Local GroupThe Local Group is the galaxy group that includes the Milky Way, where Earth is located. It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellite galaxies form one lobe, and the Andromeda Galaxy and its satellite galaxies constitute the other.
Dwarf spheroidal galaxyA dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and as systems that are companions to the Andromeda Galaxy (M31).
Satellite galaxyA satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents are bound to their host galaxy, in the same way that planets within the Solar System are gravitationally bound to the Sun. While most satellite galaxies are dwarf galaxies, satellite galaxies of large galaxy clusters can be much more massive.
Dark matterHypothetical invisible cosmic materialUnsolved problem in physicsWhat is dark matter?
Milky WayGalaxy containing the Solar SystemArtist's impression of the structure of the Milky Way based on data from the European Space Agency's Gaia telescope, including the location of the spiral arms, bar, and bulgeThe Milky Way or Milky Way Galaxy, or simply the Galaxy, is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye.
Draco (constellation)Draco is a constellation in the far northern sky. Its name is derived from the Latin word for dragon. It was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and remains one of the 88 modern constellations today. The north pole of the ecliptic is in Draco. Draco is circumpolar from northern latitudes, meaning that it never sets and can be seen at any time of year.
Lowell ObservatoryLowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965. In 2011, the Observatory was named one of "The World's 100 Most Important Places" by Time magazine. It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh.
Albert George WilsonAlbert George Wilson (July 28, 1918 – August 27, 2012) was an American astronomer and a discoverer of minor planets. He was born in Houston, Texas. He received his Ph.D. in mathematics from Caltech in 1947; his thesis title was Axially Symmetric Thermal Stresses in a Semi-Infinite Solid advised by Harry Bateman. In 1949, he accepted a job at Palomar Observatory, and led the Palomar Sky Survey.
Galactic planeThe galactic plane is the plane on which most of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms galactic plane and galactic poles usually refer specifically to the plane and poles of the Milky Way, in which planet Earth is located. Some galaxies are irregular and do not have any well-defined disk.
ConstellationA constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellations were likely defined in prehistory. People used them to relate stories of their beliefs, experiences, creation, and mythology.
National Geographic SocietyThe National Geographic Society, headquartered in Washington, D.C., United States, is one of the largest nonprofit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, natural science, the promotion of environmental and historicalconservation, and the study of world culture and history.National Geographic Society – Palomar Observatory Sky SurveyThe National Geographic Society – Palomar Observatory Sky Survey (NGS-POSS, or just POSS, also POSS I) was a major astronomical survey, that took almost 2,000 photographic plates of the night sky. It was conducted at Palomar Observatory, California, United States, and completed by the end of 1958.*As an Amazon Associate I earn from qualifying purchases.