Astronomy

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" Planetary astronomers (also called planetary scientists) focus on the growth, evolution, and death of planets. While most study the worlds inside the solar system, some use the growing body of evidence about planets around other stars to hypothesize what they might be like. According to the University College London, planetary science ""is a cross-discipline field including aspects of astronomy, atmospheric science, geology, space physics, biology and chemistry."" Stellar astronomers turn their eyes to the stars, including the black holes, nebulae, white dwarfs and supernova that survive stellar deaths. The University of California, Los Angeles, says, ""The focus of stellar astronomy is on the physical and chemical processes that occur in the universe."" Solar astronomers spend their time analyzing a single star — our sun. According to NASA, ""The quantity and quality of light from the sun varies on time scales from milli-seconds to billions of years."" Understanding those changes can help scientists recognize how Earth is affected. The sun also helps us to understand how other stars work, as it is the only star close enough to reveal details about its surface. Galactic astronomers study our galaxy, the Milky Way, while extragalactic astronomers peer outside of it to determine how these collections of stars form, change, and die. The University of Wisconsin-Madison says, ""Establishing patterns in the distribution, composition, and physical conditions of stars and gas traces the history of our evolving home galaxy."" Cosmologists focus on the universe in its entirety, from its violent birth in the Big Bang to its present evolution, all the way to its eventual death. Astronomy is often (not always) about very concrete, observable things, whereas cosmology typically involves large-scale properties of the universe and esoteric, invisible and sometimes purely theoretical things like string theory, dark matter and dark energy, and the notion of multiple universes."