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Here are the 50 most spectacular galaxy pictures of all time: From pictures of the Andromeda Galaxy to the pictures of the "Cosmic Tinker Bell Triplet," from pictures of colliding galaxies to the pictures of the Hubble Deep Fields. These images are truly amazing! They are the best pictures of galaxies captured by some of the most powerful telescopes of NASA/ESA/ESO, etc. This page displays all the 50 pictures along with their descriptions. However, if your page is too slow to load, you might want to view only 10 pictures at a time by starting from this page.
Apart from the visible light spectrum, instruments on NASA's and ESA's powerful telescopes can detect infrared rays, ultraviolet rays, X-rays, gamma rays, and other radiation emitted by stars, galaxies, nebulae, etc. The invisible spectrum of electromagnetic radiation can reveal features not seen in the visible light spectrum.
Since our eyes can only see the visible light spectrum, we have to use different colors to represent infrared, ultraviolet, X-ray and other radiation. This is how the so-called 'false-color' or 'color-coded' galaxy pictures are made. In the following images, you'll see both true-color and false-color (or color-coded) galaxy pictures.
The above picture shows a true-color view of the Andromeda Galaxy, as seen through a 24-inch (60 cm) Burrell Schmidt telescope of the Warner and Swasey Observatory. The two small, spherical objects near the galaxy are M32 (NGC 221) and M110 (NGC 205). They are small satellite galaxies of the Andromeda Galaxy.
On a dark, moonless, and cloudless night, the Andromeda Galaxy is sometimes visible to the naked eye as a faint, hazy patch in the direction of the Andromeda constellation. In the Northern Hemisphere, the best time to spot this galaxy is around the midnights of the autumn/fall season, especially during the months of October and November. It is a huge galaxy, containing an estimated 1,000,000,000,000 stars! However, without binoculars or a telescope it may merely look like a blurred, dim star with a misty patch surrounding it. On a very dark night, the faint haze can appear as long as the full moon, and about half as wide.
Located at an estimated distance of about 2.2 to 2.5 million light-years from the Earth, the Andromeda Galaxy is popularly considered to be the nearest large spiral galaxy to our own Milky Way Galaxy. But is it really the nearest galaxy to the Milky Way Galaxy? The answer is both yes and no, depending upon whether you want to ignore the fine print or not. The fine print is that the Milky Way Galaxy has a number of small satellite galaxies, which are actually much closer to it than the Andromeda Galaxy. A few examples of these satellite galaxies are the Canis Major Dwarf Galaxy, the Sagittarius Dwarf Elliptical Galaxy (SagDEG), the Large Magellanic Cloud, and the Small Magellanic Cloud.
What makes the Andromeda Galaxy unique is that it is the nearest 'non-satellite' and large spiral galaxy that can be considered an equal of the Milky Way Galaxy. It contains an estimated one trillion stars, and has an estimated length of about 200,000 to 260,000 light-years. In comparison, our Milky Way Galaxy is a barred spiral galaxy, which contains an estimated 200 to 400 billion stars, and has an estimated length of about 100,000 to 120,000 light-years. However, in spite of being smaller than the Andromeda Galaxy, the Milky Way Galaxy is thought to be slightly more massive, because it is thought to contain more dark matter than the former.
Another interesting fact about the Andromeda Galaxy is that it is moving toward us with a speed exceeding 112 kilometers (69 miles) per second. At such a breathtaking speed, we could travel from the Earth to the Moon in just one hour! However, the Andromeda Galaxy is so far from us that with its current speed it will take about 4 billion years to collide with the Milky Way Galaxy. Astronomers predict that when the two galaxies collide, they will eventually merge to form a single, huge elliptical galaxy. To know more about the fate of the two galaxies, you might want to watch this video. The process of galactic collisions and mergers can take billions of years. Astrophysicists can gain a better understanding of the process by observing other colliding galaxies, which could be in different stages of their galactic mergers.
The above picture shows an ultraviolet view of the Andromeda Galaxy, based on observations made by the Galaxy Evolution Explorer (GALEX) telescope of NASA. It has been color-coded to represent ultraviolet light. Far-ultraviolet light is represented by blue color and near-ultraviolet light is represented by orange color. The blue-white bands visible in this picture represent those regions of the galaxy that harbor hot young massive stars. The darker, blue-gray lanes represent regions of cool interstellar dust. The orange-white bulge in the center of the galaxy represents a dense collection of relatively cooler and older stars that formed a long, long time ago.
The Sombrero Galaxy (Messier 104) is an unbarred spiral galaxy, but it is tilted almost edge-on toward the Earth, which makes it look like a sombrero (a type of a broad-brimmed Mexican hat). It has a diameter of about 50,000 light-years and its distance from the Earth is about 28 million light-years. It can be easily spotted in the direction of the Virgo constellation with the help of a small telescope. The above Hubble Space Telescope picture of the galaxy shows what it looks like when seen from our vantage point. It looks as if a disk or a ring of dust lanes is surrounding a bulbous central core.
The beautiful picture displayed above is a composite image of the Sombrero Galaxy, formed by combining its visible light spectrum and (color-coded) infrared light spectrum images, taken by the Hubble Space Telescope and the Spitzer Space Telescope, respectively. This picture reveals young star-forming regions in the clumpy areas present near the far edges of the galaxy. A supermassive black hole (as massive as one billion suns) is thought to be present in the center of the galaxy. Also see the previous picture for more information about this galaxy.
The Whirlpool Galaxy (M51 or NGC 5194) is a grand-design spiral galaxy located at a distance of about 31 million light-years from the Earth, in the direction of the Canes Venatici (the Hunting Dogs) constellation. It presents a face-on view, with its two prominent winding arms giving it a look of a swirling whirlpool. Its spiral arms are long lanes of gas and interstellar dust studded with stars and star-forming regions. This galaxy allows astronomers to study star-forming processes and the structure of a classical spiral galaxy.
The above picture of the galaxy was taken by the Hubble Space Telescope's Advanced Camera for Surveys. It shows pink, star-forming regions in the arms of the galaxy. These arms are factories of star-formation, and home to young and new-born stars. The yellowish central core contains older stars. The yellowish spherical object on the right side of the picture is a companion, interacting galaxy called NGC 5195. Its gravity creates waves or ripples, which compress the dust and gases in the arms of the Whirlpool Galaxy. This compression leads to the birth of new stars. Some of the largest stars explode as bright supernovae, while others emerge as bright blue star clusters from the mayhem, after intense stellar winds have swept away the obscuring dust.
Located about 21 million light-years away from the Earth toward the Ursa Major (Great Bear) constellation, the Pinwheel Galaxy (M101 or NGC 5457) is another face-on, 'grand design' spiral galaxy. It is a huge galaxy containing about a trillion stars. Its diameter is about 170,000 light-years, which is nearly 70% larger than that of our Milky Way Galaxy.
The above galaxy picture shows its spiral arms studded with clusters of newborn stars. These stars are formed when high density clouds of molecular hydrogen contract and collapse under their own gravitational force. Such waves of contractions are often triggered by the gravity of an interacting galaxy. Young and old stars are evenly distributed along the spiral arms of this galaxy.
The mayhem of a galactic collision is depicted by the above picture of the Cartwheel Galaxy (ESO 350-40). It is a lenticular galaxy (or an intermediate between an elliptical galaxy and a spiral galaxy) located about 500 million light-years away from the Earth in the direction of the Sculptor constellation. According to astronomers, a smaller galaxy (possibly one of the two objects on the left side of the picture) plunged right through its center. This happened about 100 million years ago. The complicated shape of the galaxy is thought to be the result of that collision. The collision created ripples in the Cartwheel Galaxy, just like a stone thrown in a pond creates ripples in it. An animation of a similar collision that has occurred in a different galaxy is shown in this video.
We can rather say that the collision created a cosmic tsunami, which expanded at 89.3 kilometers (55.5 miles) per second, and set off a firestorm of new star creation. The bright-blue outer ring visible in the above picture represents the first wave of the tsunami. This ring emits intense ultraviolet radiation, as countless stars having 5 to 20 solar-masses are forming in this region. They are clustered around super-massive star clusters. The X-rays indicate massive X-ray binary systems. The inner ring and nucleus of the galaxy are yellow-orange. These regions have much lesser star formation activity. The red specks are regions thought to contain high concentrations of organic molecules. Older, less-massive stars look greenish in color.
The above picture is a false-color composite image of the galaxy. The color-codes are as follows: Red represents infrared light detected by the Spitzer Space Telescope, green represents B-band visible light detected by the Hubble Space Telescope, blue represents far-ultraviolet radiation detected by the Galaxy Evolution Explorer (GALEX), and purple represents X-rays detected by the Chandra X-ray Observatory.
The Centaurus-A Galaxy (NGC 5128 or Caldwell 77) is an active galaxy located about 12 million light-years away from the Earth in the Centaurus (Centaur) constellation of the Southern Hemisphere. An elliptical galaxy might have merged with a spiral galaxy to form this peculiar galaxy. A supermassive black hole having 100 million solar masses lies in its heart. Huge energy is released as matter falls in the black hole. Strong radio waves can be detected from the Earth. The above composite picture of the galaxy shows spectacular lobes and relativistic jets of high-energy particles shooting out from its center. Some of these powerful jets have half the speed of light, and they are thousands of light-years in length.
In the above picture, blue color represents X-ray data from the Chandra X-ray Observatory, and the orange color represents 870-micron submillimetre data from ESO's Atacama Pathfinder Experiment telescope. The visible-light data shows stars and dust-lanes of the galaxy. Clusters of young, blue stars are present along the edges of the dust lanes. The glow that fills the center of the picture comes from hundreds of billions of cooler and older stars. The X-ray emitting blue jets of plasma extend thousands of light-years from the center of the galaxy.
The Antennae Galaxies (NGC 4038/4039 or Caldwell 60/61) are two colliding galaxies located about 45 million light-years away from the Earth in the direction of the Corvus (Crow) constellation. When seen from ground-based telescopes, the galaxy pair looks like the head and antennae of an insect, because of two tidal tails that extend far from the cores. These galaxies are starburst galaxies i.e. they have an exceptionally high rate of new star formation triggered by the collision. Billions of new stars will be formed in these galaxies, as they go through their collision course.
The above Hubble Space Telescope picture of the galaxies shows bright, dense regions of star birth, called super star clusters. Each cluster contains tens of thousands of young stars. The cores of the original galaxies are visible as orange-yellow blobs on the lower left and upper right of the picture. These cores consist of the original, old stars of the two galaxies. The brown filaments consist of interstellar dust. Newly formed stars and star-forming regions appear bright, bluish-white. The pink areas are regions containing glowing hydrogen. Since this picture zooms at the cores of the galaxies, the tidal tails are not shown. It sort of looks like the lateral view of a human skull!
The above picture of interacting galaxies looks like an awesome cosmic-rose studded with shiny jewels! It shows Arp 273, a pair of interacting galaxies located about 300 million light-years away from the Earth in the direction of the Andromeda constellation. The larger spiral galaxy, UGC 1810, is tidally distorted into a rose-like shape by the gravity of the smaller galaxy, UGC 1813. The smaller galaxy looks like the stalk of the rose. The countless blueish dots in this picture are hot, young stars. The two galaxies are separated from each other by tens of thousands of light-years.
The Cigar Galaxy (M82) is a starburst galaxy in the Ursa Major (Great Bear) constellation. Its distance from the Earth is about 12 million light-years. The rate of new star formation in the central regions of the galaxy is 10 times faster than what it is in our Milky Way Galaxy. The above optical and infrared composite picture of the galaxy shows flame-like plumes of hydrogen gas blasting outward from its central regions. What look like scattered pale stars are actually clusters of hundreds of thousands of stars.
Here is another composite picture of the Cigar Galaxy (see a description of the galaxy below the previous picture) made by combining images from three different telescopes. The Chandra X-ray Observatory's X-ray data is represented by blue color, the Spitzer Space Telescope's infrared data is represented by red color, and the rest is mostly visible light from the Hubble Space Telescope. The blue color represents gas that has been heated to millions of degrees by the violent outflow from the central star-forming regions of the galaxy. The red color represents cooler gases and dust. The orange color represents hydrogen gas at 10,000 degrees Celsius.
The above picture looks a bit like a person wearing a long, white cloak studded with jewels. It is a Hubble Space Telescope image of M100 (NGC 4321), a grand design spiral galaxy located about 50 million light-years away from the Earth in the direction of the Coma Berenices constellation. It has a diameter of 160,000 light-years.
The above picture shows the grand-design spiral galaxy M74 (NGC 628), as seen through the Hubble Space Telescope. It is located in the direction of the Pisces (Fish) constellation, at a distance of 32 million light-years from the Earth. The bright knots of glowing gas along the spiral arms indicate regions of star formation.
NGC 6872 and IC 4970 are interacting galaxies located more than 212 million light-years away from the Earth in the direction of the Pavo (Peacock) constellation of the Southern Hemisphere. NGC 6872 is one of the largest known spiral galaxies. Its length from tip-to-tip is more than 522,000 light-years, which is at least four times the length of our Milky Way Galaxy! The diameter of its central 'bar' is 26,000 light-years. In the above picture, NGC 6872 is visible as the long galaxy that sort of looks like the 'integral symbol' of calculus. Its companion, IC 4970, is the smaller disk-shaped galaxy seen just above the center of the picture. The bright star visible near the lower right of the center is not a part of either of these two galaxies. It is a nearby star located in the Milky Way Galaxy. The blueish dots present in the upper left spiral arm of NGC 6872 indicate star-forming regions. The central bar of the galaxy contains the oldest stars and no star-forming regions.
Displayed above is a sharp picture of the Bode's Galaxy (M81) taken by the Hubble Space Telescope. It is a spiral galaxy located about 12 million light-years away from the Earth in the direction of the Ursa Major (Great Bear) constellation. Its spiral arms are studded with bluish stars, which are young hot stars formed only a few million years ago. The greenish spots on the arms are dense regions of star formation. The brown, winding streaks are dust lanes. The central bulge of the galaxy contains the oldest stars. It has an active galactic nucleus, which contains a supermassive black hole with 70-million solar masses.
The above picture shows finely textured dust-lanes around the brightly glowing core of NGC 3190, a spiral galaxy located about 77 million light-years away from the Earth in the direction of the Leo constellation. It is the largest galaxy in the 'Hickson 44' group of galaxies. Its dust lanes and central disk look warped, possibly due to the effects of gravity of other galaxies in the Hickson 44 group. Dust lanes are bands of interstellar dust, which appear like dark streaks against the brighter background of a galaxy.
NGC 1300 is a barred spiral-galaxy located about 69 million light-years away from the Earth in the direction of the Eridanus (River) constellation. In an unbarred spiral-galaxy, the arms wind all the way down to its center, but in a barred spiral-galaxy they are connected to the two ends of a straight bar of stars that contains the nucleus of the galaxy at its center. In the above galaxy picture, you can see fine structures traced by winding, brownish dust-lanes. If you look closely at its center, you'll see a spiral within a spiral. The length of the small spiral in the center is about 3,300 light-years. The entire galaxy has a length of about 110,000 light-years.
The above picture shows NGC 1232, an intermediate spiral-galaxy lying in the Eridanus (River) constellation. Its distance from the Earth is about 65 million light-years. It contains billions of young and old stars. Clusters of young stars appear as the bluish regions along its spiral arms. Old stars are present in the yellowish core of the galaxy. The dust lanes appear brown. A small companion galaxy near the top left looks like the Greek letter "theta."
Hoag's Object is a mysterious, ring-shaped galaxy located about 600 million light-years away from the Earth in the direction of the Serpens Caput (Serpent's Head) constellation. Its diameter is about 100,000 light-years. It consists of an outer ring and an inner ball of densely packed stars. The two are separated by a gap, as can be seen in the above Hubble Space Telescope picture of the galaxy. The outer bluish ring is thought to consist of younger stars, whereas the inner yellowish ball is thought to consist of older stars. What created this unusual shape of the galaxy still remains a mystery. A very interesting coincidence is the presence of yet another ring galaxy located far, far behind the Hoag's Object; it is visible through the gap between its outer ring and its inner ball, roughly near the "one o'clock" position!
NGC 6384 is a spiral galaxy located in the direction of the Ophiuchus (Serpent Bearer) constellation. Its distance from the Earth is about 80 million light-years. Its diameter is about 150,000 light-years. The above picture is a close-up shot of its central region. It shows a yellowish core surrounded by bluish spiral arms and brownish dust-lanes.
AM 0644-741 is a ring galaxy located in the direction of the Volans constellation in the Southern Hemisphere. Its distance from the Earth is about 300 million light-years. As shown in the above picture, its egg-shaped structure consists of two parts -- an outer ring of young, bluish star-clusters, and an inner, yellowish nucleus. The sparkling outer ring looks like a bracelet studded with diamonds. Its diameter is about 150,000 light-years, which is larger than that of our Milky Way Galaxy. Another galaxy is thought to have shot right through its center, creating its ring-like shape, and triggering a massive production of new stars in the ring due to the gravitational shock. Before that, it might have been a normal spiral galaxy.
NGC 3314A and NGC 3314B are overlapping galaxies located in the direction of the Hydra constellation. They almost form a heart-shaped pattern in the center of the image. They are not gravitationally interacting or colliding, because they are separated by a distance of millions of light-years from each other. When seen from the Earth, they appear to be overlapping just because they happen to be in the same direction by chance. The dust-lanes of the foreground galaxy (NGC 3314A) are silhouetted against the brightness of the background galaxy (NGC 3314B).
Abell S0740 is a cluster of galaxies located in the direction of the Centaurus constellation. It consists of a diverse set of galaxies. The brightest galaxy in the cluster is a giant elliptical galaxy called ESO 325-G004. Its diameter is about 100,000 light-years and it contains an estimated 100 billion stars. Its enormous mass creates gravitational lensing. Its distance from the Earth is about 450 million light-years. Thousands of globular clusters orbit it. Each globular cluster is a compact group of hundreds of thousands of stars that are gravitationally bound together. Since the galaxy is located so far away from us, the globular clusters merely appear as tiny points of light around its halo in the above picture. A large spiral galaxy appears in the bottom left corner of the picture. Many other spiral and elliptical galaxies are present in the galaxy cluster.
NGC 2841 is a flocculent spiral-galaxy located in the direction of the Ursa Major (Great Bear) constellation. Its distance from the Earth is about 65 million light-years. The above picture is a close-up shot of its nucleus. Bluish star clusters and dust lanes are clearly visible around the yellowish nucleus. A flocculent spiral galaxy has short spiral arms instead of the prominent and well-defined galactic limbs of a 'grand design' spiral galaxy.
NGC 1672 is an barred spiral-galaxy located in the direction of the Draco constellation in the Southern Hemisphere. Its distance from the Earth is about 60 million light-years. The above picture shows star formation regions along its spiral arms. What appear as bluish dots along the arms are clusters of hot, young stars. The reddish spots are clouds of hydrogen gas, and the brownish streaks are dust-lanes.
SN 1994D was a 'type Ia supernova' explosion discovered in 1994 on the outskirts of the NGC 4526 galaxy. It looks like a shining flashlight in the lower left portion of the above picture. The NGC 4526 galaxy is a spiral galaxy located in the direction of the Virgo constellation. Its distance from the Earth is about 50 million light-years. A type Ia supernova occurs in a binary system i.e. a system of two stars orbiting each other. One of the stars in the system must be a white dwarf. A white dwarf is so dense that a teaspoon of its matter would weigh five tons on Earth! The intense gravity of the white dwarf keeps pulling material from its companion star. This keeps increasing the mass of the white dwarf. The companion star can be a smaller white dwarf or even a giant star. When the mass of the white dwarf star reaches 1.4 solar masses, a nuclear chain reaction occurs that makes it to explode. The light from the explosion is so bright that it can briefly outshine all the stars in its galaxy!
The strange NGC 7742 galaxy shown above looks like a fried egg ('sunny side up'). It is a spiral galaxy located about 72 million light-years away from the Earth in the direction of the Pegasus constellation. It is a Type 2 Seyfert galaxy. A Seyfert galaxy is a galaxy whose nucleus shows emissions lines in its spectrum, due to highly ionized gas. The spectrum of a Type 1 Seyfert galaxy shows both narrow and broad emission lines, and the spectrum of a Type 2 Seyfert galaxy shows only narrow emission lines. The yellowish core of the NGC 7742 looks like a yolk in the above picture. It may contain a massive black hole. The whitish inner-ring surrounding the core gives it a unique look. This ring is a region of active star-birth. Its distance from the core is about 3,000 light-years. The diameter of the entire galaxy is about 36,000 light-years.
Over the course of several billion years, a small satellite-galaxy can get stretched into a ribbon-like structure, as it revolves around a large, massive galaxy. This ribbon-like structure of stars, dust and gas is called a tidal stream. Ultimately, the tidal stream may completely disappear by merging with the larger galaxy. The above picture shows a faint tidal stream around the Splinter Galaxy. The Splinter Galaxy is also known as the Knife Edge Galaxy or NGC 5907. It is a spiral galaxy located about 53 million light-years away from the Earth in the direction of the Draco constellation. The following illustration is an exaggerated look of a tidal stream: -
The above image is an artist's illustration of a tidal stream. The orange blob is a small satellite-galaxy revolving around a large, massive galaxy. Over the course of several billion years, it has got stretched into a 'tidal stream,' which looks like a bright ribbon of stars, dust and gas surrounding the large galaxy. For a real-life example of a tidal stream, see the previous picture of the Splinter Galaxy (NGC 5907).
Most of the giant galaxies that we see today were built from many smaller galaxies that merged together. This is an ongoing process. Galaxies often interact gravitationally with each other. The gravity of one galaxy distorts the shape of another galaxy. In some cases, the gravity of the larger galaxy slowly pulls out stars and other matter from the smaller galaxy, and assimilates it within itself. This process is called tidal stripping. In other cases, the galaxies collide with each other. If the colliding galaxies do not have sufficient momentum to continue traveling after the collision, their mutual gravity pulls them back toward each other. They collide a number of times and eventually merge together.
A number of small satellite-galaxies revolve around the Milky Way Galaxy. Since the Milky Way Galaxy is the larger galaxy, its stronger gravity slowly pulls out stars and other matter from these satellite galaxies. The Milky Way Galaxy will slowly assimilate these satellite galaxies within itself. This process is called galactic cannibalism. Astronomers also predict that the Andromeda Galaxy will collide and merge with the Milky Way Galaxy in the distant future. When galaxies collide and merge, the individual stars of the galaxies do not smash with each other, because the distances between individual stars are too vast.
Just about one in a million galaxies can be caught in the act of colliding. However, in the early Universe, colliding galaxies and mergers might have been more common, since the Universe was smaller and the galaxies were closer together. The following pictures show how interacting galaxies distort the shapes of each other to form tail-like structures and other interesting patterns. The process of galactic interactions, collisions, and mergers can take hundreds of millions or even several billion years to complete.
NGC 3169 and NGC 3166 are interacting galaxies located about 70 million light-years away from the Earth in the direction of the Sextans constellation. Even thought these galaxies are separated by a distance of thousands of light-years, their shapes are getting distorted due to each others gravity. As shown in the above picture, the shape of the left galaxy (NGC 3169) is warped, and the dust lanes of the right galaxy (NGC 3166) are fragmented.
The above picture shows a pair of interacting galaxies located in the direction of the Bootes (Herdsman) constellation. Their distance from the Earth is about 200 million light-years. The arms and the spiral structure of the larger galaxy (NGC 5754) are getting slightly distorted by the gravity of the smaller galaxy (NGC 5752). The smaller galaxy is going through a starburst episode. Its core is surrounded by massive and luminous star clusters.
Like a pair of cosmic dancers holding hands, the interacting galaxies, NGC 5257 and NGC 5258 are connected to each other by a dim bridge of stars. They are located about 300 million light-years away from the Earth in the direction of the Virgo constellation. New stars are forming in their disks. Supermassive black holes are also thought to be present in their centers. This pair of interacting spiral galaxies is also called Arp 240.
The Mice Galaxies (NGC 4676) are a pair of interacting galaxies located about 300 million light-years away from the Earth in the direction of the Coma Berenices constellation. They are getting ripped apart due to each others gravity. They are likely to collide again and again till they merge with each other after several passes. The long tail-like structures are formed because the gravitational pull is stronger near those ends of the galaxies that are closer to each other than those that are far apart.
The above picture shows colliding galaxies NGC 2207 and IC 2163. They are located about 114 million light-years away from the Earth in the direction of the Canis Major (Great Dog) constellation. The larger galaxy on the left (NGC 2207) is distorting the shape of the smaller galaxy on the right (IC 2163), and flinging out stars and gas from it into long streamers that stretch for nearly 100,000 light-years. Trapped in a mutual orbit around each other, both the galaxies will distort and disrupt each other. They are participating in a cosmic dance, which will last for billions of years and end in the merger of the two galaxies. The above picture was released by ESO. For a Hubble Space Telescope image of the same colliding galaxies, see this picture.
The above picture shows Arp 272, a pair of colliding galaxies (NGC 6050 and IC 1179). Located about 450 million light-years away from the Earth in the direction of the Hercules constellation, these colliding spiral galaxies are in close contact with each other through their swirling arms. A third, smaller galaxy is also visible near the bottom of the image. It could also be interacting with them.
Arp 194 is a peculiar group of interacting galaxies located about 600 million light-years away from the Earth in the direction of the Cepheus constellation. In the top portion of the above picture, two colliding galaxies are in the process of merging together. It looks like one of the galaxies has sprung a leak -- a spiral arm full of newborn stars is extending downward. The bluish arm looks like a cosmic fountain of stars, gas and dust. It looks like it is connected to the galaxy at the bottom, but it isn't; the galaxy visible at the bottom of the picture is a background galaxy located very far away from the interacting galaxies.
The above picture shows the aftermath of a head-on galactic collision. The elliptical galaxy on the left has shot right through the center of the galaxy on the right, creating its ring-like shape. The collision has triggered intense star-formation activity in the bluish ring, which is all that remains of what might once have been a spiral galaxy. This pair of colliding galaxies is called Arp 147. It looks like the number 10. It is located more than 400 million light-years away from the Earth in the direction of the Cetus constellation.
The above picture of Stephan's Quintet (Hickson Compact Group 92) shows not just two, but four interacting galaxies. They are locked in a cosmic dance of repeated close encounters. This compact group is named after Édouard Jean-Marie Stephan, a French astronomer who discovered it in 1877. It lies in the Pegasus constellation. As the name implies, we can see five galaxies in the group. However, the galaxy in the lower left of the picture is a foreground galaxy, located only about 40 million light-years away from the Earth. It is not a part of the group of the remaining four interacting galaxies that are located about 290 million light-years away from the Earth. The two colliding galaxies in the center of the picture appear very close to each other. Their interactions have triggered a frenzy of new star births. The shape of the barred spiral galaxy in the top right corner of the picture looks distorted. In fact, the shapes of all the three galaxies are distorted due to gravitational forces. Their spiral arms look very elongated. Long, tidal tails can also be seen. They are studded with a large numbers of star clusters. The elliptical galaxy in the lower right corner is less affected by the interactions. This video shows a simulation of multiple-galaxy collision.
The above Hubble Space Telescope picture show 12 different pairs of interacting or colliding galaxies. The process of galactic interactions, collisions, and mergers takes hundreds of millions of years (or even several billion years) to complete. The above galaxies are in different stages of their interactions/collisions, and this can help us understand the process better. Notice how their shapes are distorted by their gravities, and how they form peculiar shapes.
When we look at the sky, we mostly see stars of our own Milky Way Galaxy. These stars can obscure the views of faint, extremely distant galaxies. Luckily, there are dark patches in the sky which are devoid of foreground stars. These regions provide 'peepholes' to peer out of the Milky Way Galaxy. In December 1995, astronomers chose one of the peepholes located at a high galactic latitude in the direction of the Ursa Major (Great Bear) constellation, and zoomed in the Hubble Space Telescope to find out what lied out there. They were amazed to discover an assortment of more than 1,500 galaxies in various stages of evolution. These galaxies are billions of light-years away from the Earth. Among them, the most distant ones are thought to have formed about 13.2 billion years ago i.e. when the Universe was just about 500 million years old.
Every single object and shiny dot in the above picture is a distinct galaxy, probably containing billions of stars! Some of these galaxies look very different from the familiar elliptical and spiral shapes. This is because we are looking at galaxies of the early Universe. Just like an assortment of fossils, the above picture, known as The Hubble Deep Field (HDF), contains information about the Universe at many different stages in time. It can help us understand the evolution of galaxies over time. The tiny patch of the sky pictured above is considered representative of the typical distribution of galaxies in space. The area of the entire observable sky is millions of times greater than this tiny patch. You might also want to see these couple of space videos for some interesting thoughts on the Hubble Deep Fields.
In September 2003, astronomers again zoomed in the Hubble Space Telescope in a different direction (toward the Fornax constellation) to study a tiny patch of the sky that looks dark and empty from the Earth. Once again, a tiny dark patch of the sky revealed about 10,000 galaxies dating back to the early Universe. Astronomers called it The Hubble Ultra Deep Field (HUDF). It is shown in the picture above. It reveals the first galaxies that emerged shortly after the Big Bang, during a period called the dark ages of the Universe. Every single point of light visible in the above picture is a distinct galaxy. Each galaxy might contain billions of stars. The patch studied is so small that it would take 50 Ultra Deep Fields to cover the entire Moon, and millions of Ultra Deep Fields to cover the entire observable sky!
Some of the galaxies in the above picture look like toothpicks, some look like bracelet links, while others look like they are interacting. These are very odd shapes when compared to the familiar spiral and elliptical galaxies that we are used to seeing. The Universe might have been chaotic when these galaxies were formed. It might have been a period when order and structure were just beginning to emerge. The Hubble Ultra Deep Field can help us understand the birth and evolution of galaxies. When we look at it, we are looking back billions of years in time!
In September 2012, NASA released a picture of The Hubble eXtreme Deep Field (XDF) shown above. It is an improvement over the previous Hubble Ultra Deep Field. It shows about 5,500 extremely distant galaxies that formed in the early Universe. These galaxies are billions of light-years away from the Earth (see what is the radius of the observable Universe). As of 2013, the Hubble eXtreme Deep Field is the deepest image of the Universe ever taken. It reveals the faintest and the most distant galaxies ever seen by humans. The oldest galaxy found in the XDF existed just 450 million years after the birth of the Universe in the Big Bang.
The Hickson Compact Group 87 (HCG 87) is a group of galaxies located about 400 million light-years away from the Earth in the direction of the Capricornus (Capricorn) constellation. It consists of a spiral galaxy (top left), an elliptical galaxy (lower right), and a large edge-on spiral galaxy (lower left). The fourth galaxy, which is a small spiral galaxy visible near the center of the above picture, might be a background galaxy located far away. The bright stars visible in the picture are foreground stars from our own Milky Way Galaxy. The galaxies are gravitationally interacting in the group, and orbiting around a common center. They might take 100-million years (or even more) to complete one orbit.
The Spindle Galaxy (NGC 5866 or Messier 102) is a lenticular galaxy located about 44 million light-years away from the Earth in the direction of the Draco constellation. Its diameter is about 60,000 light-years. It is tilted edge-on toward us, as shown in the above picture of the galaxy. A subtle, reddish bulge surrounds its bright nucleus, and a blue disk of stars runs parallel to its dust lane.
NGC 1097 (Caldwell 67) is a barred spiral-galaxy located about 50 million light-years away from the Earth in the direction of the Fornax (Furnace) constellation. It is an active Seyfert Galaxy. A supermassive black hole, 100 million times as massive as our Sun is thought to be present in its core. When material falls into the black hole, the surrounding area emits powerful radiation. Due to inflow of material toward the central bar of the galaxy, the area surrounding the black hole is bursting with new star formation. It looks like a ring-shaped structure that has a diameter of about 5,000 light-years. The diameter of the entire galaxy is tens of thousands of light-years. It experienced three supernovae blasts between 1992 and 2003. It has two satellite-galaxies, out of which only one is visible in this close-up shot.
The above picture shows the Tadpole Galaxy (Arp 188), which is a barred spiral-galaxy located about 420 million light-years away from the Earth in the direction of the Draco (Dragon) constellation. The most peculiar feature of this galaxy is its 'tail,' which makes it look like a tadpole or a yo-yo. The length of this tail is about 280,000 light-years, which is more than two-and-a-half times the diameter of the Milky Way Galaxy. Astronomers think that a more compact intruder galaxy crossed in front of the Tadpole Galaxy, and the gravity of the former stretched a spiral arm of the latter to form the tail-like structure.
Mayall's Object is a pair of colliding galaxies located about 450 million light-years away from the Earth in the direction of the Ursa Major (Great Bear) constellation. It is named after Nicholas Ulrich Mayall, an American astronomer who discovered it in 1940. It is also called Arp 148 or VV 032. As shown in the above picture, the right galaxy has a ring-like shape, and the left galaxy looks like its tail. A previous collision between the two galaxies is thought to have created this peculiar shape. Interacting galaxies can collide several times before they merge together to form a single galaxy.
The above picture shows a rare and spectacular case of a triple-merger of galaxies that form a 'Tinker Bell' shaped structure. These interacting galaxies are called "ESO 593-8" or "ESO 593-IG 008." Astronomers also use names such as "The Bird," "The Tinker Bell Triplet," or "The Cosmic Tinker Bell" to refer to this system of interacting galaxies. They are located about 650 million light-years away from the Earth in the direction of the Sagittarius constellation. They consist of two spiral galaxies and a third irregular galaxy.
The 'wings' of this cosmic 'Tinker Bell' are about 100,000 light-years long, which is almost the length of the Milky Way Galaxy. New stars are being formed in the 'head,' at a rate of nearly 200 solar masses per year. Currently the 'head' and the 'body' of the 'Tinker Bell' appear to be moving apart at speeds exceeding 250 miles (400 kilometers) per second. However, the mutual gravity of the interacting galaxies might pull them back together and they might merge to form a single galaxy. The above picture released by ESO has been color-coded. For an optical picture of the Tinker Bell or 'The Bird,' see the following picture.
The above system of interacting galaxies (called ESO 593-8 or ESO 593-IG 008) looks like a bird in flight! Earlier astronomers thought that they were just two interacting galaxies, but recently a third interacting galaxy was found in the system. These triple interacting galaxies are located about 650 million light-years away from the Earth in the direction of the Sagittarius constellation. They are popularly known as "The Cosmic Tinker Bell" (see the previous color-coded picture), "The Tinker Bell Triplet," or simply "The Bird."
See also: Amazing Pictures of the Universe