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The so- called outer space and outer space is the entire space beyond the limits of a planet's atmosphere. Outer space is, in a first approximation, empty . However, it is not completely devoid of content, but is filled with extremely low pressure gases and powders. Outer space contains gravitational fields, electromagnetic radiation, neutrinos . Theoretically, it also contains black energy and dark matter . Because the atmosphere does not end abruptly, but becomes progressively thinner, there is no clearly defined boundary between the atmosphere and outer space.
In 350 BC. , Greek philosopher Aristotle suggested that nature abhors a vacuum , a principle which has become known as the horror vacui [1] . Based on this idea that the vacuum could not exist, for centuries it was believed that space could not be empty. [2] It was not until the 17th century that the French philosopher René Descartes argued that the entire space should be full. [3] Future research on vacuum physics was conducted by Otto von Guericke .
The outer space is closest to the perfect vacuum state . Effectively in this space there are no frictional forces, it allows stars, planets and satellites to move freely along their ideal gravitational trajectories. However, even in the most pronounced vacuum in intergalactic space there are still a few hydrogen atoms per cubic meter. [4] For comparison, the air we breathe contains about 10 25 molecules per cubic meter. Advanced space vacuum can be an attractive environment for certain industrial processes, such as those that require ultra-clean surfaces. [5]
The entire observable universe is filled with photons that were created during the Big Bang , known as cosmic microwave background radiation (CMBR). The large number of neutrinos causes cosmic background radiation with neutrinos. The current temperature of dark bodies (of this photon radiation) is 3 K (−270 ° C ; −454 ° F ). Some regions of outer space may contain particles with a high energy charge and have a much higher temperature than the cosmic background radiation CMBR.
Extraterrestrial space is not subject to the sovereignty of any state.
To perform an orbital spacecraft , a spacecraft must exceed its suborbital flight speed. A spacecraft does not enter orbit until it is moving at a sufficiently high speed so that its acceleration is less than or equal to the centripetal acceleration caused by its speed in circular motion. So in order to enter orbit, a spacecraft must not only reach that space, but must also reach a sufficient orbital speed. To pass into the low orbit of the Eartha ship must reach a speed of 7,900 m / s (28,400 km / h or 17,700 mph), for comparison the fastest aircraft ever reached a speed of 2,200 m / s (7,900 km / h or 4,900 mph) (in 1967 , North American aircraft X-15 ). [6]
Geospace is the region of outer space near Earth. Geospace includes the upper region of the atmosphere, as well as the ionosphere and magnetosphere . The Van Allen radiation belt is also within the geospatial. The region between the Earth's atmosphere and the Moon is sometimes called the cis-lunar space [7] .
Interplanetary space, the space around the Sun and solar system planets, interplanetary medium is dominated region that extends to the heliopause, until galactic environment where influence is stronger than the magnetic field and the flow of particles generated by the sun .
Interstellar space is the physical space in a galaxy that is not occupied by stars or their planetary systems. The interstellar medium refers - by definition - to the interstellar space (between stars).
Intergalactic space is the physical space between galaxies. It is generally free of dust and matter. Intergalactic space is very close to a total vacuum. The space between the galaxies, called void , is probably almost empty. Some theories estimate the average density of the universe to be the equivalent of one hydrogen atom per cubic meter. [8] [9]
The density of the universe, however, is not clearly uniform; this is between a relatively high density in galaxies (including very high density in celestial bodies in galaxies, such as planets, stars, and black holes ) and in the vastness of space, called void , the density is much lower than the universe average.
Based on two studies published in the Astrophysical Journal [10] [11] , physicist Christopher Martin claims to have obtained images of the intergalactic environment that is made up of gases and forms about 3% of the mass of the universe .
