Nice Model : A Theory for Formation of Solar System

Formation of Solar System:

According to the conventional big bang model of cosmology, time and the cosmos originated as a singularity roughly 14 billion years ago. Our cosmos began with the Big Bang, an explosion of space itself. Space expanded, the universe cooled, and the simplest elements were created, starting from extraordinarily high density and temperature. Gravity brought matter together throughout time to build the first stars and galaxies. Researchers have discovered for the first time that some of the heavier elements in the periodic table are generated when two neutron stars collide and burst cataclysmically. Light elements such as hydrogen and helium were developed during the Big Bang, while heavier metals such as iron are created by fusion in the centres of stars.

 The Sun and the planets emerged from a cloud of gas and dust termed the solar nebula 4.6 billion years ago. The collapse of the solar nebula was most likely triggered by a shock wave from a nearby supernova explosion. The Sun formed in the centre, with the planets surrounding it in a thin disc. Stars are formed when gas and dust clump together and collapse due to gravity, becoming stars. From the time the first gas cloud begins to compress until the star is formed and shines like the Sun, star creation takes about a million years.

'Runaway accretion' is the term for the ultimate step of accretion. Planetesimals are swept up into well-defined zones around the sun that roughly correspond to the current orbits of terrestrial planets. Eventually, the process produces a few huge planetary bodies. Planet formation is influenced by two mechanisms. As the gases in the molecular cloud cool, solid dust grains form, and accretion is the collision of the dust grains to create clumps and larger bodies, some of which evolve into planets. The stages begin 6600 million years ago and include the development of the core, the mantle, oceanic-type crust, ancient platforms, and consolidation (the current stage), after which there should be no more earthquakes or volcanic activity.

Earth formed as gravity drew spinning gas and dust in to become the third planet from the Sun some 4.5 billion years ago when the solar system stabilized into its current shape. Although "the core accretion hypothesis," "the disc instability theory," and "the pebble accretion theory" are three major ideas that explain how Earth formed. According to a recent study, Jupiter was most likely the first planet to form in the solar system. Its existence may have had an impact on how the planets evolved into the current order. Jupiter is primarily made up of hydrogen. 

The simple, fundamental gas, a key component of the sun, makes up 90% of the atmosphere. Helium makes up nearly 10% of the universe. Compounds including ammonia, sulfur, methane, and water vapour make up a very small portion of the atmosphere.

The giant-impact idea is the most widely accepted today. It is suggested that the Moon arose as a result of a collision between the Earth and a tiny planet the size of Mars. The Moon was formed when the debris from this impact gathered in an orbit around Earth. And this theory of the formation of the moon is called “the giant-impact theory.”

Four Stages of formation of Solar System:

Scientists believe that terrestrial planets, such as Earth, originated billions of years ago by clumping together dust and gas into hot blobs of molten metal and rock. 

After becoming distinct planets, they went through four stages of development: 

1. differentiation
2. cratering
3. flooding
4. surface evolution.

1. Differentiation - Layer formation:

The separation of different constituents of planetary materials, resulting in the production of discrete compositional layers, is known as planetary differentiation. Denser stuff sinks to the centre, whereas lighter material rises to the surface. When the worlds were still forming and the Solar System was still a tumultuous place, differentiation began. There was a lot of stony debris in the Solar System. The kinetic energy of these fragments was transformed into thermal energy when they slammed against the Earth. Accretion is the process that created the Earth. This "gravity-driven" process involves the gravitational attraction of material near the solar disc to the expanding Earth.

Jovian planets are distinct: Despite their oddity, jovian planets have something in common with solid worlds. Heavy minerals have sunk to the core to some extent, while lighter materials have risen to the top. As a result, they were heated by accretionary heat as well as gravitational release.

The conditions that must exist for a planet to differentiate are It must be made up of a variety of materials with varying densities, and the materials within must be able to flow. Perhaps the most momentous event in the Earth's history was the differentiation, and organization, of its layers. It finally resulted in the construction of a core, crust, and continents. To create an ocean and atmosphere, light elements were propelled from the interior.

Differentiation is arguably the most momentous occurrence in Earth's history. It resulted in the formation of the core, mantle, and crust, as well as continents. Differentiation caused gases from the moving interior to escape, resulting in the formation of the atmosphere and seas.

2. Cratering - Impacts and Scars:

Craters are the most prevalent surface features on several solid planets and moons, including Mercury and our own Moon. Numerous round holes cover this area of the Moon. Each of these impact craters was created when an asteroid or comet crashed with the Moon's surface. Cratering is a principal shaper of planetary surfaces with no active interiors, as well as those with little atmosphere and weather to obscure impacting features. This data leads us to believe that impact cratering happens across the Solar System. There are several craters on every planet in our Solar System. This was especially true in the past when our solar system had considerably more asteroids than it does now.

Comets and Asteroids are the sources of catering to our solar system. There are several craters on every planet in our Solar System. This was especially true in the past when our solar system had considerably more asteroids than it does now. Mercury has the most cratering.

Impact craters can give information about the age of a planet's surface as well as the nature and chemistry of that surface at the time the crater was produced. Scientists may analyze a planet's geological history using impact craters, even if the records are buried beneath the surface. Outward pressure drives the rock near the crater's edge upward, forming a rim, while underground material is expelled during an impact.

The newly formed planet's crust cools over time, but the bombardment of planetesimals that created it in the first place continues, and the impacts form craters because the planet is no longer molten. Some of the collisions may pierce the crust and reach the molten mantle. The frequency of impacts during the early phases of planetary formation is extremely high, as indicated by Mercury and the moon, two planets with ancient surfaces that have remained virtually intact since their formation. Both planets have a lot of craters.

3. Flooding - Lava covers everything:

The crust of a planet breaks while cratering continues — and partly as a result of it — and lava bursts through and flows over the continent, smoothing and filling the craters. During this period of planetary formation, water vapour also poured through the fissures on Earth. It ascended into the atmosphere and rained down, forming oceans and other bodies of water. On other planets in the solar system, the lava flow was not accompanied by a water deluge. The impacts of lava flooding are more visible in these worlds.

4. Surface Evolution - Changing Landscape:

Surface evolution, the final step of planetary creation, takes billions of years. The movement of tectonic plates, as well as the influence of air motions and water, slowly modify the planet's face. The collision of tectonic plates forces mountains to rise and continents to shift, while rain and wind gradually wear away the surface, erasing any evidence of the chaotic early stages of planetary formation. In the case of Earth, radioactivity in the core causes it to become hotter than it was when it originated, which could be one of several reasons why life evolved.