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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.
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]
In Meteorologica, Aristotle (384–322 BC) states that the Greek philosophers Anaxagoras (c. 500 –428 BC) and Democritus (460–370 BC) proposed that the Milky Way is the glow of stars not directly visible due to Earth's shadow, while other stars receive their light from the Sun, but have their glow obscured by solar rays. [72]
A composite image of Earth, with its different types of surface discernible: Earth's surface dominating Ocean (blue), Africa with lush (green) to dry (brown) land and Earth's polar ice in the form of Antarctic sea ice (grey) covering the Antarctic or Southern Ocean and the Antarctic ice sheet (white) covering Antarctica.
The Moon's tidal lock to Earth results in the Moon's always showing only one side to Earth (see animated image). If Earth were flat, with the Moon hovering above it, then the portion of the Moon's surface visible to people on Earth would vary according to location on Earth, rather than showing an identical "face side" to everyone.
There are 293 confirmed moons in our cosmic neighborhood. By studying these worlds, astronomers hope to learn about ancient asteroid collisions, space volcanoes, and the origins of life itself.
Some 4.5 billion years ago, when Earth was only 100 million years old or so, a Mars-sized protoplanet named Theia smashed into our planet, ejecting loads that eventually returned to the Earth’s ...
The poles of astronomical bodies are determined based on their axis of rotation in relation to the celestial poles of the celestial sphere. Astronomical bodies include stars, planets, dwarf planets and small Solar System bodies such as comets and minor planets (e.g., asteroids), as well as natural satellites and minor-planet moons.