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- DictionaryMilk·y Way/ˌmilkē ˈwā/
- 1. a faint band of light crossing the sky, made up of vast numbers of faint stars. It corresponds to the plane of our Galaxy, in which most of its stars are located.
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What is Milky Way galaxy?
Why is Earth called the Milky Way?
What is the Milky Way really like?
Is the Milky Way a spiral galaxy?
The meaning of MILKY WAY is a broad luminous irregular band of light that stretches completely around the celestial sphere and is caused by the light of myriads of faint stars.
- Overview
- Star clusters and stellar associations
- Emission nebulae
- Planetary nebulae
- Supernova remnants
The Milky Way Galaxy takes its name from the Milky Way, the irregular luminous band of stars and gas clouds that stretches across the sky as seen from Earth.
How big is the Milky Way Galaxy?
The first reliable measurement of the size of the Milky Way Galaxy was made in 1917 by American astronomer Harlow Shapley. Assuming that the globular clusters outlined the Galaxy, he determined that it has a diameter of about 100,000 light-years. His values have held up remarkably well over the years.
Is Earth in the centre of the Milky Way Galaxy?
The solar system is about 30,000 light-years from the centre of the Milky Way Galaxy. The Galaxy itself is thought to be about 100,000 light-years in diameter.
Milky Way Galaxy, large spiral system consisting of several hundred billion stars, one of which is the Sun. It takes its name from the Milky Way, the irregular luminous band of stars and gas clouds that stretches across the sky as seen from Earth. Although Earth lies well within the Milky Way Galaxy (sometimes simply called the Galaxy), astronomers do not have as complete an understanding of its nature as they do of some external star systems. A thick layer of interstellar dust obscures much of the Galaxy from scrutiny by optical telescopes, and astronomers can determine its large-scale structure only with the aid of radio and infrared telescopes, which can detect the forms of radiation that penetrate the obscuring matter.
Although most stars in the Galaxy exist either as single stars like the Sun or as double stars, there are many conspicuous groups and clusters of stars that contain tens to thousands of members. These objects can be subdivided into three types: globular clusters, open clusters, and stellar associations. They differ primarily in age and in the numbe...
A conspicuous component of the Galaxy is the collection of large, bright, diffuse gaseous objects generally called nebulae. The brightest of these cloudlike objects are the emission nebulae, large complexes of interstellar gas and stars in which the gas exists in an ionized and excited state (with the electrons of the atoms excited to a higher than normal energy level). This condition is produced by the strong ultraviolet light emitted from the very luminous, hot stars embedded in the gas. Because emission nebulae consist almost entirely of ionized hydrogen, they are usually referred to as H II regions.
H II regions are found in the plane of the Galaxy intermixed with young stars, stellar associations, and the youngest of the open clusters. They are areas where very massive stars have recently formed, and many contain the uncondensed gas, dust, and molecular complexes commonly associated with ongoing star formation. The H II regions are concentrated in the spiral arms of the Galaxy, though some exist between the arms. Many of them are found at intermediate distances from the centre of the Milky Way Galaxy, with the largest number occurring at a distance of 10,000 light-years. This latter fact can be ascertained even though the H II regions cannot be seen clearly beyond a few thousand light-years from the Sun. They emit radio radiation of a characteristic type, with a thermal spectrum that indicates that their temperatures are about 10,000 kelvins. This thermal radio radiation enables astronomers to map the distribution of H II regions in distant parts of the Galaxy.
The gaseous clouds known as planetary nebulae are only superficially similar to other types of nebulae. So called because the smaller varieties almost resemble planetary disks when viewed through a telescope, planetary nebulae represent a stage at the end of the stellar life cycle rather than one at the beginning. The distribution of such nebulae i...
Another type of nebulous object found in the Galaxy is the remnant of the gas blown out from an exploding star that forms a supernova. Occasionally these objects look something like planetary nebulae, as in the case of the Crab Nebula, but they differ from the latter in three ways: (1) the total mass of their gas (they involve a larger mass, essent...
Apr 18, 2023 · The Milky Way is a barred spiral galaxy around 13.6 billion years old with large pivoting arms stretching out across the cosmos. Milky Way quick facts: – Galaxy type: Barred spiral –...
noun. the diffuse band of light stretching across the night sky that consists of millions of faint stars, nebulae, etc, within our Galaxy. another name for the Galaxy. Milky Way. / mĭl ′ kē /. The spiral galaxy that contains our solar system. Made up of an estimated two hundred billion stars or more, it is seen from Earth as an irregular ...
Oct 8, 2019 · January 4, 2021. The Milky Way galaxy is an immense, flat, disk-shaped collection of gas, dust, and stars that spreads around 100.000 light-years across and is several thousand light-years thick. Key Facts & Summary. There are at least 100 billion galaxies in the universe, and the Milky Way is just one of them.
Nov 1, 2023 · It is a vast galaxy, a large system that includes stars, gas (predominantly hydrogen), dust and dark matter, all bound together by gravity. As we navigate through the cosmos, an intriguing enigma emerges: What is the Milky Way truly like? What is it composed of, and what is its shape?
The meaning of MILKY WAY GALAXY is the galaxy of which the sun and the solar system are a part and which contains the myriads of stars that create the light of the Milky Way.
