All galaxies are held by gravity and consist of a massive amount of stars, interstellar gas and dust, leftovers from stars that have died, and dark matter, which scientists are still not completely sure of.
Galaxies are in many sizes and shapes, with the smallest having only around 10 million stars and the giants with hundreds of trillions of stars. With the help of high tech specialty telescopes, we have been able to estimate that there may be over 170 billion galaxies; but this is just in the areas of the universe that we have observed so far…there may be a lot more that we can’t see because their light is too dim.
The Sombrero galaxy is considered to be one of the most unusual of the barred spiral galaxies. The official designation of this galaxy is M104 or NGC 4594. As you can guess by the name, it is in the shape of the Mexican sombrero hat, and appears white and brilliant bright with a bulbous core that is surrounded by thick dust lanes that makes up the spirals. A dust lane is the location in a galaxy where stars are formed. This galaxy contains many areas that include all of the elements for being a star nursery. The halo that surrounds the disc is bigger than most and gives it the unique sombrero shape. Like most other galaxies, it’s believed that the Sombrero galaxy has a center that contains a massive black hole.
M104 is a distance of 28 million light-years away from us in the constellation Virgo. This galaxy can be seen with the help of small telescopes so that scientists can get a view of its mass which equals 800 billion suns. If that sounds large, it is. The Sombrero galaxy is one of the most massive galaxies in the Virgo galaxy cluster.
NASA astronomers have noted that the central bulge of the Sombrero galaxy display a lot of light points that are globular clusters. It also contains many detailed areas that scientists haven’t been able to identify. More recently, astronomers have revealed that the Sombrero galaxy has kind of a “split personality” that displays a large elliptical galaxy with a disk galaxy inside of it. They are not sure why this condition exists.
- Galaxy Type: Spiral
- Diameter: 50,000 light-years
- Mass: 800 M☉
- Constellation: Virgo
- Distance to Galactic Center: 29 million light-years
Some sources say that the Sombrero galaxy was discovered in 1781 by Pierre Méchain, renowned astronomer and comet hunter, who was also one of the associates of Charles Messier. Other sources indicate that it may have been Charles Messier or William Herschel who independently found the galaxy, although it had previously been discovered by others. Messier was creating a list of celestial objects that weren’t comets. His original records didn’t include M104, but later in 1781 he included it in his catalog. Pierre Méchain was surveying deep-sky objects and in a letter dated 1783, mentioned that he had located the galaxy. Herschel is most well-known as the individual who discovered the planet Uranus, had independently tracked the galaxy in 1784 during which time he noted the dust lane that surrounds the galaxy. Herschel did use larger telescopes than Messier.
A key discovery about this odd-shaped galaxy happened in 1912 when astronomers were still trying to figure out if what they were calling “spiral nebulas” were part of the Milky Way galaxy or completely separate. An astronomer at the Lowell Observatory named Vesto Slipher observed a “red shift” of 621 mi/1,000 km per second in the Sombrero. A red shift is the description of how an object’s light or spectra pattern becomes shifted to the red end of the spectrum as they move farther away from the Earth. This process stretches the wavelengths to the longer red ones. As they get closer to earth, they shift to the shorter blue-shift wavelengths. This is has become an important tool that is used to describe and monitor that universe’s expansion. The discovery of this red shift meant that M104 was probably outside of the Milky Way galaxy.
One of the first questions that anyone asks is why does the Sombrero galaxy look like a hat? There are a few reasons for the unusually extending and large bulge in the central area and the darker dust lanes that are in a disk when we look at it almost edge-on. Old stars can cause a diffused glow in the central bulge and the Sombrero has billions of these. If you get a closer view the bulge has a lot of points of light that are globular clusters. In other words, the center is packed so heavily with old stars that it has caused one area to bulge, creating something that looks like the top of a hat.
In 1996, the Hubble Space Telescope and the ground-based CFHT (Canada-France-Hawaii Telescope) discovered that the Sombrero galaxy most likely has a center with a supermassive black hole. The information was included in a 1997 publication where they included that “the gas and dust in this disk are swirling into what is most certainly a massive black hole.” It’s believed that the disk is the remnants of a collision with the Sombrero and a smaller galaxy hundreds of millions of years ago. Some scientist believe that these kinds of common collisions may be one way that the galaxies create quasars.
The human eye can’t see certain wavelengths so examining galaxies with technology that can view additional wavelengths can reveal data that would be hidden from us. Just looking at the Sombrero galaxy by using visible-light only kept astronomers from seeing the more spherical and elliptical shape of the galaxy. Viewing with visible-light only didn’t take into account the fact that old stars that made up most of the elliptical structure were very dim. When the Spitzer Space Telescope viewed the area with infrared light, the old stars popped with brightness and in 2012 this allowed the astronomers to re-classify the galaxy as an elliptical with an inside disk. It’s officially listed as an elliptical galaxy with a flat disk inside of it.
- The supermassive black hole in the Sombrero galaxy has star movement patterns that indicate that it could have a mass as large as a billion of our suns.
- Scientists believe that the supermassive black hole in the Sombrero galaxy may be the one with the most mass at the heart of any galaxy found so far.
- The Sombrero galaxy may have a huge mass but it is actually around 3/10 the size of our Milky Way galaxy.
- Astronomers don’t think that the Sombrero galaxy is part of any official or formal group of galaxies. They believe it’s part of a string of galaxies that stretch away from Virgo.
- Scientists believe that the Sombrero galaxy may contain as many as 2,000 globular clusters at its core. This would be 10 times the number of Milky Way clusters.
- On a very dark night without the intrusion of city lights, the Sombrero galaxy can be viewed through regular binoculars. Best time for viewing is the spring and early summer when it’s located between Virgo and Corvus.
- The Sombrero galaxy has a brightness or magnitude of nearing 9.0, which means that it can be seen with regular telescopes.
- The age of the Sombrero globular clusters are believed to be around the same age as the Milky Way’s: between 10-13 billion years old.
- Researchers studying the Sombrero galaxy have estimated that it has around 100 hundred stars for every human living on Earth. You can do the math by multiplying the 7 billion people that are alive.
- NASA uses both the Hubble Space Telescope and the Spitzer Space Telescope to study the Sombrero galaxy with visible and infrared light.
The Hubble Space Telescope has been a critical tool in resolving some of the problems and questions about the Sombrero galaxy. Using the telescope, scientists have discovered that the galaxy has a lot of globular clusters, estimated to be around 2,000, which is ten times more than in the Milky Way galaxy. The cluster ages are from 10-13 billion years old, which are close to the age of the clusters in the Milky Way. Inside the bright core of the Sombrero galaxy is a small tilted disk and X-ray emissions indicate that there is material that is falling into the core center where a supermassive black hole sits.
Scientists remain unsure of the origin of the Sombrero galaxy. Even though it has an unusual shape, they are finding that it isn’t unique in its kind. The Spitzer Space Telescope has helped astronomers view the infrared radiation of the cosmos. The discoveries of the Sombrero galaxy has caused them to question whether the Centaurus A galaxy, which is another galaxy close to the Milky Way may also be made up of two galaxies?
Facts about Sombrero Galaxy for Kids:
- The Sombrero galaxy is moving away from the Milky Way galaxy at a speed of 1000 km/s.
Scientists think that the nearing 2,000 globular clusters that live in the Sombrero galaxy core are a direct reason that the galaxy’s middle has such a large bulge.
- The Sombrero galaxy has the look of a Mexican hat because we are viewing it “edge-on” from Earth.
- The “hat” of the Sombrero galaxy is the dust lane which consists mainly of hydrogen gas and dust. This area holds most of the molecular cold gas in the galaxy and is the main area for the formation of stars.
- Scientists don’t think that many stars are formed in the nucleus of the Sombrero galaxy.
- The traits of the Sombrero galaxy include those of both elliptical and spiral galaxies. This is why it was so difficult for astronomers to figure out. By studying it they realized that it looked like an elliptical galaxy “swallowed” a spiral galaxy, which would not be possible because it would destroy the spiral galaxy.
- Scientists had to decide “how” the Sombrero galaxy’s shape occurred other than a spiral galaxy being swallowed by an elliptical one. They speculated that around 9 billion years ago a large elliptical galaxy collected lots of gas clouds that eventually flattened out into the spiral galaxy shape.
- The Sombrero galaxy has been used in a number of television shows, movies, and comics.
- A Silver Age minor character in the Superman DC comics is named “Vartox.” He claimed that he comes from the planet Valeron which is located in the “Sombrero Hat” Galaxy.
- The 1963 television series “Outer Limits” features a black-and-white photograph of the Sombrero galaxy at the ending credit of each of the original version episodes.
- In the 1957 sci-fi feature film by Jack Arnold called “The Incredible Shrinking Man,” the last voice-over by Grant Williams includes the Sombrero Galaxy along with other images and pictures that are supposed to reflect his thoughts on his future life, comparing the infinitely small to the infinitely large.