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The observable universe is a ball-shaped region of the universe consisting of 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.
Today the universe has expanded into an age and size that is physically only in parts observable as the observable universe, which is approximately 93 billion light-years in diameter at the present day, while the spatial size, if any, of the entire universe is unknown.
Observable universe, the region of space that humans can actually or theoretically observe with the aid of technology. The observable universe, which can be thought of as a bubble with Earth at its centre, is differentiated from the entirety of the universe, which is the whole cosmic system of
The featured image illustrates the observable universe on an increasingly compact scale, with the Earth and Sun at the center surrounded by our Solar System, nearby stars, nearby galaxies, distant galaxies, filaments of early matter, and the cosmic microwave background.
The universe contains all the energy and matter there is. Much of the observable matter in the universe takes the form of individual atoms of hydrogen, which is the simplest atomic element, made of only a proton and an electron (if the atom also contains a neutron, it is instead called deuterium).
The origin, evolution, and nature of the universe have fascinated and confounded humankind for centuries. New ideas and major discoveries made during the 20th century transformed cosmology – the term for the way we conceptualize and study the universe – although much remains unknown.
First, the observable universe is everything that we've been able to see or observe thus far. And second, the universe, or the whole universe, means everything that exists, or has existed, or will exist. More specifically, the observable universe is the region of space visible to us from Earth.
In physics, we usually distinguish between these two notions of universe as, one, the observable universe, which is everything whose existence we've thus far been able to confirm or observe, or could, in principle, observe if we pointed our telescopes at it, and two, the Universe with a capital U, or the whole universe, which is everything that ...
Discover the universe: Learn about the history of the cosmos, what it's made of, and so much more.
Jul 12, 2022 · NASA explores the unknown in space for the benefit of all, and Webb’s first observations tell the story of the hidden universe through every phase of cosmic history – from neighboring planets outside our solar system, known as exoplanets, to the most distant observable galaxies in the early universe.
