On April 7, 2010, the Marshall Islands Postal Service issued five new stamps featuring some of history's early astronomers.
Wilhelm Hirschel systematically observed the heavens, compiling three catalogs listing thousands of nebulae and contributed pioneering ideas about the stellar system's structure.
Nicolaus Copernicus refuted Ptolemy's theory that the Earth was the center of the universe, revolutionizing human perception of the universe.
Galileo Galilei was the first to use a telescope to observe the heavens, demonstrating the Milky Way galaxy is composed of stars. He laid the groundwork for the unification of physics and astronomy.
Johannes Kepler, the founder of modern astronomy, showed the orbit of Mars is an ellipse, and established his three laws of planetary motion.
Isaac Newton invented the first reflecting telescope. His observations of the properties of sunlight later formed the basis of the spectrograph, allowing astronomers to determine a star's speed, direction and composition.