Given our position within it, it is perhaps surprising that the formation of the Milky Way is still an active area of investigation. The different stellar components of the Milky Way are believed to have formed at different times with star formation still occuring in the thin disk , and evidence for all three of the currently recognised galaxy formation mechanisms primordial collapse, hierarchical clustering and secular evolution is present.
Like most galaxies, the Milky Way does not exist in isolation. Along with the Andromeda galaxy , the Large and Small Magellanic Clouds and approximately 30 dwarf galaxies , it forms part of the Local Group. The Milky Way is currently undergoing minor mergers with at least two of the Local Group dwarf galaxies — the Sagittarius and Canis Major dwarfs — and resides in the periphery of the great Virgo cluster with which it will also one day merge.
Black holes are born when a giant star runs out of energy. The star implodes, causing an explosion called a supernova. Scientists suspect a black hole lurks at the center of most galaxies. Those people live far from city lights that block out stars. All rights reserved.
Personality Quizzes. Funny Fill-In. Amazing Animals. Weird But True! Party Animals. Our Sun a star and all the planets around it are part of a galaxy known as the Milky Way Galaxy. A galaxy is a large group of stars, gas, and dust bound together by gravity. They come in a variety of shapes and sizes. The Milky Way is a large barred spiral galaxy. All the stars we see in the night sky are in our own Milky Way Galaxy.
Our galaxy is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area. It is very difficult to count the number of stars in the Milky Way from our position inside the galaxy.
Our best estimates tell us that the Milky Way is made up of approximately billion stars. These stars form a large disk whose diameter is about , light years. Our Solar System is about 25, light years away from the center of our galaxy — we live in the suburbs of our galaxy.
Most galaxies are thought to have a black hole in their heart. The bulge and the arms are the most obvious components of the Milky Way, but they are not the only pieces. The galaxy is surrounded by a spherical halo of hot gas, old stars and globular clusters. Although the halo stretches for hundreds of thousands of light-years, it only contains about two percent as many stars as are found within the disk. Scientists can't directly detect the material, but like black holes, they can measure it based on its effect on the objects around it.
As such, dark matter is estimated to make up 90 percent of the mass of the galaxy. Recent measurements have weighed the galaxy at between billion and billion times the mass of the sun.
By focusing on how the Milky Way affects its neighboring globular clusters, dense groups of stars smaller than a galaxy, scientists were able to calculate the mass of the Milky Way at varying distances.
The result can help them improve their understanding of how much of the galaxy is made up of ordinary material like dust and stars, and how much is composed of dark matter. The Milky Way contains over billion stars , and enough dust and gas to make billions more. The solar system lies about 30, light-years from the galactic center, and about 20 light-years above the plane of the galaxy.
Earth and its neighbors don't orbit within the plane of the galaxy but are instead tipped by about 63 degrees. More than half the stars found in the Milky Way are older than the 4. Galaxies like ours typically undergo a stellar baby boom , churning out stars in enormous quantities roughly 10 billion years ago. The most common stars in the galaxy are red dwarfs, a cool star about a tenth the mass of the sun.
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