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    Timelines – Astronomy

    Inception of Astronomy (Ancient Times – 600 BC): Astronomy, the oldest of the natural sciences, started by simply observing natural celestial phenomena. In ancient civilizations such as the Sumerians, Babylonians, and Egyptians, people used primitive devices to note the motion of the stars and planets, creating complex lunar-based calendars.

    Greek Astronomy (600 BC – 150 AD): Thales of Miletus, the pioneer of Greek astronomy, reportedly predicted an eclipse in 585 BC. Hipparchus (c. 190–c. 120 BC) cataloged stars and developed a precise method for predicting solar eclipses. Claudius Ptolemy’s geocentric model (2nd century AD), listed in the ‘Almagest’, was the accepted standard for over a millennium.

    Islamic Golden Age (750 – 1250 AD): Arabic astronomers like Al-Battani, Al-Zarqali, and Al-Biruni advanced astronomical knowledge significantly. They improved Greek geometrical models and developed numerous observational and navigational instruments.

    Copernican Revolution (1500 – 1600 AD): Nicolas Copernicus (1473-1543) proposed the heliocentric model – portraying Earth and other planets revolving around the Sun. This marked a vital departure from previous geocentric models.

    First Telescopic Discoveries (1610 AD): Galileo Galilei pointed his telescope to the night sky for the first time. This led to major discoveries, including the four largest moons of Jupiter, phases of Venus, and the rugged terrain of the Moon.

    Newtonian Revolution (1687 AD): Englishman Sir Isaac Newton published the ‘Principia Mathematica,’ introducing the laws of motion and universal gravitation. His findings laid the foundation for classical mechanics, significantly impacting fields like astronomy and physics.

    The Spectroscope (1859 AD): German physicist Gustav Kirchhoff and chemist Robert Bunsen invented the spectroscope, an instrument used to separate light into a spectrum. They established the understanding of spectral lines, which led to the development of astronomical spectroscopy.

    Einstein’s Theory of Relativity (1915 AD): Albert Einstein’s theory of general relativity, published in 1915, significantly influenced the field of cosmology, explaining how massive objects cause a distortion in space-time, seen as gravity.

    Edwin Hubble’s Discoveries (1929 AD): Edwin Hubble demonstrated the universe was expanding, leading to the concept of the Big Bang theory. He also established a classification system for galaxies, later known as Hubble’s sequence.

    The Space Age (1957 – Present Day): In 1957, the Soviet Union launched the first artificial satellite, Sputnik 1, marking the start of space exploration. The Hubble Space Telescope, launched in 1990, has provided some of the most detailed images of distant galaxies, nebulae, and stars. The age of space telescopes like Chandra X-Ray Observatory, Spitzer Space Telescope, Kepler Space Telescope, and the latest James Webb Space Telescope has ushered in a new era for astronomy.