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  2. Space - Wikipedia

    en.wikipedia.org/wiki/Space

    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 ...

  3. Universe - Wikipedia

    en.wikipedia.org/wiki/Universe

    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.

  4. Space telescope - Wikipedia

    en.wikipedia.org/wiki/Space_telescope

    A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory , OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971.

  5. Outer space - Wikipedia

    en.wikipedia.org/wiki/Outer_space

    Being essentially empty, outer space allows the earliest (redder) galaxies to be viewed without obstruction, as in the Webb's First Deep Field image. Outer space (or simply space) is the expanse that exists beyond Earth's atmosphere and between celestial bodies. [1] It contains ultra-low levels of particle densities, constituting a near-perfect ...

  6. Shape of the universe - Wikipedia

    en.wikipedia.org/wiki/Shape_of_the_universe

    e. In physical cosmology, the shape of the universe refers to both its local and global geometry. Local geometry is defined primarily by its curvature, while the global geometry is characterised by its topology (which itself is constrained by curvature). General relativity explains how spatial curvature (local geometry) is constrained by gravity.

  7. Space exploration - Wikipedia

    en.wikipedia.org/wiki/Space_exploration

    t. e. Space exploration is the use of astronomy and space technology to explore outer space. [1] While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy ...

  8. Observable universe - Wikipedia

    en.wikipedia.org/wiki/Observable_universe

    Ordinary (baryonic) matter (4.9%) Dark matter (26.8%) Dark energy (68.3%) [ 6 ] 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 ...

  9. Astronomy - Wikipedia

    en.wikipedia.org/wiki/Astronomy

    Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets.