Search results
Results from the WOW.Com Content Network
Deep space is defined by the United States government as all of outer space which lies further from Earth than a typical low-Earth-orbit, thus assigning the Moon to deep-space. [118] Other definitions vary the starting point of deep-space from, "That which lies beyond the orbit of the moon," to "That which lies beyond the farthest reaches of ...
Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the Timaeus of Plato, or Socrates in his reflections on what the Greeks called khôra (i.e. "space"), or in the Physics of Aristotle (Book IV, Delta) in the definition of topos (i.e. place), or in the later "geometrical conception of place" as "space qua extension" in the ...
The physical universe is defined as all of space and time [a] (collectively referred to as spacetime) and their contents. [10] Such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, and therefore planets, moons, stars, galaxies, and the contents of intergalactic space.
Expansion of space accelerates and at some point becomes so extreme that even subatomic particles and the fabric of spacetime are pulled apart and unable to exist. For any value of the dark energy content of the universe where the negative pressure ratio is less than −1, the expansion rate of the universe will continue to increase without limit.
Absolute space acts on physical objects by inducing their resistance to acceleration but it cannot be acted upon. Newton himself recognized the role of inertial frames. [11] The motions of bodies included in a given space are the same among themselves, whether that space is at rest or moves uniformly forward in a straight line.
Commonly used calculations and limits for explaining gravitational collapse are usually based upon objects of relatively constant size, such as stars, and do not apply to rapidly expanding space such as the Big Bang. The observed fact that the early universe did not immediately collapse provides evidence for non-standard physics. [24]
The initial singularity is a singularity predicted by some models of the Big Bang theory to have existed before the Big Bang. [1] The instant immediately following the initial singularity is part of the Planck epoch, the earliest period of time in the history of our universe.
Its successor, the International Space Station, has maintained a continuous human presence in space since 2001. In 2004, U.S. President George W. Bush announced the Vision for Space Exploration, which called for a replacement for the aging Shuttle, a return to the Moon and, ultimately, a crewed mission to Mars.