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In physical cosmology, the uncapitalized term cosmic signifies a subject with a relationship to the universe, such as 'cosmic time' (time since the Big Bang), 'cosmic rays' (high energy particles or radiation detected from space), and 'cosmic microwave background' (microwave radiation detectable from all directions in space).
The magnitude of the energy of cosmic ray flux in interstellar space is very comparable to that of other deep space energies: cosmic ray energy density averages about one electron-volt per cubic centimetre of interstellar space, or ≈1 eV/cm 3, which is comparable to the energy density of visible starlight at 0.3 eV/cm 3, the galactic magnetic ...
Cosmology deals with the world as the totality of space, time and all phenomena. Historically, it has had quite a broad scope, and in many cases was found in religion. [ 28 ] Some questions about the Universe are beyond the scope of scientific inquiry but may still be interrogated through appeals to other philosophical approaches like dialectics .
The interpretation of the cosmic microwave background was a controversial issue in the late 1960s. Alternative explanations included energy from within the solar system, from galaxies, from intergalactic plasma and from multiple extragalactic radio sources. Two requirements would show that the microwave radiation was truly "cosmic".
Alan Guth and Alexei Starobinsky proposed in 1980 that a negative pressure field, similar in concept to dark energy, could drive cosmic inflation in the very early universe. Inflation postulates that some repulsive force, qualitatively similar to dark energy, resulted in an enormous and exponential expansion of the universe during its earliest ...
Cosmic ray astronomy is a branch of observational astronomy where scientists attempt to identify and study the potential sources of extremely high-energy (ranging from 1 MeV to more than 1 EeV) charged particles called cosmic rays coming from outer space.
General relativity predicts that energy is equivalent to mass, and therefore, if the vacuum energy is "really there", it should exert a gravitational force. Essentially, a non-zero vacuum energy is expected to contribute to the cosmological constant , which affects the expansion of the universe .
A positive vacuum energy density resulting from a cosmological constant implies a negative pressure, and vice versa. If the energy density is positive, the associated negative pressure will drive an accelerated expansion of the universe, as observed. (See Dark energy and Cosmic inflation for details.)