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From Earths surface to the top of the stratosphere (50 km) is just under 1% of Earth's radius. The mesosphere (/ ˈ m ɛ s ə s f ɪər, ˈ m ɛ z-, ˈ m iː s ə-,-z ə-/; [1] from Ancient Greek μέσος (mésos) 'middle' and -sphere) is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere.
A FASOR used at the Starfire Optical Range for LIDAR and laser guide star experiments is tuned to the sodium D2a line and used to excite sodium atoms in the upper atmosphere. (FASOR stands for Frequency Addition Source of Optical Radiation.) The sodium layer is a layer of neutral atoms of sodium within Earth's mesosphere.
The following is a list of stars with resolved images, that is, stars whose images have been resolved beyond a point source. Aside from the Sun , observed from Earth , stars are exceedingly small in apparent size, requiring the use of special high-resolution equipment and techniques to image.
So far, 131 such objects have been found. Only 22 are bright enough to be visible without a telescope, for which the star's visible light needs to reach or exceed the dimmest brightness visible to the naked eye from Earth, 6.5 apparent magnitude. [1] The known 131 objects are bound in 94 stellar systems.
A meteor or shooting star [8] is the visible passage of a meteoroid, comet, or asteroid entering Earth's atmosphere. At a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake.
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]
A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. [ 2 ]
Noctilucent clouds (NLCs), or night shining clouds, [1] are tenuous cloud-like phenomena in the upper atmosphere of Earth.When viewed from space, they are called polar mesospheric clouds (PMCs), detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause.