Journey through cosmic evolution

The chapters "Known composition of the Physical World" and "Origin of the Physical Worlds" in The Evolution of Knowledge provide a scientific and metaphysical overview of the universe's structure and its beginning.

Known Composition of the Physical World

The Physical World, also referred to as the Cosmos or Universe, encompasses the entirety of matter, energy, space, and time. Current theories define it as a spacetime continuum with four dimensions—three spatial and one temporal—and estimate its age at approximately 13.7 billion years.

Key characteristics of its composition include:

• Scale and Structure: The Cosmos holds between 100 billion and 2 trillion galaxies, each containing billions of stars; the total number of stars in the universe may reach 300 sextillion.

• Expansion: All stars and galaxies appear to be receding from Earth at an increasing speed proportional to their distance, proving that the Universe is expanding at an accelerated pace.

• The Observable Universe: The observable radius is roughly 46 billion light-years, though the actual Universe is theorized to be 10 to 23 times larger than the part we can see.

• Matter and Energy: Ordinary matter (protons, neutrons, and electrons) accounts for only 5% of the total composition. The remaining 95% consists of speculative dark matter and dark energy, which are inferred by their gravitational effects and pressure on expansion.

• Elemental Makeup: Of the ordinary matter known, 90% is hydrogen, 8% is helium, and only 2% comprises the rest of the periodic table.

Origin of the Physical Worlds

The Big Bang is the prevailing cosmological theory explaining the origin of the universe, suggesting it began as a totally condensed singular minuscule entity that exploded.

• Evidence for the Big Bang: The primary proofs are the redshift of galaxies and the discovery of Cosmic Microwave Background Radiation (CMBR), a uniform haze of radiation that serves as a remnant of a very dense, hot primordial state.

• Formation of Matter and Forces: In the first fractions of a second after the explosion, fundamental forces appeared serially: first gravity, then the electroweak and nuclear forces.

• Atomic Evolution: Two minutes after the explosion, protons and neutrons fused into atomic nuclei. It took approximately 388,000 years for the temperature to drop enough for electrons to combine with nuclei to form the first atoms.

• Stellar Nucleosynthesis: Stars formed from interstellar clouds condensed by gravity and acted as thermonuclear fusion reactors. They fused hydrogen into helium, then helium into heavier elements like carbon, oxygen, and eventually iron.

• Supernovae and Elemental Distribution: When high-mass stars die, they explode as supernovae, recombining and throwing elements into space. This expelled dust enriches clouds that eventually evolve into new solar systems, planets, and the building blocks of life.