Key Agreement on Earth’s History

The Earth, like the other planets, is thought to have formed 4.5 billion years ago as a frozen cloud of dust and gases left over from the Sun’s birth. The interior of Earth remained solid and relatively chilly for 500 million years, perhaps 2,000 degrees Fahrenheit. According to the best available evidence, the principal constituents were iron and silicates, with little amounts of other elements, some of which were radioactive. Energy produced by radioactive decay, principally of uranium, thorium, and potassium, progressively heated Earth over millions of years, melting some of its elements. The iron melted first, and because it was heavier, it sunk to the centre.

This pushed up the silicates it had discovered. The iron eventually reached the centre, over 4,000 miles underground, and began to deposit after many years. There were no eyes around to see the chaos that must have occurred on the face of the Earth at the time? On the surface, there are massive heaves and bubblings, bursting volcanoes, and pouring lava engulfing everything in sight. The iron at the centre eventually accumulated to form the core. As the Earth cooled, a thin but fairly stable crust of solid rock formed around it. Depressions in the crust were natural basins where water coming from the planet’s interior via volcanoes and fractures gathered to form the oceans. Earth gradually took on its current appearance.

Early theories of earth origin

The following sections address the key early theories of the earth’s origin.

Nebular Hypothesis – Immanuel Kant established the Nebular Hypothesis, which was later refined by Pierre Laplace in 1796. The planets, according to this theory, were produced from a cloud of material linked with a young sun that rotated slowly.

• Chamberlain and Moulton proposed in 1900 that a wandering star approached the sun, causing a cigar-shaped extension of material to detach from the solar surface. This fragmented matter continued to orbit around the sun, gradually condensing into planets.

• A partner was thought to be coexisting with the sun in binary theories.

• Otto Schmidt (in Russia) and Carl Weizascar (in Germany). revised the Nebular Hypothesis in 1950. They claimed that the sun was surrounded by a solar nebula composed primarily of hydrogen and helium, as well as dust. The development of a disk-shaped cloud resulted from particle friction and collision, and planets were formed by the accretion process.

Origin of Earth Modern Theories

• The Big Bang Theory describes how the universe began. The expanding universe hypothesis is another name for it

• Abbe Georges Lemaitre, a Belgian astronomer was the first to propose a theory for the Universe’s genesis in 1927. The fact that the universe is expanding was discovered by Edwin Hubble

• According to this hypothesis, all matter that made up the cosmos resided in a singularity (a tiny ball) with an unimaginably small volume, unlimited temperature, and limitless density

• The big bang occurred approximately 13.7 billion years ago. The little ball exploded, resulting in a massive expansion that continues to this day. Within fractions of a second following the bang, there was rapid expansion. After that, the expansion stalled.

Some of the energy was turned into matter as the universe expanded. The first atom began to form within the first three minutes of the great bang

• Temperature plummeted to 4500 K within 300,000 years of the big bang, giving origin to atomic stuff. The majority of the atoms created were hydrogen, with traces of helium and lithium. Huge clouds of these elements coalesced into stars and galaxies because of gravitation

• The Big Bang theory and Hoyle’s concept of steady state were formerly the only two possibilities for explaining the origin of the universe

• The steady state theory assumed that the universe was approximately the same at all times

• However, as more evidence for the expanding cosmos became available, the Big Bang theory was proven, which claims that the universe was created by a single explosive explosion of a very small amount (tiny ball) of high density and temperature matter

Development of earth

With a thin atmosphere of hydrogen and helium, the earth was a desolate, stony, and hot object.

Lithosphere – As the density of the earth increased, so did the temperature, and the materials began to segregate based on their densities. The heavier components, such as iron, flowed to the centre, while the lighter elements moved to the surface. The earth cooled, solidified, and condensed into a smaller size throughout time, forming the crust (the outer layer of the earth).

• Starting at the surface, the crust, mantle, outer core, and inner core are the distinct layers of the earth. Density rises from the crust to the core

• Atmosphere – Because the solar wind was strongest near the sun, it blasted a lot of gas and dust off the terrestrial planets, including Mercury, Venus, Earth, and Mars. Gases and water vapour escaped from the interior of the earth during the cooling phase, kicking off the formation of the current atmosphere. Water vapour, carbon dioxide, nitrogen, methane, ammonia, and modest amounts of free oxygen dominated the early atmosphere. The process of releasing gases from the earth’s interior is known as “degassing.”
• The regular volcanic eruptions supplied water vapour and gases to the atmosphere. Water vapours condensed as the earth cooled, resulting in rain. The carbon dioxide in the atmosphere was absorbed in precipitation, lowering the temperature even further, resulting in additional condensation and rain. Oceans were formed as rainwater was gathered in depressions. For a long time, life was restricted to the oceans. Through the process of photosynthesis, oceans became saturated with oxygen, and oxygen began to flood the atmosphere around 2,000 million years ago

Conclusion

We can conclude that The “last universal common ancestor” (the hypothetical latest living organism from which all organisms now living on Earth descend, or, in other words, the most recent According to current theory, the common ancestor of all extant life on Earth lived between 3.5 and 3.8 billion years ago. The actual mechanism for its genesis, however, remains unknown.

While the circumstances that led to life on Earth are undoubtedly unique, there is no reason to believe they are unique to the planet. As Richard Dawkins points out, if the cosmos has a billion billion planets (which some scientists believe is a conservative estimate), the chances of life forming on one of them aren’t particularly high.If, as some physicists believe, our universe is simply one of many in a multiverse, each of which has a billion billion planets, then life will almost At least one of them will  emerge.