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  2. Sheldon coin grading scale - Wikipedia

    en.wikipedia.org/wiki/Sheldon_coin_grading_scale

    Coin dealers will normally grade these coins at or below the ones shown for that respective type, the grades here depend on how bad the issue or issues are. [27] Grading services typically label these coins as "authentic" with x grade "details" (ex: "EF details"). Coins that are uncirculated as mentioned above can not go below an MS-60 grade.

  3. Coin grading - Wikipedia

    en.wikipedia.org/wiki/Coin_grading

    Coin grading [1] is the process of determining the grade or condition of a coin, one of the key factors in determining its collectible value. A coin's grade is generally determined by six criteria: strike, preservation, luster, color, attractiveness, and occasionally the country/state in which it was minted. Several grading systems have been ...

  4. Photon epoch - Wikipedia

    en.wikipedia.org/wiki/Photon_epoch

    In physical cosmology, the photon epoch was the period in the evolution of the early universe in which photons dominated the energy of the universe. The photon epoch started after most leptons and anti-leptons were annihilated at the end of the lepton epoch, about 10 seconds after the Big Bang. [1]

  5. Cosmological decade - Wikipedia

    en.wikipedia.org/wiki/Cosmological_decade

    The epoch CÐ −43.2683 was 10 (−43.2683) seconds, which represents the Planck time since the Big Bang (Time Zero). There were an infinite number of cosmological decades between the Big Bang and the Planck epoch (or any other point in time). The current epoch, CÐ 17.6389, is 10 (17.6389) seconds, or 13.799(21) billion years, since the Big ...

  6. Numismatic Guaranty Company - Wikipedia

    en.wikipedia.org/wiki/Numismatic_Guaranty_Company

    The NGC grading scale is based on the 70-point Sheldon coin grading scale. Strike designations include Prooflike and Deep Prooflike for circulation issue coins and Cameo and Ultra Cameo for Proof coins. Coins deemed high-end for their particular numeric grade receive a "Plus" designation. Coins considered attractive get a "Star" moniker.

  7. Quark epoch - Wikipedia

    en.wikipedia.org/wiki/Quark_epoch

    A visual representation of the division order of universal forces. In physical cosmology, the quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but the temperature of the universe was still too high to allow quarks to bind together ...

  8. Category:Coin grading - Wikipedia

    en.wikipedia.org/wiki/Category:Coin_grading

    Sheldon coin grading scale; T. Third-party grading; V. VAM (Morgan and Peace dollar die varieties) ... This page was last edited on 6 August 2023, at 10:21 (UTC).

  9. Recombination (cosmology) - Wikipedia

    en.wikipedia.org/wiki/Recombination_(cosmology)

    Recombination occurred about 378 000 years [1] after the Big Bang (at a redshift of z = 1100). [2] The word "recombination" is misleading, since the Big Bang theory does not posit that protons and electrons had been combined before, but the name exists for historical reasons since it was named before the Big Bang hypothesis became the primary ...