KOMPAS.com – A galaxy, simply put, is a vast collection of gas, dust and billions of stars and their solar systems, all held together by gravity.
The Earth that humans live on is part of the solar system, which is a small part of the Milky Way galaxy.
Quoted from the Britannica page, a galaxy is a system of stars and interstellar material that forms the universe.
Galaxies consist of dust, gas, dark matter, and millions to trillions of stars held together by gravity.
Also read: It’s Not the Sun, It’s the Hottest Place in the Universe
Nearly all galaxies appear to have been born soon after the universe formed, and they were scattered across space.
The first stars in the universe appeared about 180 million years after the big bang, the moment that marked the origin of the universe.
Gravity then formed the early galaxies when the universe was 400 million years old.
Galaxies usually exist in groups, some of which are grouped into larger groups that are hundreds of millions of light years across.
The shapes of galaxies differ from one another, with variations resulting from the way the systems form and then evolve.
Also read: Getting to Know the Supernova Phenomenon and What Happens Afterwards
Types of galaxies
Unsplash/Bryan Goff
Illustration of the Milky Way galaxy.
Reporting from the National Geographic page, galaxies can be grouped into four main categories, namely:
1. Spiral galaxy
Spiral galaxies have a flat rotating disk with a central bulge surrounded by spiral arms.
The rotating movement at a speed of hundreds of kilometers per second can cause the material in the disk to take a distinctive spiral shape, like a cosmic pinwheel.
The Milky Way, where the Earth and its solar system are located, is an example of a spiral galaxy. It has a starry linear bar at its center.
Also read: Temperature Reaches Minus 272 Degrees Celsius, Where is the Coldest Place in the Universe?
2. Elliptical galaxy
Elliptical galaxies are generally round but can stretch longer on one axis than the other.
The largest known galaxies in the universe, giant elliptical galaxies, can accommodate up to a trillion stars and stretch as far as two million light years.
However, this type of galaxy can also be small, so it is called a dwarf elliptical galaxy. This galaxy has little dust and interstellar material.
Also read: The 5 Most Famous Space Flight Accidents in History
3. Lenticular galaxies
Lenticular galaxies, such as the Sombrero Galaxy, have a shape somewhere between an elliptical and a spiral galaxy. It is called “lenticular” because it resembles a lens.
Like spiral galaxies, this type has a thin, rotating disk of stars and a central bulge, but no spiral arms.
And like elliptical galaxies, they have little dust and interstellar matter, and appear to form more often in densely populated regions of space.
Also read: How was the Earth Formed 4.5 Billion Years Ago?
4. Irregular galaxies
Irregular galaxies, such as the Large and Small Magellanic Clouds that flank the Milky Way galaxy, appear to have no clear shape.
Often because these galaxies are under the gravitational influence of other nearby galaxies.
They are full of gas and dust, making them great breeding grounds for the formation of new stars.
Get selected news updates and breaking news every day from Kompas.com. Let’s join the Telegram Group “Kompas.com News Update”, by clicking the link https://t.me/kompascomupdate, then join. You must install the Telegram application first on your cellphone.
2023-12-20 02:30:00
#types #galaxies #universe #Milky #include #Kompas.com
