The Local Group is the cluster of galaxies to which we belong. It is a group of about 30 galaxies that is about 5 million light-years across. The largest of the galaxies are Andromeda galaxy , Triangulum, and our Milky Way . The Local Group also includes Fornax, the Large and Small Magellanic Clouds, M32, M33, M101, and 9 dwarf spheroidal galaxies. The center of the Local Group is roughly between the Milky Way and the Andromeda Galaxy, M31.
Longitude is the angular distance east or west of the prime meridian of a celestial object.
A long period comet has an orbital period over 200 years. This type of comet may originate from the Oort cloud . These satellites orbit the Earth in about 90 minutes. Lowell studied Mars extensively, especially its surface markings, which he thought were canals. Lowell also calculated that an unknown planet, dubbed Planet X, must orbit beyond Neptune .