Physical Science:

The Andromeda Galaxy [Figure 14.1.1.(c)], also known as Messier 31 or M31, is a spiral galaxy located about 2.5 million light-years away from Earth in the constellation Andromeda. It is the closest spiral galaxy to our own Milky Way. The Andromeda Galaxy is about 220,000 light-years in diameter, making it almost twice as large as the Milky Way. It contains about a trillion stars, which is more than three times the number of stars in the Milky Way. Like the Milky Way, it has a central bulge and spiral arms that wrap around it.

The largest galaxy in the observable universe is believed to be IC 1101, which is located about 1.04 billion light-years away from Earth in the constellation Virgo. IC 1101 is a giant elliptical galaxy that is estimated to have a diameter of around 6 million light-years and contains trillions of stars. It is also one of the most massive galaxies known, with a mass estimated to be around 100 trillion times that of our Sun. However, it’s worth noting that our observations of the universe are limited by the distance and the capabilities of our telescopes, and there may be larger galaxies beyond our observable universe that we are unable to detect.