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  2. N44 (emission nebula) - Wikipedia

    en.wikipedia.org/wiki/N44_(emission_nebula)

    N44 is classified as an emission nebula because it contains large regions of ionized hydrogen. However, the three strongest emission lines in the nebula are singly ionized oxygen atoms, which emit at an ultraviolet wavelength of 372.7 nm , doubly-ionized oxygen atoms, which emit at a blue-green wavelength of 500.7 nm, and neutral hydrogen atoms ...

  3. Emission nebula - Wikipedia

    en.wikipedia.org/wiki/Emission_nebula

    The nebula's color depends on its chemical composition and degree of ionization. Due to the prevalence of hydrogen in interstellar gas, and its relatively low energy of ionization, many emission nebulae appear red due to strong emissions of the Balmer series. If more energy is available, other elements will be ionized, and green and blue ...

  4. Boomerang Nebula - Wikipedia

    en.wikipedia.org/wiki/Boomerang_Nebula

    The Boomerang Nebula is a protoplanetary nebula [2] located 5,000 light-years from Earth in the constellation Centaurus. It is also known as the Bow Tie Nebula and catalogued as LEDA 3074547. [ 3 ] The nebula's temperature is measured at 1 K (−272.15 °C ; −457.87 °F ) making it the coolest natural place currently known in the Universe .

  5. Nebula - Wikipedia

    en.wikipedia.org/wiki/Nebula

    A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. [6] The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. [7]

  6. NGC 281 - Wikipedia

    en.wikipedia.org/wiki/NGC_281

    IC 11, Sh2-184, [3] Sharpless 184, [1] LBN 616, LBN 123.17-06.28, Pacman Nebula See also: Lists of nebulae NGC 281 , IC 11 or Sh2-184 is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way 's Perseus Spiral Arm .

  7. Atmosphere of Earth - Wikipedia

    en.wikipedia.org/wiki/Atmosphere_of_Earth

    Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation, although very tall cumulonimbus thunder clouds can penetrate the tropopause from below and rise into the ...

  8. NASA releases 'unprecedented' Horsehead Nebula image ... - AOL

    www.aol.com/news/nasa-releases-unprecedented...

    The image of the Horsehead Nebula captures the iconic nebula in a whole new light. NASA releases 'unprecedented' Horsehead Nebula image captured by James Webb Space Telescope. What to know about ...

  9. Strömgren sphere - Wikipedia

    en.wikipedia.org/wiki/Strömgren_sphere

    A very small amount of hydrogen atoms appear at a density that increases nearly exponentially toward the surface. Outside the sphere, radiation of the atoms' frequencies cools the gas strongly, so that it appears as a thin region in which the radiation emitted by the star is strongly absorbed by the atoms which lose their energy by radiation in ...