Although increasingly advanced astronomical methods have yet to accurately determine the time and manner of the creation of the universe, observation of galaxies many billions of years old has allowed cosmologists to deconstruct the process, the catalyst for which, dubbed ” Big Bang Theory” occurred approximately 15 billion years ago. years ago.
The origin, not necessarily of the universe, but what can perhaps be more accurately designated the physical dimension, occurred when a single, densely packed ball of matter, energy, and space reached unfathomable temperatures and cataclysmically exploded, covering an area the size of our solar system just minutes after launch. Before condensing into subatomic particles, it manifested as a faint glow of radiation called the cosmic microwave background.
Collecting and cooling, this matter took its earliest form as galaxies and primitive stars, but continued to expand as a whole.
Our own solar system is estimated to have been created five billion years ago, at which time the universe was two-thirds its current size.
After millennia of cohesion, the universe itself consists of planets, dwarf planets, moons, satellites, asteroids, meteorites, comets, and an interplanetary medium, which in turn is made up of gas and dust.
The expansion of the universe has been determined by several leading astronomers. Using photographic spectroscopy and examining various patches at the Lowell Observatory in Flagstaff, Arizona, Vesto Slipher, for example, measured the speed of light with spectral lines, while Edwin Hubble and his assistant, Milton Humason, concluded that the patches studied were actually galaxies. Because most of these spectra were of longer wavelengths, or redder, Slipher himself concluded, based on the Doppler shift, that the galaxies were moving away from Earth.
Using a graph, in which the galaxy’s recessional velocity was plotted on the vertical axis and its distance on the horizontal, Hubble determined that the further the galaxy was from Earth, the faster it was receding in all directions, indicating that the universe is both continuously expanding and accelerating. The result, expressed as the Hubble constant, states that speed is proportional to distance. Although its numerical value has yet to be calculated, advanced tools and techniques, including the Hubble Space Telescope itself, have brought that number within the realm of reality.
Conceptualizing something as virtually infinite as the universe to a finite entity like man with limited brain capacity is difficult, but the universe itself can be subdivided into galaxies, galaxy clusters, and supercluster clusters. Current estimates conclude that there are tens of billions of galaxies in the observable universe, of which Andromeda is visible to the naked eye from the Northern Hemisphere and two small satellite galaxies are observable from the Southern Hemisphere: the Large and Small Clouds of Magellan.
Analysis of the origin of the universe leads naturally to speculation of its termination, if any. Some believe that all galaxies will recede until they slow down, stop moving, and then recede, until all matter once again collides into a single ball, thus reversing the dynamics of the Big Bang. Alternatively designated the “oscillating theory of the universe” or the “Bang-Bang-Bang” theory, it would involve a chain reaction of explosion, recession, and remission every ten billion years.