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A wide field view of outer space as seen from Earth's surface at night. The interplanetary dust cloud is visible as the horizontal band of zodiacal light, including the false dawn [29] (edges) and gegenschein (center), which is visually crossed by the Milky Way. Outer space is the closest known approximation to a perfect vacuum.
In such statements, "reaching the edge of space" merely refers to going higher than average aeronautical vehicles commonly would. [11] [12] There is still no international legal definition of the demarcation between a country's air space and outer space. [13] In 1963, Andrew G. Haley discussed the Kármán line in his book Space Law and ...
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 .
Outer space (or simply space) is the expanse that exists beyond Earth's atmosphere and between celestial bodies.It contains ultra-low levels of particle densities, constituting a near-perfect vacuum of predominantly hydrogen and helium plasma, permeated by electromagnetic radiation, cosmic rays, neutrinos, magnetic fields and dust.
This is a timeline of space exploration which includes notable achievements, first accomplishments and milestones in humanity's exploration of outer space. This timeline generally does not distinguish achievements by a specific country or private company, as it considers humanity as a whole.
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.
Its outer layers will be ejected into space, leaving behind a dense white dwarf, half the original mass of the Sun but only the size of Earth. [30] The ejected outer layers may form a planetary nebula, returning some of the material that formed the Sun—but now enriched with heavier elements like carbon—to the interstellar medium. [33] [34]