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  2. Purple Earth hypothesis - Wikipedia

    en.wikipedia.org/wiki/Purple_Earth_hypothesis

    The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis, first proposed by molecular biologist Shiladitya DasSarma in 2007, [1] that the earliest photosynthetic life forms of Early Earth were based on the simpler molecule retinal rather than the more complex porphyrin-based chlorophyll, making the surface biosphere appear purplish ...

  3. Timeline of first images of Earth from space - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_first_images...

    First image, color images and movie of Earth from space taken by a person, by cosmonaut Gherman Titov – the first photographer from space. [25] [26] 1963 KH-7 Gambit: First high-resolution (sub-meter spatial resolution) satellite photography (classified). [27] 1964 Quill: First radar images of Earth from space, using a synthetic aperture ...

  4. Color theory - Wikipedia

    en.wikipedia.org/wiki/Color_theory

    Color theory, or more specifically traditional color theory, is a historical body of knowledge describing the behavior of colors, namely in color mixing, color contrast effects, color harmony, color schemes and color symbolism. [1] Modern color theory is generally referred to as color science.

  5. Luminiferous aether - Wikipedia

    en.wikipedia.org/wiki/Luminiferous_aether

    In the 17th century, Robert Boyle was a proponent of an aether hypothesis. According to Boyle, the aether consists of subtle particles, one sort of which explains the absence of vacuum and the mechanical interactions between bodies, and the other sort of which explains phenomena such as magnetism (and possibly gravity) that are, otherwise, inexplicable on the basis of purely mechanical ...

  6. History of Earth - Wikipedia

    en.wikipedia.org/wiki/History_of_Earth

    The first eon in Earth's history, the Hadean, begins with Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of Earth's crust and Earth itself.

  7. The history and meaning behind Women's History Month colors

    www.aol.com/news/history-meaning-behind-womens...

    Here's the history and meaning behind Women's history month colors: purple, green, white and gold. Experts explain the fascinating origins.

  8. On Vision and Colours - Wikipedia

    en.wikipedia.org/wiki/On_Vision_and_Colours

    Likewise my theory alone gives the true sense in which the notion of complementary colours is to be taken, viz: as having no reference to light, but to the Retina, and not being a redintegration [restoration] of white light, but of the full action of the Retina, which by every colour undergoes a bipartition either in yellow (3/4) and violet (1/ ...

  9. Pale Blue Dot (book) - Wikipedia

    en.wikipedia.org/wiki/Pale_Blue_Dot_(book)

    The first part of the book examines the claims made throughout history that Earth and the human species are unique. Sagan proposes two reasons for the persistence of the idea of a geocentric, or Earth-centered universe: human pride in our existence, and the threat of torturing those who dissented from it, particularly during the time of the Roman Inquisition.