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name the different shapes of the galaxies in the universe.

 Galaxies are classified into three main types: spiral galaxies, elliptical galaxies, and irregular galaxies.

Spiral galaxies, such as the Milky Way, consist of a flat disk with a bulging center and surrounding spiral arms. The galaxy's disk includes stars, planets, dust, and gas—all of which rotate around the galactic center in a regular manner.

This spinning motion, at speeds of hundreds of kilometers per second, may cause matter in the disk to take on a distinctive spiral shape like a cosmic pinwheel. Some spiral galaxies obtain even more interesting shapes that earn them descriptive names, such as sombrero galaxies.

Older stars reside in the bulge at the center of the galactic disk. Many new stars also form in spiral systems, and their disks are surrounded by a halo, which scientists believe is rich with mysterious dark matter.

Elliptical galaxies are shaped as their name suggests. They are generally round but stretch longer along one axis than along the other. They may be nearly circular or so elongated that they take on a cigarlike appearance.

Elliptical galaxies contain many older stars, up to one trillion, but little dust and other interstellar matter. Their stars orbit the galactic center, like those in the disks of spiral galaxies, but they do so in more random directions. Few new stars are known to form in elliptical galaxies.

The universe's largest known galaxies are giant elliptical galaxies, which may be as much as two million light-years long. Elliptical galaxies may also be small, in which case they are dubbed dwarf elliptical galaxies.

Galaxies that are not spiral or elliptical are called irregular galaxies. Irregular galaxies appear misshapen and lack a distinct form, often because they are within the gravitational influence of other galaxies close by.

Galactic Mergers

Some galaxies occur alone or in pairs, but they are more often parts of larger associations known as groups, clusters, and superclusters.

Galaxies in such groups often interact and even merge together in a dynamic cosmic dance of interacting gravity. Mergers cause gases to flow towards the galactic center, which can trigger phenomena like rapid star formation.

Our own Milky Way may someday merge with the Andromeda galaxy—just two million light-years away and visible to the naked eye from Earth's Northern Hemisphere.

These intergalactic processes may be part of natural evolution by which irregular galaxies transform into one of the other shapes, and by which spiral galaxies eventually become elliptical galaxies—as scientists believe they must.

Galaxy Origins

Most astronomers suggest that galaxies formed shortly after a cosmic "big bang" that began the universe some 10 billion to 20 billion years ago. In the milliseconds following this explosion, clouds of gases began to coalesce, collapse, and compress under gravity to form the building blocks of galaxies.

Scientists are divided on just how galaxies first formed. Some believe that smaller clusters of about one million stars, known as globular clusters, formed first and later gathered into galaxies. Others believe that galaxies formed first and that only later did the stars within them begin to gather into smaller clusters.

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 There are 4 different shapes of galaxies are :

(a) Spiral ; 

(b) Elliptical ;

(c) Lenticular ;

(d)  and Irregular. 

Galaxy Shapes

Image credit: NASA/JPL-Caltech/UCLA

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Galaxy shapes have 3 broad categories, based on the role of the bulge (the round distribution of stars at the center) and the disk (the flat distribution that includes the spiral arms).

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[Spiral] Spiral

Spiral galaxies usually consist of two major components: A flat, large disk which often contains a lot of interstellar matter (visible sometimes as reddish diffuse emission nebulae, or as dark dust clouds) and young (open) star clusters and associations, which have emerged from them (recognizable from the blueish light of their hottest, short-living, most massive stars), often arranged in conspicuous and striking spiral patterns and/or bar structures, and an ellipsoidally formed bulge component, consisting of an old stellar population without interstellar matter, and often associated with globular clusters. The young stars in the disk are classified as stellar population I, the old bulge stars as population II. The luminosity and mass relation of these components seem to vary in a wide range, giving rise to a classification scheme. The pattern structures in the disk are most probably transient phenomena only, caused by gravitational interaction with neighboring galaxies.

Our sun is one of several 100 billion stars in a spiral galaxy, the Milky Way.

[S0] Lenticular (S0)

These are, in short, "spiral galaxies without spiral structure", i.e. smooth disk galaxies, where stellar formation has stopped long ago, because the interstellar matter was used up. Therefore, they consist of old population II stars only, or at least chiefly. From their appearance and stellar contents, they can often hardly be distinguished from ellipticals observationally.

[Elliptical] Elliptical

Elliptical galaxies are actually of ellipsoidal shape, and it is now quite safe from observation that they are usually triaxial (cosmic footballs, as Paul Murdin, David Allen, and David Malin put it). They have little or no global angular momentum, i.e. do not rotate as a whole (of course, the stars still orbit the centers of these galaxies, but the orbits are statistically oriented so that only little net orbital angular momentum sums up). Normally, elliptical galaxies contain very little or no interstellar matter, and consist of old population II stars only: They appear like luminous bulges of spirals, without a disk component.

However, for some ellipticals, small disk components have been discovered, so that they may be representatives of one end of a common scheme of galaxy forms which includes the disk galaxies.

[Irregular] Irregular

Often due to distortion by the gravitation of their intergalactic neighbors, these galaxies do not fit well into the scheme of disks and ellipsoids, but exhibit peculiar shapes. A subclass of distorted disks is however frequently occuring.

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Science revealed to us that universe as we know it, is composed of billions of galaxies like our own Milky Way. When you consider how many stars are just in our own galaxy you can get just a small idea how big our universe really is. Despite this astronomers have made great strides in learning more about the galaxies and their different characteristics. One aspect that was defined early was their shapes. Thanks to the work of famous astronomer Edwin Hubble we know that just about any galaxy in the universe will have one of 4 different shapes, spiral, elliptical, lenticular, and irregular.

Spiral galaxies are one of the most familiar galaxy shapes. In fact when most people think of a galaxy, this type of galaxy shape is the first to come to mind. This is because the Milky Way is a prime example of a spiral galaxy. A spiral galaxy looks like a pinwheel. It is basically the nucleus with its different arms spiraling outwards. Spiral galaxies can be tight or loose to varying degrees. One important fact about spiral galaxies is that young stars are formed in the outer arms while older stars are found near the center.The next two types of galaxies are elliptical and lenticular shaped galaxies. These types are the kinds that are the most similar. First they have few or no dust lanes and are largely composed of older mature stars. These types seldom have star forming areas. Of the four galaxy shapes this is the most cohesive and organized.

The final galaxy shape is the irregular galaxy shape. Irregulars have an indeterminate shape. These galaxies are often small and dont have enough gravitational force to organize into a more regular form. The Hubble telescope has taken images of famous irregular galaxies like the Magellanic Clouds. Irregular galaxies can also be large galaxies that have undergone a major gravitational disturbance.

As you now see the four basic galaxy shapes seem to cover just about every type of galaxy out there. Like any classification of shape there are also subcategories. An interesting observation recently made about the shape of galaxies is the role that their formation plays in determining their shape. It is now thought that galaxies get their shape as they naturally develop, merge with other galaxies or disrupt each others path. This is another great mystery as we dont currently have the technology to plot out the complete paths of galaxies in the universe.

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Elliptical Galaxy LikeESO 325-G004
Spiral Galaxy Like Andromeda Galaxy
Lenticular Galaxy LikeNGC 5856
Irregular Galaxy Like NGC 1427A
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  1. elliptical
  2. spiral
  3. ring
  4. lenticular
  5. ​irregular
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1.the whirpool galaxy. 2.the andromeda galaxy.
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