Galaxies are large groups of stars, dust, and gas. Galaxies contain planets, star system and clusters, and interstellar clouds. In between these objects, there’s a sparse interstellar medium of gas, dust, and cosmic rays. There are supermassive black holes located at the center of most galaxies. Supermassive black holes are the largest type of black hole. Galaxies that have less than a billion stars are considered “small galaxies”. Galaxies are categorized according to their shape. There are three types of galaxies, which are elliptical, spiral, and irregular galaxies.
Elliptical galaxies have very bright centers and little dust and gas. They’re born by the collision of many smaller galaxies. Their shape can range from spherical to flat. They can have tens of millions to over one trillion stars. The smallest elliptical galaxies (which are called “dwarf elliptical galaxy”) is about one tenth the size of the Milky Way galaxy! They’re also among the largest single star system in the Universe. They mostly contain old stars. Due to the little free-flowing gas, few new stars are form. They’re less frequently spotted due to them being dim and deader. The biggest galaxies are called giant ellipses.
Spiral galaxies have spiral arms and a bulge at the center. There’s a supermassive hole located at the very central bulge. The spiral arms are made of gas, dust, and new stars. They have a wealth of gas and dust. They’re the most common type of galaxy. Spiral galaxies have either arms that are wound tightly or loosely wound spirals. They can be used to classify spirals since it’s a genuine difference between the galaxies. The spiral arms are thought to be density waves. As stars move through a spiral arm, gravitational force modifies the velo...
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... than half the stars found in the galaxy are older than four point five billion years old. The Milky Way is as old as the universe itself.
There are probably more than one hundred billion galaxies. At a distance of approximately 13.1 billion light years, z8_GND_5296 is the most distant galaxy yet discovered. The galaxy appears to astronomers as it was just seven hundred years after the big bang. What’s used to observe galactic phenomena are ultraviolet and x-ray telescopes. An ultraviolet flare was observed when a star in a distant galaxy was torn apart due to the tidal forces of a black hole. X-Rays can map the distribution of hot gas in galactic clusters. No one knows the exact number of galaxies there is, or if the universe has an end. One can travel at the speed of light forever without reaching an edge since the universe is without a boundary and is expanding.
Clusters like NGC 6530 were formed from the same cloud, and as a result have roughly the same age. This makes them of particular interest to astronomers. Because clusters are all formed from the same material, have roughly the same age, and distance from earth, variations in their brightness is only due to their mass ("Open Star Clusters"). This makes them particularly useful for studying stellar evolution. This cluster was first observed by Hodierna in 1654, and later found independently by Flamsteed in 1680 when he discovered the cluster was located within the Lagoon Nebula. Like most open star clusters, NGC 6530 is relatively young; having been formed less than 6 million years ago ("Young Stars Paint Spectacular Stellar Landscape"). It is known to consist of more than a hundred known bright stars, the light of which show very little reddening as a result of interstellar matter from the nebula, this is likely because the cluster is located just in front of the
Two men named Harlow Shapley and Heber Curtis has a debate in 1920 that is still important today for changing how we think about galaxies. They talked about five important things. The first thing they debated was how big our galaxy, the Milky Way, is. Shapley said that the Milky Way was much bigger than we first thought, 100,000 light-years across, and that, because it was that big, it had to be the only one. Curtis said the the Milky Way was smaller than that, and that other galaxies existed past ours. They were both right and both wrong. Shapley was right about the size of the Milky Way, and Curtis was right about there being many more galaxies in the universe.
Waller, William H. The Milky Way: An Insider's Guide. Princeton, N.J: Princeton UP, 2013. 42+. Print.
A nebula is a space dust that appears as a hazy bright, colorful patch in the sky. The Orion Nebula goes way back from millions of years ago and is made up of mostly hydrogen, but also helium, carbon, nitrogen, and oxygen (Wiley 1). The Orion Nebula is also known as M42, Messier 42, and NGC 1976 (Ivan P. 1). Even though the Orion Nebula may have a giant black hole in the middle of it, The Orion Nebula is still the brightest nebulae because it can be seen with the naked eye during certain times of the year and has the three brightest stars in it.
However, galactic interactions do often share many characteristics. The most notable feature associated with interacting galaxies is often the “starburst” phenomenon. A starburst is an extremely high rate of star formation over part or all of a galaxy over a cosmologically short period of time (possibly a few billion years as opposed to several billion years). Galaxy interactions cause gravitational instabilities in interstellar gas clouds, which compress the gas in the clouds and trigger star formation (Mouri 2003). When astronomers look at an ongoing starburst in a distant galaxy, they see the starburst as a bluer region than the surrounding parts of the host galaxy. That is due to the extremely hot and energetic, yet short lived, O-type stars produced in the burst, which outshine all of the other stars being born around them as well as the older, redder stars that populate the galaxy.
Black Holes are mostly found inside of the Milky Way. There are many types of galaxies and many different types of Black Holes. A normal galaxy has gases and stars
The extreme brightness of the O-type and B-type stars, coupled with the Earth’s atmosphere, has always made high-resolution imaging of the star-forming region difficult. But recent advances in adaptive optics and the repair of the Hubble Space Telescope have allowed for incredible detail into the center of the dust cloud. 3 The technological advances have also helped reveal several faint stars within the center of the nebula.
The many minor members of the solar system are the asteroid and comet. The asteroid is a small, rocky body that orbits the Sun. A large number of these, varying greatly in size, can be found as an asteroid belt. There is an asteroid belt between the orbits of Mars and Jupiter. A comet is a small object made up of ice and dust, and when it's near the sun, it has a thin, fuzzy, temporary atmosphere. It also has a tail of gas and dust particles that faces away from the sun.
By 1936, astronomers had realized that the hazy balls they sometimes saw in their telescopes, which looked like stars obscured by gas, were actually galaxies (Hibbison).
In modern day physics, Black Holes have dominated the spotlight for quite some time. While the concept has answered many questions, it has also introduced hundreds more. There is believed to be a black hole at the center of our galaxy, the Milky Way galaxy. Black holes were first proven to exist in the 1970’s when a few scientists identified a black hole called Cygnus X-1. Since then, an intense amount of study has been dedicated to discovering the various properties of black holes.
Supermassive black holes and the galaxy can be compared to the Sun and the solar system.(Smith, Heather R.) Without the Sun pulling on the planets they would float off into the galaxy. If there isn't a black hole pulling on all the stars and planets in the galaxy there will be no galaxy. Sagittarius A is like the Sun on an enormous scale. Sagittarius A alone is suspending over 200 billion stars. With the Universe said to be scattered with 300 billion galaxies,(Vergano, Dan) and a black hole at the center of each and every one, it is safe to say black holes are the suspenders of the Universe.
As you can see we have been temporarily blinded from the truth by fictional things that are easy to believe and that we want to believe. There are so many incorrect theories and ideas and most of them are just plain ridiculous. Astronomy can be a very complicated subject, but it is very necessary to understand what really happens in our galaxy and out in the huge frontier we call space.
The Universe is a collection of millions of galaxies and extends beyond human imagination. After the big bang, the universe was found to be composed of radiation and subatomic particles. Information following big bang is arguable on how galaxies formed, that is whether small particles merged to form clusters and eventually galaxies or whether the universe systematized as immense clumps of matter that later fragmented into galaxies (Nasa World book, 2013). A galaxy is a massive area of empty space full of dust, gases (mainly 75% Hydrogen and 25%Helium), atoms, about 100-200 billion stars, interstellar clouds and planets, attracted to the center by gravitational force of attraction. Based on recent research, 170 billion galaxies have been estimated to exist, with only tens of thousands been discovered (Deutsch, 2011).
Black holes are one of the many amazing unexplainable wonders around the world. Black holes are also very abundant in many galaxies especially the Milky Way. There is believed to be at least over ten million black holes scattered around the Milky Way galaxy alone. In every galaxy there is a supermassive black hole that is at least billions of times as big as the sun and it is big enough to swallow the whole solar system.
Two galaxies which are believed to revolve around our own are the Small and Large Magellanic Clouds. Only visible from the Southern Hemisphere, Magellan, the famous European explorer, was the first to describe these galaxies. Even though we know a great amount more than the astronomers in the past, there is still an even larger amount we do not know about the universe to this day. Even our own solar system contains many questions yet to be answered. Some of these include the possibility of a planet beyond Pluto (Planet X), the means by which the system was created, and even the possibility of a sister star to the Sun named Nemesis.