Some galaxies look like round balls.
They are made of old stars. These stars are red. They do not make many new stars. They are very big and bright. Can you find them in the sky?
Some galaxies look like round balls or eggs.
They are made of very old stars. These stars give the galaxies a red color.
These galaxies do not have much gas or dust. Because they lack this, they do not make many new stars. Most of the stars move in random paths. They do not follow a flat shape like other galaxies.
Every big elliptical galaxy has a black hole at its center. These black holes are very massive. They help hold the galaxy together.
Some of these galaxies are giants. They can have over one hundred trillion stars! They are often found in large groups of galaxies. These big galaxies are very important to their groups.
An elliptical galaxy is a type of galaxy. It has a shape like an egg or a ball.
These galaxies are very different from spiral galaxies. They do not have a flat disk. Instead, their stars move in random paths around the center.
Most stars in these galaxies are very old. This gives them a red color. They do not have much gas or dust. Because they lack this material, they do not make many new stars. However, they might make new stars during a merger. A merger is when two galaxies crash into each other.
Elliptical galaxies come in many sizes. Some are tiny dwarf galaxies. Others are supergiants with over one hundred trillion stars!
Every massive elliptical galaxy has a supermassive black hole at its center. The mass of the black hole is linked to the mass of the galaxy.
These galaxies are often found in the middle of large galaxy clusters.
An elliptical galaxy is a special type of galaxy. It has a shape like an egg or a ball.
These galaxies are one of three main types. Edwin Hubble described them in his 1936 work, "The Realm of the Nebulae." He also described spiral and lenticular galaxies. Most elliptical galaxies are made of old, low-mass stars. They often have many globular clusters around them. These clusters can be red and metal-rich or blue and metal-poor.
How these galaxies work is quite different from spiral galaxies. They do not have flat disks or much gas and dust. This means they have very little star formation activity. They are mostly made of older stars, which gives them a red color. However, they can make new stars during a brief period. This happens when they merge with other galaxies.
Some galaxies even have dust lanes from these crashes. Scientists think central black holes might stop gas from cooling to make stars.
Edwin Hubble studied these shapes a long time ago. He once thought that elliptical galaxies turned into spiral galaxies. We now know that this idea was false. Instead, a galaxy might build a disk around its shape by collecting gas.
Scientists still study how they form today. They look at whether galaxies merge with gas or without gas. This helps them understand if a galaxy will rotate fast or slow.
These galaxies come in a huge range of sizes. Some are dwarf ellipticals with tens of millions of stars. Others are supergiants with over one hundred trillion stars.
The galaxy IC 1101 is a supergiant elliptical. It is the central galaxy of Abell 2029. Another huge one is ESO 383-76. Every massive elliptical galaxy has a supermassive black hole at its center. The mass of the black hole is tied to the mass of the galaxy.
You can find these galaxies in interesting places. They are often found close to the centers of galaxy clusters. They make up about 10% to 15% of the Virgo Supercluster.
Some, like M87, have black holes that were the first to be imaged. Others, like Centaurus A, have unusual dust lanes. Even though they look smooth, they are actually very complex 3D shapes. They are a vital part of our amazing universe.
An elliptical galaxy is a massive collection of stars shaped like an egg or a sphere. Unlike the flat disks of spiral galaxies, these objects are three-dimensional structures. They often appear smooth and featureless in images. They are one of the three main classes of galaxies. Edwin Hubble first described them in his 1936 work, "The Realm of the Nebulae." He categorized them alongside spiral and lenticular galaxies.
The internal makeup of these galaxies follows a specific pattern. Most elliptical galaxies consist of older, low-mass stars. They contain very little interstellar medium, which is the gas and dust between stars. Because they lack these raw materials, star formation is typically minimal. This lack of new, hot stars gives many elliptical galaxies a reddish color. They are often surrounded by large numbers of globular clusters. These clusters usually fall into two groups: red, metal-rich clusters and blue, metal-poor clusters.
Scientists study how these galaxies form through different types of mergers. One theory involves the merging of disk galaxies. Recent research suggests two specific paths. A "wet" merger involves galaxies rich in gas. These mergers may produce lower-mass, fast-rotating elliptical galaxies. A "dry" merger involves galaxies that are poor in gas. These may help build the higher-mass, slow-rotating systems.
Some galaxies may even show dust lanes, which can be evidence of a past merger event.
Elliptical galaxies vary more in size than any other galaxy type. They range from dwarf ellipticals to massive supergiants. Dwarf ellipticals may contain only tens of millions of stars. They can be as small as a typical globular cluster. On the other end, supergiant elliptical galaxies can hold over one hundred trillion stars.
One famous example is IC 1101, a supergiant in the Abell 2029 cluster. Another massive galaxy is ESO 383-76. These giants often dominate the centers of galaxy clusters.
Hubble developed a system to classify these shapes using an integer. This number describes how elongated the galaxy looks. It is based on the ratio of the major axis to the minor axis. An E0 galaxy is nearly spherical. As the number increases toward E7, the shape becomes more elongated. However, some E4 to E7 galaxies are actually lenticular galaxies seen at an angle.
Astronomers also distinguish between "boxy" giant ellipticals and "disky" dwarf ellipticals. The boxy shapes result from random stellar motions.
Every massive elliptical galaxy contains a supermassive black hole at its center. There is a tight correlation between the mass of the black hole and the mass of the galaxy. This is known as the M–sigma relation. This relation links the velocity dispersion of surrounding stars to the black hole's mass.
In the Virgo Supercluster, elliptical galaxies make up about 10% to 15% of the total population. They are most commonly found near the centers of dense galaxy clusters.
Many notable examples help us understand these systems. M87 is a famous elliptical galaxy. Its central supermassive black hole was the first ever imaged by the Event Horizon Telescope. Centaurus A is another unique example. It is an elliptical/lenticular radio galaxy with unusual dust lanes. The galaxy IC 1101 is one of the largest known. Even the smallest dwarf ellipticals are important because they contain significant amounts of dark matter. These diverse objects show how complex the large-scale structure of our universe truly is.
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