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18947847. LC Class. PZ7.L9673 Nu 1989. Number the Stars is a work of historical fiction by the American author Lois Lowry about the escape of a family of Jews from Copenhagen, Denmark, during World War II. The story revolves around ten-year-old Annemarie Johansen, who lives with her mother, father, and sister Kirsti in Copenhagen in 1943.
The first generation of stars, known as Population III stars, formed within a few hundred million years after the Big Bang. [57] 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.
5th century BC — Democritus proposes that the bright band in the night sky known as the Milky Way might consist of stars. 4th century BC — Aristotle believes the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together" and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which ...
830 CE. [] The first major Arabic work of astronomy is the Zij al-Sindh by Muhammad ibn Musa al-Khwarizmi. The work contains tables for the movements of the Sun, the Moon, and the five planets known at the time. The work is significant as it introduced Ptolemaic concepts into Islamic sciences. This work also marks the turning point in Arabic ...
The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery (multiple dates occur when the moments of imaging, observation, and publication differ), identified through its various designations (including temporary and permanent schemes), and the ...
By comparing the spectra of stars such as Sirius to the Sun, they found differences in the strength and number of their absorption lines—the dark lines in stellar spectra caused by the atmosphere's absorption of specific frequencies. In 1865, Secchi began classifying stars into spectral types. [95]
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
The timeline of the early universe outlines the formation and subsequent evolution of the Universe from the Big Bang (13.799 ± 0.021 billion years ago) [1] to the present day. An epoch is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new era or age. Times on this list are measured ...