How The Life Begin

The history of Earth concerns the development of  planet   Earth  from its formation to the present day.Nearly all branches of  natural science  have contributed to understanding of the main events of Earth's past, characterized by constant  geological change and biological  evolution . The geological time scale (GTS), as defined by international convention,depicts the large spans of time from the beginning of the Earth to the present, and its divisions chronicle some definitive events of Earth history. (In the graphic:  Ga  means "billion years ago";  Ma , "million years ago".) Earth formed around 4.54 billion years ago, approximately one-third the  age of the universe , by  accretion  from the  solar nebula . Volcanic  outgassing probably created the primordial  atmosphere  and then the ocean, but the early atmosphere contained almost no  oxygen . Much of the Earth was molten bec...

History of the center of the Universe Figure of the heavenly bodies — An illustration of the Ptolemaic geocentric system by Portuguese cosmographer and cartographer  Bartolomeu Velho , 1568 (Bibliothèque Nationale, Paris), depicting Earth as the centre of the Universe. The center of the Universe is a concept that lacks a coherent definition in modern  astronomy ; according to standard  cosmological  theories on the  shape of the universe , it has no center. Historically, the center of the Universe had been believed to be a number of locations. Many mythological cosmologies included an  axis mundi , the central axis of a flat Earth that connects the Earth, heavens, and other realms together. In the 4th century BCE Greece, the  geocentric model  was developed based on astronomical observation, proposing that the center of the Universe lies at the center of a spherical, stationary Earth, around which the sun, moon, planets, a...

Loop quantum gravity Loop quantum gravity ( LQG ) is a theory of  quantum gravity , merging  quantum mechanics  and  general relativity , making it a possible candidate for a  theory of everything . Its goal is to unify gravity in a common theoretical framework with the other three  fundamental forces  of nature, beginning with relativity and adding quantum features. It competes with  string theory that begins with  quantum field theory and adds gravity. From the point of view of  Einstein 's theory, all attempts to treat gravity as another quantum force equal in importance to electromagnetism and the nuclear forces have failed. According to Einstein, gravity is not a force – it is a property of  spacetime itself . Loop quantum gravity is an attempt to develop a quantum theory of gravity based directly on Einstein's geometric formulation. To do this, in LQG theory space and time are  quantized , analogously to the w...

N ext point will be quantum loop gravity

This subfield originated in 1999 by  Martin Bojowald , and further developed in particular by  Abhay Ashtekar  and  Jerzy Lewandowski , as well as  Tomasz Pawłowski  and  Parampreet Singh , et al. In late 2012 LQC represents a very active field in  physics , with about three hundred papers on the subject published in the literature. There has also recently been work by  Carlo Rovelli , et al. on relating LQC to the  spinfoam -based  spinfoam cosmology . However, the results obtained in LQC are subject to the usual restriction that a truncated classical theory, then quantized, might not display the true behaviour of the full theory due to artificial suppression of degrees of freedom that might have large quantum fluctuations in the full theory. It has been argued that singularity avoidance in LQC are by mechanisms only available in these restrictive models and that singularity avoidance in the full theory can still be obtained ...

Loop  quantum cosmology  (LQC) is a  finite ,  symmetry -reduced model of  loop quantum gravity  ( LQG ) that predicts a "quantum bridge" between contracting and expanding  cosmological  branches. The distinguishing feature of LQC is the prominent role played by the  quantum geometry  effects of loop quantum gravity (LQG). In particular,  quantum geometry  creates a brand new repulsive force which is totally negligible at low space-time curvature but rises very rapidly in the  Planck regime , overwhelming the classical gravitational attraction and thereby resolving  singularities of general relativity . Once singularities are resolved, the conceptual paradigm of  cosmology changes and one has to revisit many of the standard issues—e.g., the " horizon problem "—from a new perspective. Since LQG is based on a specific quantum theory of  Riemannian geometry , geometric observables display a f...