field is created by the movement of these moving metals. The lower mantle is composed of solid rock that is hot enough to melt but remains solid due to pressure exerted on it. Both solid and molten rock make up the upper mantle. The crust, the Earth’s thinnest layer, protects the planet’s surface.
The continental crust, which is primarily granite, lies under land masses. The oceanic crust is a rock that exists under the oceans and is primarily made up of basalt.
Habitable Atmosphere on Earth for living
The atmosphere is the layer of gases that surrounds the Earth and is known as air. Air contains 78.9% nitrogen, 20.95 percent oxygen, 0.93 percent argon, 0.03 percent carbon dioxide, and trace amounts of other gases, as well as water vapor. Earth is protected by the atmosphere, which acts as a large blanket of insulation. It absorbs the Sun’s heat and retains it within the atmosphere, allowing the Earth to remain warm. It also keeps the Earth’s total temperature relatively constant, particularly between night and day. Our weather patterns and climate are shaped in large part by the atmosphere.
The majority of the planets in our solar system, as well as certain moons, have atmospheres. Their atmospheres, on the other hand, are vastly different from that of Earth.
The fifth and outermost layer of the atmosphere is known as the exosphere. It starts at a distance of around 500 kilometers from the Earth’s surface and finishes at a distance of about 10,000 kilometers. The planet’s first line of protection against the Sun’s radiation is the exosphere. It’s also the first layer to make touch with Earth, shielding it from meteorites, asteroids, and cosmic rays. The exosphere’s air is quite thin, and it’s largely made up of helium and hydrogen. Other gases, such as atomic oxygen and carbon dioxide, can also be detected in trace amounts. The molecules in the exosphere do not clash like they do in the lower levels of the atmosphere because the air is so thin. The majority of the molecules make it back to the lower levels of the atmosphere, although a few escape into space.
Satellites can be placed in the exosphere since there is very little friction and they can easily orbit without being disrupted. Finally, the exosphere merges with the void of space, where there is no atmosphere.