The most beautiful galaxies in the universe
Our universe is a place that is both terrifying as it is wonderful, and fascinating as it is strange.
Astronomers estimate that there are between 100,000 and 200,000 million galaxies in the universe that we can observe. They have three distinct configurations: they can be elliptical, spiral, and irregular. This classification system was developed by the American astronomer Edwin Hubble, based on the shape of galaxies and on their visual appearance and not on other aspects such as the activity of the galactic nucleus or the rate of stellar formation.
The Milky Way, for example, is a spiral type (spiral arms are its most characteristic quality), it’s 13.2 billion years old and has a diameter of 100,000 light-years. The disk of our galaxy is far from perfectly flat; in fact, as can be seen in many images, it is deformed. A characteristic that astronomers attribute to our galaxy's two neighbours, the large and small Magellanic clouds.
The Milky Way also has a halo. Scientists believe that 90% of the mass of our galaxy consists of dark matter. In this case, the halo is really invisible, but its existence has been demonstrated by running simulations of how the Milky Way would appear without this invisible mass.
The galactic halo, which is about 15 kiloparsecs in size, is believed to consist of sparsely dense interstellar gas, ancient stars and dark matter.
Our solar system is approximately 27,000 light-years away from the Galactic Center, at the inner edge of one of the spiral-shaped concentrations of gas and dust particles called Orion's arm.
In general, our universe is a wild place and, throughout human history, many a man has tried to make sense of it. Although we have come a long way in our understanding of the cosmos, with new discoveries almost every day, we still have a lot to discover and a lot to find out.
To get a closer look at one of the most beautiful objects in the universe, we will make a galactic journey from our Milky Way to other galaxies such as the galaxy of the Hat, Andromeda, our neighbour (with which we will collide in 4,000 million years, creating what has been called the Lactameda), or the galaxy of the Tadpole.
This image captured by the NASA/ESA Hubble Space Telescope is a colourful whirl called NGC 6753: the blue explosions in the spiral arms are regions filled with young stars that shine brightly in ultraviolet light, while the redder areas represent older stars. This galaxy is 150 million light-years away from Earth. According to astronomers, it is one of only two known spiral galaxies, large enough and close enough to allow detailed observations of its crowns. They are very faint, emitting in X-rays, hence they are extremely difficult to detect.
Image credit: ESA/Hubble & NASA
Our galaxy - the second largest in the Local Group - has a mass of 10^12 solar masses and, as we already know, is a barred spiral galaxy. Its average diameter is estimated at about 100,000 light-years and houses between 200,000 and 400,000 million stars. From the centre of the galaxy to our star, the Sun, there are about 25,766 light-years.
Image credit: NASA
The protagonist of this NASA / ESA Hubble Space Telescope image is a galaxy known as NGC 4656 or galaxy hockey stick. It is located in the constellation Canes Venatici. Although its name is confusing due to this partial view, the fact is that the galaxy has the shape of an elongated and deformed stick, which extends through space until rolled up at one end to form a surprising imitation of a celestial hockey stick. This unusual shape is due to an interaction between NGC 4656 and a pair of near neighbours, the NGC 4631 and the NGC 4627. These galactic interactions can completely transform a celestial object, displacing and deforming its gas, stars and dust into forms as strange and beautiful as this one.
Image credit: ESA/Hubble & NASA
The Large Magellanic Cloud is a dwarf galaxy, also a member of the Local Group. It is 160,000 light-years from Earth; it is 'so close' that it is visible to the naked eye as a faint object in the Earth's southern hemisphere located between the constellations of Dorado and Mensa. The Portuguese explorer Fernando de Magallanes was the first to discover the existence of this galaxy, hence its name.
Image credit: Axel Mellinger, Central Michigan Univ.
NGC 4248 is a spiral galaxy located in the constellation of the Canes Venatici, about 25 million light-years away from Earth. In this image, captured by the Wide Field Camera 3 of the NASA/ESA Hubble Space Telescope, we see a beautiful group of glowing gas, dark dust and bright stars: the spiral galaxy NGC 4248.
Image credit: ESA/Hubble & NASA
Discovered by British astronomer William Herschel more than 200 years ago, the galaxy NGC 2500 is about 30 million light years from Earth in the northern constellation Lynx. As this NASA / ESA Hubble Space Telescope image shows NGC 2500 is a particular type of spiral galaxy known as a barred spiral, in which its faint arms swirl from a bright, elongated core. This galaxy is still actively forming new stars, although this is a somewhat uneven process because as we can see in this image, the upper half of the galaxy hosts many more star-forming regions than the lower half (much fainter).
Image credit: ESA/Hubble & NASA
The Andromeda galaxy is 2.537 million light-years away from Earth in the constellation Andromeda. Its 'closeness' to our planet makes it the most distant object visible to the naked eye on Earth. It is the nearest giant galaxy and contains approximately the same number of stars as the Milky Way.
Image credit: NASA
Although the galaxy IC 342 is very bright, it is near the equator of the galactic disk of the Milky Way, where the sky is filled with dark cosmic gas, stars and dark dust; so to see this intricate spiral structure, astronomers must look through a large amount of material contained within our own galaxy, which is not easy at all. Hence it is nicknamed the 'hidden galaxy'. It is 10.7 million light years from the Milky Way.
Image credit: ESA/Hubble & NASA
NASA/ESA's Hubble Space Telescope has captured this image of the galaxy known as ESO 486-21: a spiral galaxy, albeit with a somewhat irregular and ill-defined structure, located about 30 million light-years away from Earth. This cosmic object is in the middle of the process of forming new stars (in the large clouds of gas and pinkish dust in the image).
Image credit: ESA/Hubble & NASA
There are approximately 51 galaxies in the local Group, as the Cigar galaxy is one of the most prominent along with Andromeda or the Great Magellanic Cloud. It is an elongated and narrow irregular galaxy located in the constellation of the Ursa Major about 12 million light years away from Earth. It has a high volume of star formation in the centre, with a formation rate of 10 solar masses per year, and a size of 500 parsecs. A supernova is produced every 10 years.
Image credit: NASA
The great majority of cosmic objects that appear in astronomical catalogues are given little poetic names based on the order of their discovery, such as some of the galaxies that we have already visited in this photo gallery.
In this Hubble space telescope image, the largest of the galaxies is NGC 4424. Just below is LEDA 213994, which refers to the extragalactic Lyon-Meudon (LEDA) database, much more modern than NGC. Leda, according to Greek mythology, was one of the women seduced by Zeus.
Image credit: ESA/Hubble & NASA
The beautiful spiral galaxy visible in the centre of the image captured by the NASA/ESA Hubble telescope is known as RX J1140.1 + 0307, a galaxy located in the constellation Virgo that has curious qualities. At first glance, it appears to be a normal spiral galaxy, much like the Milky Way, but appearances are deceptive. RX J1140.1+0307 contains a great enigma. The galaxy has in its centre one of the black holes of smaller mass known of all those that reside in luminous galactic nuclei. Scientists are puzzled because the calculations about its mass do not match those about its other characteristics.
Image credit: ESA/Hubble & NASA
Located 25 million light years away from Earth in the constellation of the Great Bear, the Molinete galaxy or NGC 5457, is one of the largest galaxies in our Milky Way neighbourhood (more than twice the diameter of our galaxy). One of its curiosities is that it does not seem to have a black hole in its centre.
Image credit: NASA
More than a century after the discovery in 1900 of galaxy IC 5201, is still of interest to astronomers. It is more than 40 million light-years away from Earth, in the constellation The Crane. This galaxy, like most of the spiral galaxies we see in the Universe, including the Milky Way, has a barrier of stars that crosses its centre.
Image credit: ESA/Hubble & NASA
The constellation Virgo hosts many galaxies, one of which is NGC 4388, which is about 60 million light years away from Earth. According to observations captured by NASA/ESA's Hubble Space Telescope, this galaxy is undergoing a transformation and has acquired a somewhat confusing identity, as the outside of the galaxy looks smooth but its centre shows noticeable dust lines limited by two symmetrical spiral arms, emerging from the galaxy's resplendent nucleus. Despite this confusion, NGC 4388 is classified as a spiral galaxy.
Image credit: ESA/Hubble & NASA
The Sombrero galaxy is about 28 million light-years away from Earth in the constellation Virgo. The reasons why this galaxy looks like a hat are: the unusually large central bulge of stars, and the dark, prominent lines of dust appearing on a disk that we see almost by song. The diffuse brightness of the central bulb is also due to billions of ancient stars.
Image credit: NASA
This delicate group of blue stars is actually an irregular galaxy called IC 3583, located about 30 million light years away from Earth in the constellation Virgo. This small galaxy is believed to be interacting gravitationally with one of its neighbors, the spiral galaxy Messier 90. Together, they form the pair known as Arp 76.
Image credit: ESA/Hubble & NASA
Thanks to new observations from the NASA/ESA Hubble Space Telescope, astronomers have discovered the intricate structure of the galaxy NGC 4696 in more detail than ever before. The elliptical galaxy, located in the constellation Centaurus, is a cosmic rarity with a bright nucleus wrapped in a system of dark, spiral-shaped filaments.
Image credit: ESA/Hubble & NASA
Located about 35 million light-years from Earth, the Whirlpool galaxy is one of the brightest galaxies in our night sky, visible with simple binoculars. It is a spiral galaxy located in the constellation Canes Venatici.
Image credit: NASA
In this NASA/ESA Hubble Space Telescope image, we see the spiral galaxy NGC 3274 discovered in 1783 by astronomer William Herschel. It is a relatively weak galaxy located more than 20 million light years away from Earth in the constellation Leo. This image also shows galaxy PGC 213714 in the upper right-hand corner, farther away from Earth.
Image credit: ESA/Hubble & NASA
The galaxy of Bode or Messier 81 is a spiral galaxy located 12 million light years away from Earth in the constellation of the Ursa Major. Its name comes from the German astronomer Johann Elert Bode, who discovered it in 1774. It is believed to contain about 250,000 million stars and, along with its companion the Cigar galaxy, you can locate them in the same field of view for most telescopes. And, in favorable conditions, that is, without light pollution and with a dark and clear sky, it is possible to observe them with the naked eye.
Messier 64, or the Black Eye galaxy, is a spiral galaxy located in the constellation Coma Berenice about 17 million light-years away from Earth. Also known as the "evil eye galaxy" or "devil's eye", it is famous for the dark band of dust in front of the bright nucleus of the galaxy (hence its nickname). Messier 64 extends through space covering an area almost 40,000 light-years in diameter, spinning at a speed of 300 kilometres per second. The galaxy can be observed with small telescopes.
Image credit: NASA
Formally known as Messier 63, the sunflower galaxy seems to belong to the repertoire of works by the great Vincent Van Gogh. This cosmic beauty has bright, sinuous arms formed by newly formed blue and white giant stars.
It was discovered by Pierre Méchain in 1779 and is 27 million light years away from Earth in the constellation of Canes Venaciti (hunting dogs).
Image credit: NASA
MACS J0717 is one of the strangest galaxies (astronomically speaking) we can find in the cosmos. Technically, it is a cluster of galaxies that was formed by the collision of four other clusters. As we can see in this NASA image, the galaxy cluster MACS J0717 is one of the most complex and distorted galaxies known. It is about 5.4 billion light years away from Earth and covers more than 13 million light years.
Image credit: X-ray: NASA/CXC/SAO/van Weeren et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA
Messier 74 was discovered in 1780 by Charles Messier's observation assistant, the French astronomer Pierre Méchain. This spiral galaxy is about 30 million light years from Earth in the constellation Pisces. It is a perfect example of a highly designed spiral galaxy. The symmetrical spiral arms extend from the central core of the galaxy via tortuous dust lanes. The arms are dotted with clusters of young blue stars and pink regions where the ultraviolet light from these young stars has ionized clouds of hydrogen and made them shine.
Image credit: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration; Acknowledgment: R. Chandar (University of Toledo) and J. Miller (University of Michigan)
Galaxy I Zwicky 18, identified in the 1930s by astronomer Fritz Zwicky, is one of the strangest galaxies in the universe. Astronomers are still confused about it, as it shows the development of stars typical of galaxy formation since the early days of the universe. It is only 500 million years old, it is practically a newborn galaxy, in which its stars are composed almost exclusively of hydrogen and helium. This irregular galaxy is 45 million light-years away from Earth.
Image credit: NASA, ESA, and A. Aloisi (Space Telescope Science Institute and European Space Agency, Baltimore, Md.)
The IDCS 1426 galaxy cluster is the most massive in the early universe. It is 10 billion light-years away from Earth and weighs the equivalent of 500 billion suns. Its distance is such that the light detected corresponds to when the universe was about a quarter of its current age.
Some 600 million years ago, there was a collision between galaxies NGC 4038 and NGC 4039, starting a massive exchange of stars and galactic matter between the two structures. Scientists named it as it is because its figure resembles an antenna. These galaxies were discovered in 1785 by William Herschel. When they fuse completely, in many years, it will become an ultra-luminous infrared galaxy.
NGC 6744 is a large spiral galaxy. Astronomers believe that it is one of the most similar to ours, the Milky Way. Located about 30 million light-years away from Earth in the constellation Turkey, the galaxy's elongated nucleus and swollen arms are quite reminiscent of our home, don't they?
Messier 77 is a barred spiral galaxy located about 47 million light years away in the constellation Cetus. It is one of the largest galaxies in the Messier catalogue as its weakest extensions reach nearly 170,000 light years. If you want to look for it in the sky, this galaxy is easy to see even with small telescopes, it will appear as a blurred round spot near a star of magnitude 10.
