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  2. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    Sunlight on the surface of Earth is attenuated by Earth's atmosphere, so that less power arrives at the surface (closer to 1,000 W/m 2) in clear conditions when the Sun is near the zenith. [100] Sunlight at the top of Earth's atmosphere is composed (by total energy) of about 50% infrared light, 40% visible light, and 10% ultraviolet light. [ 101 ]

  3. Faint young Sun paradox - Wikipedia

    en.wikipedia.org/wiki/Faint_young_Sun_paradox

    The faint young Sun paradox or faint young Sun problem describes the apparent contradiction between observations of liquid water early in Earth's history and the astrophysical expectation that the Sun's output would have been only 70 percent as intense during that epoch as it is during the modern epoch. [1]

  4. Solar core - Wikipedia

    en.wikipedia.org/wiki/Solar_core

    The composition of the Sun varies with depth. In the photosphere, it is about 73–74% hydrogen by mass, the rest being primarily helium, which is the same composition as the atmosphere of Jupiter, and the primordial composition of gases at the earliest star formation after the Big Bang. However, as depth into the Sun increases, fusion ...

  5. Atmosphere of Earth - Wikipedia

    en.wikipedia.org/wiki/Atmosphere_of_Earth

    The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weather features such as clouds and hazes), all retained by Earth's gravity. The atmosphere serves as a ...

  6. Paleoatmosphere - Wikipedia

    en.wikipedia.org/wiki/Paleoatmosphere

    A paleoatmosphere (or palaeoatmosphere) is an atmosphere, particularly that of Earth, at some unspecified time in the geological past.. When regarding geological history of Earth, the paleoatmosphere can be chronologically divided into the Hadean first atmosphere, which resembled the compositions of the solar nebula; the Archean second atmosphere (also known as the prebiotic atmosphere), which ...

  7. Formation and evolution of the Solar System - Wikipedia

    en.wikipedia.org/wiki/Formation_and_evolution_of...

    Earth's fate is less clear; although the Sun will envelop Earth's current orbit, the star's loss of mass (and thus weaker gravity) will cause the planets' orbits to move farther out. [118] If it were only for this, Venus and Earth would probably escape incineration, [ 123 ] but a 2008 study suggests that Earth will likely be swallowed up as a ...

  8. Solar activity and climate - Wikipedia

    en.wikipedia.org/wiki/Solar_activity_and_climate

    Hypothesized solutions to this paradox include a vastly different atmosphere, with much higher concentrations of greenhouse gases than currently exist. [10] Over the following approximately 4 billion years, the Sun's energy output increased and the composition of the Earth atmosphere changed.

  9. Atmosphere - Wikipedia

    en.wikipedia.org/wiki/Atmosphere

    The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, solar wind, and cosmic rays and thus protects the organisms from genetic damage. The current composition of the atmosphere of the Earth is the product of billions of years of biochemical modification of the paleoatmosphere by living ...