Briefly describe the evolution of earth
Answers
The relatively calm region of space we occupy in the Solar System today belies a fiery, violent past, and a spine-chilling future. This series explores the geological and natural history of Earth, beginning with the formation of our Solar System, moving on through asteroid impacts and mass extinctions, and ending with the human impact on the environment today. To really grasp the magnitude of the changes our planet has undergone, we need to speed through immense timescales, pausing at important milestones. And this article, the first of the series, starts at the very beginning.
Some 4.6 billion years ago, a giant cloud of gas, called a nebula, collapsed into itself because of its mass and crushed all the gassy material in it into a plane, even as it was constantly spinning. This disc of material is called the protoplanetary disc. Over a period of a hundred thousand years after the collapse, the Sun was formed at the center of this disc, with the rest of the nebular gas swirling around it. Nearly 98% of this gas was just hydrogen and helium. (Our Sun constitutes 98% of the mass of our Solar System today.) Gases and other materials in this protoplanetary disc outside of the Sun started clumping together at various spots. Constant collisions between these bodies formed miniature planets, called planetesimals. These seeds of planets eventually grew in size by pulling more material in due to growing gravitational forces, a process called accretion, to become true planets within 100,000 years after the Sun’s formation. The gas giants, Jupiter and Saturn, and the ice giants, Uranus and Neptune, formed much faster than the four terrestrial planets: Mercury, Venus, Earth, and Mars, did.
Approximately 4.54 billion years ago, a Mars-sized body slammed into the newly formed Earth, partially liquifying the surface and ejecting molten debris into space. This ejecta remained as a ring around our planet for a few months, before coalescing and forming the Moon. Residual gases were still swirling slowly around the Sun, causing streams and waves in space. Elephantine Jupiter got caught up in these currents and started moving inward toward the Sun. The movement of this giant, with its powerful gravity wreaking havoc as it danced around, dislodged asteroids and sent them flying inwards into the planets. In the next few million years, the Earth and other terrestrial planets went through a period of constant battering by asteroids and other smaller bodies. This period in the solar system’s history is called the Late Heavy Bombardment. Fortunately, Saturn soon started pulling Jupiter back, toward where it is today, even as the Solar wind stripped away all of the residual gas in the solar system into interstellar space.
At this point, Earth was still cooling from the formation of the Moon, and the period of bombardment kept it agitated and volcanically active. At some point, asteroids or comets containing water ice slammed into the Earth, thereby bringing a lot of water vapor to the Earth. Once the Earth cooled, this vapour condensed and fell as rain on the planet. Volcanic activity still continued and even under the newly forming oceans, super-volcanoes persisted. Lava constantly flowed on the surface for nearly 700 million years.
We know all of these intricate details to a near approximate date by studying rocks on our planet. Rocks hold records of all kinds of transitions that they have undergone. They record their own formation and grow over millions of years, keeping evidence of life and planet activity within. The field of geology that studies and dates rock layers is called Stratigraphy. This helps scientists figure out the age of a lot of geological processes, and has enabled them to put together a geological time scale for our Earth.
Answer:A series exploring the natural history of Earth, beginning with the formation of our Solar System, moving on through asteroid impacts and mass extinctions, and ending with the human impact on the environment.
The relatively calm region of space we occupy in the Solar System today belies a fiery, violent past, and a spine-chilling future. This series explores the geological and natural history of Earth, beginning with the formation of our Solar System, moving on through asteroid impacts and mass extinctions, and ending with the human impact on the environment today. To really grasp the magnitude of the changes our planet has undergone, we need to speed through immense timescales, pausing at important milestones. And this article, the first of the series, starts at the very beginning.
Some 4.6 billion years ago, a giant cloud of gas, called a nebula, collapsed into itself because of its mass and crushed all the gassy material in it into a plane, even as it was constantly spinning. This disc of material is called the protoplanetary disc. Over a period of a hundred thousand years after the collapse, the Sun was formed at the center of this disc, with the rest of the nebular gas swirling around it. Nearly 98% of this gas was just hydrogen and helium. (Our Sun constitutes 98% of the mass of our Solar System today.) Gases and other materials in this protoplanetary disc outside of the Sun started clumping together at various spots. Constant collisions between these bodies formed miniature planets, called planetesimals. These seeds of planets eventually grew in size by pulling more material in due to growing gravitational forces, a process called accretion, to become true planets within 100,000 years after the Sun’s formation. The gas giants, Jupiter and Saturn, and the ice giants, Uranus and Neptune, formed much faster than the four terrestrial planets: Mercury, Venus, Earth, and Mars, did.
Approximately 4.54 billion years ago, a Mars-sized body slammed into the newly formed Earth, partially liquifying the surface and ejecting molten debris into space. This ejecta remained as a ring around our planet for a few months, before coalescing and forming the Moon. Residual gases were still swirling slowly around the Sun, causing streams and waves in space. Elephantine Jupiter got caught up in these currents and started moving inward toward the Sun. The movement of this giant, with its powerful gravity wreaking havoc as it danced around, dislodged asteroids and sent them flying inwards into the planets. In the next few million years, the Earth and other terrestrial planets went through a period of constant battering by asteroids and other smaller bodies. This period in the solar system’s history is called the Late Heavy Bombardment. Fortunately, Saturn soon started pulling Jupiter back, toward where it is today, even as the Solar wind stripped away all of the residual gas in the solar system into interstellar space.
At this point, Earth was still cooling from the formation of the Moon, and the period of bombardment kept it agitated and volcanically active. At some point, asteroids or comets containing water ice slammed into the Earth, thereby bringing a lot of water vapor to the Earth. Once the Earth cooled, this vapour condensed and fell as rain on the planet. Volcanic activity still continued and even under the newly forming oceans, super-volcanoes persisted. Lava constantly flowed on the surface for nearly 700 million years.
Explanation: