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  2. Timeline of Solar System astronomy - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_Solar_System...

    c. 560 BCE – Anaximander is arguably the first to conceive a mechanical model of the world, although highly inaccurate: a cylindrical Earth [11] floats freely in space surrounded by three concentric wheels turning at different distances: the closest for the stars and planets, the second for the Moon and the farthest for the Sun, all conceived ...

  3. Chronology of the universe - Wikipedia

    en.wikipedia.org/wiki/Chronology_of_the_universe

    The first generation of stars, known as Population III stars, formed within a few hundred million years after the Big Bang. [49] These stars were the first source of visible light in the universe after recombination. Structures may have begun to emerge from around 150 million years, and early galaxies emerged from around 180 to 700 million years.

  4. Stellar evolution - Wikipedia

    en.wikipedia.org/wiki/Stellar_evolution

    Representative lifetimes of stars as a function of their masses The change in size with time of a Sun-like star Artist's depiction of the life cycle of a Sun-like star, starting as a main-sequence star at lower left then expanding through the subgiant and giant phases, until its outer envelope is expelled to form a planetary nebula at upper right Chart of stellar evolution

  5. The Five Ages of the Universe - Wikipedia

    en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe

    The Stelliferous Era, is defined as, "6 < n < 14". This is the current era, in which matter is arranged in the form of stars, galaxies, and galaxy clusters, and most energy is produced in stars. Stars will be the most dominant objects of the universe in this era. Massive stars use up their fuel very rapidly, in as little as a few million years.

  6. Timeline of space exploration - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_space_exploration

    This is a timeline of space exploration which includes notable achievements, first accomplishments and milestones in humanity's exploration of outer space. This timeline generally does not distinguish achievements by a specific country or private company, as it considers humanity as a whole.

  7. Timeline of knowledge about galaxies, clusters of galaxies ...

    en.wikipedia.org/wiki/Timeline_of_knowledge...

    By 1781 the final published list grows to 103 objects, 34 of which turn out to be galaxies. 1785 – William Herschel carried the first attempt to describe the shape of the Milky Way and the position of the Sun in it by carefully counting the number of stars in different regions of the sky. He produced a diagram of the shape of the galaxy with ...

  8. Hypothetical star - Wikipedia

    en.wikipedia.org/wiki/Hypothetical_star

    The very earliest stars, virtually free of metals, believed to have existed in the early universe when the only common elements were primordial hydrogen and helium. none: Preon star: A star with a core composed of preons. none: Q star (grey hole) A compact, heavy neutron star with an exotic state of matter where most light does not escape the ...

  9. Q star - Wikipedia

    en.wikipedia.org/wiki/Q_star

    A Q-star, also known as a grey hole, is a hypothetical type of a compact, heavy neutron star with an exotic state of matter. Such a star can be smaller than the progenitor star's Schwarzschild radius and have a gravitational pull so strong that some light, but not all photons, can escape.