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  2. Mesosphere - Wikipedia

    en.wikipedia.org/wiki/Mesosphere

    The exact upper and lower boundaries of the mesosphere vary with latitude and with season (higher in winter and at the tropics, lower in summer and at the poles), but the lower boundary is usually located at altitudes from 47 to 51 km (29 to 32 mi; 154,000 to 167,000 ft) above sea level, and the upper boundary (the mesopause) is usually from 85 ...

  3. List of nearest stars - Wikipedia

    en.wikipedia.org/wiki/List_of_nearest_stars

    The closest encounter to the Sun so far predicted is the low-mass orange dwarf star Gliese 710 / HIP 89825 with roughly 60% the mass of the Sun. [4] It is currently predicted to pass 0.1696 ± 0.0065 ly (10 635 ± 500 au) from the Sun in 1.290 ± 0.04 million years from the present, close enough to significantly disturb the Solar System's Oort ...

  4. Lower mantle - Wikipedia

    en.wikipedia.org/wiki/Lower_mantle

    Structure of Earth. The mesosphere is labeled as Stiffer mantle in this diagram.. The lower mantle, historically also known as the mesosphere, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below Earth's surface; between the transition zone and the outer core. [1]

  5. Star chart - Wikipedia

    en.wikipedia.org/wiki/Star_chart

    An online star chart; Monthly sky maps for every location on Earth Archived 2007-09-13 at the Wayback Machine; The Evening Sky Map – Free monthly star charts and calendar for northern hemisphere, southern hemisphere, and equatorial sky watchers. Sky Map Online – Free interactive star chart (showing over 1.2 million stars up to magnitude 12)

  6. Poles of astronomical bodies - Wikipedia

    en.wikipedia.org/wiki/Poles_of_astronomical_bodies

    The location of the celestial poles of some selected Solar System objects is shown in the following table. [1] The coordinates are given relative to Earth's celestial equator and the vernal equinox as they existed at J2000 (2000 January 1 12:00:00 TT ) which is a plane fixed in inertial space now called the International Celestial Reference ...

  7. Timeline of astronomical maps, catalogs, and surveys

    en.wikipedia.org/wiki/Timeline_of_astronomical...

    c. 300 BC — star catalog of Timocharis of Alexandria; c. 134 BC — Hipparchus makes a detailed star map; c. 150 — Ptolemy completes his Almagest, which contains a catalog of stars, observations of planetary motions, and treatises on geometry and cosmology; c. 705 — Dunhuang Star Chart, a manuscript star chart from the Mogao Caves at Dunhuang

  8. List of nearest stars by spectral type - Wikipedia

    en.wikipedia.org/wiki/List_of_nearest_stars_by...

    Below there are lists the nearest stars separated by spectral type. The scope of the list is still restricted to the main sequence spectral types: M, K, F, G, A, B and O. It may be later expanded to other types, such as S, D or C. The Alpha Centauri star system is the closest star system to the Sun.

  9. Kármán line - Wikipedia

    en.wikipedia.org/wiki/Kármán_line

    Earth's atmosphere photographed from the International Space Station.The orange and green line of airglow is at roughly the altitude of the Kármán line. [1]The Kármán line (or von Kármán line / v ɒ n ˈ k ɑːr m ɑː n /) [2] is a conventional definition of the edge of space; it is widely but not universally accepted.