Īs the universe's expansion is accelerating, all currently observable objects, outside the local supercluster, will eventually appear to freeze in time, while emitting progressively redder and fainter light. In November 2018, astronomers reported that the extragalactic background light (EBL) amounted to 4 ×10 84 photons. Using the critical density and the diameter of the observable universe, the total mass of ordinary matter in the universe can be calculated to be about 1.5 ×10 53 kg. The radius of the observable universe is therefore estimated to be about 46.5 billion light-years. Sometimes astrophysicists distinguish between the visible universe, which includes only signals emitted since recombination (when hydrogen atoms were formed from protons and electrons and photons were emitted)-and the observable universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional physical cosmology, the end of the inflationary epoch in modern cosmology).Īccording to calculations, the current comoving distance to particles from which the cosmic microwave background radiation (CMBR) was emitted, which represents the radius of the visible universe, is about 14.0 billion parsecs (about 45.7 billion light-years) the comoving distance to the edge of the observable universe is about 14.3 billion parsecs (about 46.6 billion light-years), about 2% larger. No signal can travel faster than light, hence there is a maximum distance (called the particle horizon) beyond which nothing can be detected, as the signals could not have reached us yet. It refers to the physical limit created by the speed of light itself. The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth. That is, the observable universe is a spherical region centered on the observer. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. Initially, it was estimated that there may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on data from New Horizons. The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.
0 kommentar(er)
