However, ongoing experiments using CERN’s Large Hadron Collider (LHC) seek to recreate the energy conditions that would have existed during the Big Bang, which is also expected to reveal physics that go beyond the realm of the Standard Model. According to some, the idea of infinite worlds was first suggested by the pre-Socratic Greek philosopher Anaximander in the sixth century BCE. [2] However, there is debate as to whether he believed in multiple worlds, and if he did, whether those worlds were co-existent or successive. [3] [4] [5] [6] Similarly, all Level II bubble universes with different physical constants can, in effect, be found as "worlds" created by "splits" at the moment of spontaneous symmetry breaking in a Level III multiverse. [64] According to Yasunori Nomura, [36] Raphael Bousso, and Leonard Susskind, [34] this is because global spacetime appearing in the (eternally) inflating multiverse is a redundant concept. This implies that the multiverses of Levels I, II, and III are, in fact, the same thing. This hypothesis is referred to as "Multiverse = Quantum Many Worlds". According to Yasunori Nomura, this quantum multiverse is static, and time is a simple illusion. [66] The multiverse is the hypothetical set of all universes. [a] Together, these universes are presumed to comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The different universes within the multiverse are called "parallel universes", "flat universes", "other universes", "alternate universes", "multiple universes", "plane universes", "parent and child universes", "many universes", or "many worlds". One common assumption is that the multiverse is a "patchwork quilt of separate universes all bound by the same laws of physics." [1] If there were a large (possibly infinite) number of universes, each with possibly different physical laws (or different fundamental physical constants), then some of these universes (even if very few) would have the combination of laws and fundamental parameters that are suitable for the development of matter, astronomical structures, elemental diversity, stars, and planets that can exist long enough for life to emerge and evolve.

Think of it this way, we might see the Universe as being big now, but in the far future, who knows how future generations would view it. Our ancestors didn’t have cars or planes, and they would traverse the world in many months, even years. For them, traveling from point a to b seemed incredibly difficult, and they themselves might have thought, why is the Earth so big? a b c Ijjas, Anna; Loeb, Abraham; Steinhardt, Paul (February 2017), "Cosmic Inflation Theory Faces Challenges", Scientific American, 316 (2): 32–39, doi: 10.1038/scientificamerican0217-32, PMID 28118351 By the 5th century BCE, pre-Socratic philosopher Empedocles became the first western scholar to propose a Universe composed of four elements – earth, air, water and fire. This philosophy became very popular in western circles, and was similar to the Chinese system of five elements – metal, wood, water, fire, and earth – that emerged around the same time. Early atomic theory stated that different materials had differently shaped atoms. Credit: github.com Cyr-Racine, Francis-Yan; Ge, Fei; Knox, Lloyd (18 May 2022). "Symmetry of Cosmological Observables, a Mirror World Dark Sector, and the Hubble Constant". Physical Review Letters. 128 (20): 201301. arXiv: 2107.13000. Bibcode: 2022PhRvL.128t1301C. doi: 10.1103/PhysRevLett.128.201301. PMID 35657861. S2CID 248904936. In terms of its shape, spacetime may exist in one of three possible configurations – positively-curved, negatively-curved and flat. These possibilities are based on the existence of at least four dimensions of space-time (an x-coordinate, a y-coordinate, a z-coordinate, and time), and depend upon the nature of cosmic expansion and whether or not the Universe is finite or infinite.

Further Reading:

https://thumbor.forbes.com/thumbor/960×0/https%3A%2F%2Fblogs-images.forbes.com%2Fstartswithabang%2Ffiles%2F2016%2F07%2F060915_CMB_Timeline150-1200×819.jpg What if we're living in a computer simulation?". The Guardian. 22 April 2017 . Retrieved 12 July 2022. In the 1920s, astronomer Edwin Hubble discovered the universe was not static. Rather, it was expanding; a find that revealed the universe was apparently born in a Big Bang.

Ellis, George; Silk, Joe (16 December 2014), "Scientific Method: Defend the Integrity of Physics", Nature, 516 (7531): 321–323, Bibcode: 2014Natur.516..321E, doi: 10.1038/516321a, PMID 25519115 Filaments of dark matter, called hairs, form when particles of dark matter go through a planet. (Image credit: NASA/JPL-Caltech) In 1915, a few months after Einstein had published his Theory of General Relativity, German physicist and astronomer Karl Schwarzschild found a solution to the Einstein field equations that described the gravitational field of a point and spherical mass. This solution, now called the Schwarzschild radius, describes a point where the mass of a sphere is so compressed that the escape velocity from the surface would equal the speed of light.In other words, at some point in the past, the entire mass of the Universe would have been concentrated on a single point. These discoveries triggered a debate between physicists throughout the 1920s and 30s, with the majority advocating that the Universe was in a steady state (i.e. the Steady State Theory). In this model, new matter is continuously created as the Universe expands, thus preserving the uniformity and density of matter over time. Think about this for a second; it takes us around three days to reach the Moon , approximately seven months to get the closest planet to us, namely Mars , 15 months to reach Venus , six years to reach Jupiter , seven to reach Saturn , 8.5 years to reach Uranus , 9.5 years to reach Pluto – the closest dwarf planet , and twelve years to get to Neptune , the farthest planet.

Answering this question has been a major focus of cosmologists ever since the debate about which model of the Universe was the correct one began. With the acceptance of the Big Bang Theory, but prior to the observation of dark energy in the 1990s, cosmologists had come to agree on two scenarios as being the most likely outcomes for our Universe.It was not until Democritus, the 5th/4th century BCE Greek philosopher, that a Universe composed of indivisible particles (atoms) was proposed. The Indian philosopher Kanada (who lived in the 6th or 2nd century BCE) took this philosophy further by proposing that light and heat were the same substance in different form. The 5th century CE Buddhist philosopher Dignana took this even further, proposing that all matter was made up of energy. The shape of the universe and whether or not it is finite or infinite in extent depends on the struggle between the rate of its expansion and the pull of gravity. The strength of the pull in question depends in part on the density of the matter in the universe. He argues that this "implies that any conceivable parallel universe theory can be described at Level IV" and "subsumes all other ensembles, therefore brings closure to the hierarchy of multiverses, and there cannot be, say, a Level V." [29] Johannes Kepler advanced the model further with his theory of the elliptical orbits of the planets. Combined with accurate tables that predicted the positions of the planets, the Copernican model was effectively proven. From the middle of the seventeenth century onward, there were few astronomers who were not Copernicans. These traditions are best described in the 2nd century CE mathematical and astronomical treatise, the Almagest, which was written by Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy). This treatise and the cosmological model it espoused would be considered canon by medieval European and Islamic scholars for over a thousand years to come. A comparison of the geocentric and heliocentric models of the Universe. Credit: history.ucsb.edu