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  2. Origin of water on Earth - Wikipedia

    en.wikipedia.org/wiki/Origin_of_water_on_Earth

    The deuterium to hydrogen ratio for ocean water on Earth is known very precisely to be (1.5576 ± 0.0005) × 10 −4. [36] This value represents a mixture of all of the sources that contributed to Earth's reservoirs, and is used to identify the source or sources of Earth's water.

  3. Greenhouse gas - Wikipedia

    en.wikipedia.org/wiki/Greenhouse_gas

    This is an accepted version of this page This is the latest accepted revision, reviewed on 13 February 2025. Gas in an atmosphere with certain absorption characteristics This article is about the physical properties of greenhouse gases. For how human activities are adding to greenhouse gases, see Greenhouse gas emissions. Greenhouse gases trap some of the heat that results when sunlight heats ...

  4. 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.

  5. Gas exchange - Wikipedia

    en.wikipedia.org/wiki/Gas_exchange

    Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.

  6. Water - Wikipedia

    en.wikipedia.org/wiki/Water

    One factor in estimating when water appeared on Earth is that water is continually being lost to space. H 2 O molecules in the atmosphere are broken up by photolysis, and the resulting free hydrogen atoms can sometimes escape Earth's gravitational pull. When the Earth was younger and less massive, water would have been lost to space more easily.

  7. Carbon sink - Wikipedia

    en.wikipedia.org/wiki/Carbon_sink

    Since the 1850s, there are more carbon sources than sinks and therefore the carbon dioxide in Earth's atmosphere is rising. [1] A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere".

  8. BBC Bitesize - Wikipedia

    en.wikipedia.org/wiki/BBC_Bitesize

    GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.

  9. Greenhouse effect - Wikipedia

    en.wikipedia.org/wiki/Greenhouse_effect

    The greenhouse effect on Earth is defined as: "The infrared radiative effect of all infrared absorbing constituents in the atmosphere.Greenhouse gases (GHGs), clouds, and some aerosols absorb terrestrial radiation emitted by the Earth's surface and elsewhere in the atmosphere."