Sprawling across almost 200 light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Derived from its Valentine's-Day-approved shape, its nickname is the Heart Nebula. About 7,500 light-years away in the Perseus spiral arm of our galaxy, stars were born in IC 1805. In fact, near the cosmic heart's center are the massive hot stars of a newborn star cluster also known as Melotte 15, about 1.5 million years young.The nebula glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all created by a small group of stars near the nebula's center. In the center of the Heart Nebula are young stars from the open star cluster Melotte 15 that are eroding away several picturesque dust pillars with their energetic light and winds. The open cluster of stars contains a few bright stars nearly 50 times the mass of our Sun. The Heart Nebula is located about 7,500 light years away toward the constellation of Cassiopeia.
According to modern astronomers, the Orion Nebula is an enormous cloud of gas and dust, one of many in our Milky Way galaxy. It lies roughly 1,300 light-years from Earth.
At some 30 to 40 light-years in diameter, this great big nebulous cocoon is giving birth to perhaps a thousand stars. A young open star cluster, whose stars were born at the same time from a portion of the nebula and are still loosely bound by gravity, can be seen within the nebula. It is sometimes called the Orion Nebula Star Cluster. In 2012, an international team of astronomers suggested this cluster in the Orion Nebula might have a black hole at its heart.
The four brightest stars in the Orion Nebula can be seen through amateur astronomers’ telescopes and are affectionately known as The Trapezium. The light of the young, hot Trapezium stars illuminate the Orion Nebula. These stars are only a million or so years old – mere babies in the lifetime of a star.
The Pleiades, or Seven Sisters, is an open star cluster located in the constellation of Taurus. The cluster contains hundreds of stars, of which only a handful are commonly visible to the unaided eye. The cluster is dominated by hot blue and extremely luminous stars that are thought to have formed together around 100 million years ago, making them 1/50th the age of our sun.
It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. Dust that forms a faint reflection nebulosity around the brightest stars was thought at first to be left over from the formation of the cluster, but is now known to be an unrelated dust cloud in the interstellar medium, through which the stars are currently passing
The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 2.5 million light-years from Earth. It is the nearest major galaxy to the Milky Way and was often referred to as the Great Andromeda Nebula in older texts. It received its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda.
Andromeda is approximately 220,000 light years across, and it is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and other smaller galaxies. Despite earlier findings that suggested that the Milky Way contains more dark matter and could be the largest in the grouping, the 2006 observations by the Spitzer Space Telescope revealed that Andromeda contains one trillion stars, at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion.
The Milky Way and Andromeda galaxies are expected to collide in 4.5 billion years, eventually merging to form a giant elliptical galaxy or perhaps a large disc galaxy.The apparent magnitude of the Andromeda Galaxy, at 3.4, is among the brightest of the Messier objects, making it visible to the naked eye on moonless nights, even when viewed from areas with moderate light pollution.
In this image you'll see the Orion Nebula in the top right of the photo, a massive cloud of gas and dust around 1,300 light years from Earth, located in the constellation of Orion.
The Orion Nebula is a hive of star forming activity, as a result it has given us a greater understanding as to how stars are formed. Many stars in the Orion Nebula have disks of debris around them, indicating the very beginnings of planetary formation. The Orion Nebula contains the Trapezium star cluster, a tight group of young massive stars that provide much of the nebula's brightness.
At the bottom left is the Horsehead nebula and the Flame nebula, also known as NGC 2023 and NGC 2024. The Horsehead Nebula is a dark nebula in the constellation Orion, approximately 1500 light years from Earth. It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which bears some resemblance to a horse's head when viewed from Earth.