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Stars, dust, gas, black holes, dark matter...By far the most significant component, in terms of mass, is dark matter, making up about 80-90% of a galaxy's mass.
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What is the order in decreasing size of spiral giant elliptical dwarf elliptical and irregular galaxies?
Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence. Since the Hubble sequence is entirely based upon visual morphological type, it may miss certain important characteristics of galaxies such as star formation rate (in starburst galaxies) and activity in the core (in active galaxies).Elliptical galaxyThe Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead the galaxy is dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions. In this sense they have some similarity to the much smaller globular clusters.The largest galaxies are giant ellipticals. Many elliptical galaxies are believed to form due to the interaction of galaxies, resulting in a collision and merger. They can grow to enormous sizes (compared to spiral galaxies, for example), and giant elliptical galaxies are often found near the core of large galaxy clusters.Starburst galaxies are the result of such a galactic collision that can result in the formation of an elliptical galaxy.Spiral galaxy and Barred spiral galaxyThe Sombrero Galaxy, an example of an unbarred spiral galaxy. Credit:Hubble Space Telescope/NASA/ESA.Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge. An Sa galaxy has tightly wound, poorly-defined arms and possesses a relatively large core region. At the other extreme, an Sc galaxy has open, well-defined arms and a small core region.In spiral galaxies, the spiral arms have the shape of approximate logarithmic spirals, a pattern that can be theoretically shown to result from a disturbance in a uniformly rotating mass of stars. Like the stars, the spiral arms also rotate around the center, but they do so with constant angular velocity. That means that stars pass in and out of spiral arms, with stars near the galactic core orbiting faster than the arms are moving while stars near the outer parts of the galaxy typically orbit more slowly than the arms. The spiral arms are thought to be areas of high density matter, or "density waves". As stars move through an arm, the space velocity of each stellar system is modified by the gravitational force of the higher density. (The velocity returns to normal after the stars depart on the other side of the arm.) This effect is akin to a "wave" of slowdowns moving along a highway full of moving cars. The arms are visible because the high density facilitates star formation, and therefore they harbor many bright and young stars.NGC 1300, an example of a barred spiral galaxy. Credit:Hubble Space Telescope/NASA/ESA.A majority of spiral galaxies have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). Bars are thought to be temporary structures that can occur as a result of a density wave radiating outward from the core, or else due to a tidal interaction with another galaxy. Many barred spiral galaxies are active, possibly as a result of gas being channeled into the core along the arms.Our own galaxy is a large disk-shaped barred-spiral galaxy about 30 kiloparsecs in diameter and a kiloparsec in thickness. It contains about two hundred billion (2×1011) stars and has a total mass of about six hundred billion (6×1011) times the mass of the Sun.Other morphologiesHoag's Object, an example of a ring galaxy. Credit:Hubble Space Telescope/NASA/ESA.Peculiar galaxies are galactic formations that develop unusual properties due to tidal interactions with other galaxies. An example of this is the ring galaxy, which possesses a ring-like structure of stars and interstellar medium surrounding a bare core. A ring galaxy is thought to occur when a smaller galaxy passes through the core of a spiral galaxy. Such an event may have affected the Andromeda Galaxy, as it displays a multi-ring-like structure when viewed in infrared radiation.A lenticular galaxy is an intermediate form that has properties of both elliptical and spiral galaxies. These are categorized as Hubble type S0, and they possess ill-defined spiral arms with an elliptical halo of stars. (Barred lenticular galaxies receive Hubble classification SB0.)NGC 5866, an example of a lenticular galaxy. Credit:Hubble Space Telescope/NASA/ESAIn addition to the classifications mentioned above, there are a number of galaxies that can not be readily classified into an elliptical or spiral morphology. These are categorized as irregular galaxies. An Irr-I galaxy has some structure but does not align cleanly with the Hubble classification scheme. Irr-II galaxies do not possess any structure that resembles a Hubble classification, and may have been disrupted. Nearby examples of (dwarf) irregular galaxies include the Magellanic Clouds.Dwarf galaxyDespite the prominence of large elliptical and spiral galaxies, most galaxies in the universe appear to be dwarf galaxies. These tiny galaxies are about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.Many dwarf galaxies may orbit a single larger galaxy; the Milky Way has at least a dozen such satellites, with an estimated 300-500 yet to be discovered. Dwarf galaxies may also be classified as elliptical, spiral, or irregular. Since small dwarf ellipticals bear little resemblance to large ellipticals, they are often called dwarf spheroidal galaxies instead
What are the 2 components of the usar family readiness program?
2
What are the release dates for Spiral Zone - 1987 The Hacker 1-13?
Spiral Zone - 1987 The Hacker 1-13 was released on: USA: 7 October 1987
List all components needed to connect 2 computers together?
All the components needed to connect 2 computers together are two Ethernet cards, a network switch and 2 Ethernet cables. Alternatively a single USB transfer cable can be used for simple file transfers.
Why does your galaxy from your view not look like other sprial galaxies?
Good question; why can't you see your own face without using a mirror? Answers to BOTH questions; because we're INSIDE our faces - and inside our galaxy - and we can't see the whole thing. From the astronomy perspective, it's even worse; imagine being a cell in one of your tonsils, and trying to see your entire body. Our Sun is about 2/3 of the way out one of the spiral "arms", and we can't see the whole thing.
How old are barred galaxies?
Barred galaxies per se do not exist. They are just a sub category of spiral galaxies of which about 2/3rds are barred spiral galaxies.
What are the 3 common galaxies?
galaxie 1, 2, 3, 4 and 5
What is most common galaxies?
there are 3 types of galaxies. 1.spiral 2.elliptical 3.irregular the main galaxy in our universe would be a spiral galaxy
How are spiral galaxys alike barred spiral galaxys?
Barred galaxies per se do not exist. They are just a sub category of spiral galaxies of which about 2/3rds are barred spiral galaxies. A barred spiral galaxy has a central bar shaped structure composed of stars whereas a non barred spiral galaxy does not. See related link for a pictorial of the difference.
What do spiral and elliptical galaxies have in common?
They are in space. (: you're welcome.
Can 2 spiral galaxies create a elliptical galaxy?
yes they can and if that happens the galaxy will be destroyes :)
What 2 types of galaxies are barred and normal?
Milky Way
How is a spiral galaxy and a barred galaxy alike?
See related questions
What are the four galaxies?
The 4 types of galaxies are spiral, barred spiral,elliptical and irregular. 1. Spiral galaxy is easiest to identify due to its spiral structure and has its dust and gas scattered out evenly. Two good examples are the Milky Way Galaxy and Andromeda Galaxy. 2. Barred Spiral looks somewhat like a spiral galaxy, but in the first stages. Rather than having the same look as the spiral galaxy, the gas and dust in a barred galaxy are compressed near the center, with unevenness of the gas and dust, even though it still forms somewhat of a spiral. 3. Elliptical Galaxies are one of the largest galaxies with billions of solar systems clustered to appear as one star. With dust and gas scattered throughout, these galaxies appear to be a round shape and tend to hardly contain interstellar matter. 4. Irregular galaxy is also easy to identify because it is poorly structured and are even sometimes called dwarf irregular galaxies.
How does the Andromeda galaxy compare with the milky way galaxy?
They are both spiral galaxies, except the Milky Way is a barred spiral and the Andromeda is a typical spiral galaxy. The Andromeda has at least twice as many stars as the Milky Way, and it has more mass. The galaxies are going to merge in 4 billion years, and now they are about 2 million light years apart.
What are four general shapes of galaxies?
Galaxies have different shapes because of what happens throughout their lives. Any galaxy, at one point or another, will encounter another or many galaxies. When encounters occur, gravity takes over. The larger of the two galaxies will consume the smaller one, this is called galactic cannibalism. The act of absorbing another galaxy will change the size of the galaxy it's shape and even the speed of its rotation. Our own galaxy, The Milky Way, is as large it is (100000-150000 Light years across.) because of galactic cannibalism. The Milky Way is as we speak consuming two other small galaxy. And in about 2 billion years, our nearest nieghbor, the Andromeda Galaxy, will collide with our galaxy. Both the Milky Way and Adromeda galaxy are spiral galaxies, but after they collide the resulting new galaxy will an elliptical galaxy, which looks like a bright white sphere.
Why are irregular galaxies irregular?
An irregular galaxy is a galaxy that does not have a regular shape, like a spiral or an elliptical galaxy.[1] The shape of an irregular galaxy is uncommon - they do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.[2] Collectively they are thought to make up about a quarter of all galaxies. Most irregular galaxies were once spiral or elliptical galaxies but were deformed by gravitational action. Irregular galaxies also contain abundant amounts of gas and dust.
