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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. Tyrian purple - Wikipedia

    en.wikipedia.org/wiki/Tyrian_purple

    Tyrian purple is a pigment made from the mucus of several species of Murex snail. Production of Tyrian purple for use as a fabric dye began as early as 1200 BC by the Phoenicians, and was continued by the Greeks and Romans until 1453 AD, with the fall of Constantinople.

  4. Iridium - Wikipedia

    en.wikipedia.org/wiki/Iridium

    Iridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of 22.56 g/cm 3 (0.815 lb/cu in) [8] as defined by experimental X-ray crystallography. [a] 191 Ir and 193 Ir ...

  5. Porphyry (geology) - Wikipedia

    en.wikipedia.org/wiki/Porphyry_(geology)

    Porphyry (geology) Porphyry (/ ˈpɔːrfəri / POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate -rich, generally aphanitic matrix or groundmass. In its non-geologic, traditional use, the term porphyry usually refers to the purple-red form of ...

  6. List of flags containing the color purple - Wikipedia

    en.wikipedia.org/wiki/List_of_flags_containing...

    Purple is one of the least used colors in vexillology and heraldry. Currently, the color appears in only five national flags: that of Dominica, Spain, El Salvador, Nicaragua, and Mexico, and one co-official national flag, the Wiphala (co-official national flag of Bolivia). However, it is also present in the flags of several administrative ...

  7. Violet (color) - Wikipedia

    en.wikipedia.org/wiki/Violet_(color)

    In the 18th century, purple was a color worn by royalty, aristocrats and other wealthy people. Good-quality purple fabric was too expensive for ordinary people. The first cobalt violet, the intensely red-violet cobalt arsenate, was highly toxic. Although it persisted in some paint lines into the 20th century, it was displaced by less toxic ...

  8. Purple - Wikipedia

    en.wikipedia.org/wiki/Purple

    Purple has long been associated with royalty, originally because Tyrian purple dye—made from the secretions of sea snails—was extremely expensive in antiquity. [1] Purple was the color worn by Roman magistrates; it became the imperial color worn by the rulers of the Byzantine Empire and the Holy Roman Empire , and later by Roman Catholic ...

  9. Invader Zim - Wikipedia

    en.wikipedia.org/wiki/Invader_Zim

    —Tim Jones from The Daily Collegian Screen Rant ' s Spencer Coriaty wrote: "Backed by some of the most cutting edge animation at the time, and still breathtaking by today's standards, Invader Zim is like a Mystery Science Theater fan's dream come true. It seamlessly blends sci-fi, action and comedy into one twisted and hilarious cartoon with superb voice acting and visionary direction ...