The Big Bang – the building material for the cosmos
The standard model of the Big Bang assumes that helium (He) and heavy hydrogen (deuterium H2) appeared at the very origin of our universe (time equals zero) along with very fine dust. The electronic charge of the atom is determined by the relative number of electrons and protons and the polarity is a result of the combined atomic spins of the electrons in orbit around the nucleus. Electrical charge and magnetic polarity play an important role in the early formation of the molecular clouds. These clouds of elements in the form of molecular clouds, combined with dust to fill the space in the cosmos, but not uniformly. The molecular clouds formed first a cosmic structure looking somewhat like a sponge, with dark matter, gas and galaxies outlining sparse voids. These clumps are protostars, where stars initiate.
Space primarily consists of low density gas and dust with about 75% of the mass of the gas being hydrogen and 25 % helium. Traces of other elements are found. The dust is very fine particles, comparable to cigaret smoke. The gas and dust is not uniformly distributed with a complex mixture of cool dense clouds twisted in tangles of hot low density gas. Water in the form of ice is found.
Star formation in the galaxies began in a manner analogous to water condensing in clouds and generating raindrops. These clumps of matter had different densities and those with similar properties tended to group together with gravity as the main driving force. Accretion from the molecule generated an atomic buzz that further drove the clumps of molecular gas and dust to associate. The violent associations generated shock waves which, in the presence of strong magnetic fields, initiated the formation of light sources or stars. Stars would typically form in the spiral arms of galaxies such as M83, near the center of the top banner, and M51 in the photo gallery.
The massive stars, e.g. Alnitak, Alnilam and Mintaka in the belt of Orion, are many times larger than our Sun. And, the very strongest magnetic fields are seen at Alnitak and at the Orion nebula, as summarized by Young in Sky and Telescope (Oct 2015). See also /http://www.skyandtelescope.com/sky-and-telescope-magazine/beyond-the-printed-page/massive-star-formation-x-marks-the-spot/
Neutron stars form as giant atomic nuclei with essentially no vacant space and the density is essentially that of an atomic nucleus. They emit radio waves as well as x-ray and gamma ray radiation. They are discovered by radio telescopes rather that optical telescopes. Rapidly rotating neutron stars emit a regular signal as the star rotates. Radiation from the rotating Crab pulsar gives signals at 30 per second. Neutron stars can typically have masses of many solar masses, i.e. many times greater than our sun.
Early on astronomers discovered that the universe was expanding, driven by gravitational repulsion. The amount of mass required to cause that acceleration observed was many times the mass expected from planets, dust and other observed matter. The term dark matter was assumed to associate with this missing mass.
Galaxies, black holes and galaxy central masses
“Black hole” is the name given to the location in space time where extraordinary mass has accumulated due to immense gravitational attraction. The gravity concentration of a black hole builds from a neutron star as it attracts more mass from the surrounding dust etc, of the cosmos. Masses of 10 to 25 solar masses occur here. As the black hole attracts more mass, and the mass reaches from 40 to 100 solar masses, any gasses are purged, increasing the density. Galaxies typically have black holes at their center..
Collapsing neutron stars are central to the galaxy central masses (bulge) and, as a result, to the velocity of the stars spinning around them. This is most notable to galaxies having the classic central bulge.
Our universe is defined by the millions of galaxies which are seen by telescopes. The universe appears to be flat and expanding with the galaxies accelerating away from each other, driven by reactions to dark matter, which constitutes an overwhelmingly large portion of the matter of the universe. There is no spacial center, no origin. The calculation of the age of the universe can be accomplished with a velocity for two different galaxies and the distance between them. We have millions of galaxies from which to choose and modern astronomical telescopes have given the required velocities and distances. Velocities are measured by redshift, which is the astronomical adaptation of the doppler shift effect found in sound when a train horn appears to change frequency as it passes. Distances are established by using the parallax principle and the comparative luminosity of the parent stars. The generally accepted value for the age of the universe is 13.8 billion years (Seeds, M. A and Blackman, D. E, 1010) (Seeking the Cosmic Dawn).