What are Galaxies?
Space is very large and can be mind-boggling to grasp how big it really is; the fact that it is constantly increasing in size does not aid us either. Everything you can think of of lies in space; it is also commonly known as the Universe. To make it slightly easier for us to examine the Universe, all things inside it are arranged like folders in one huge drawer – think of the Universe as this drawer. The largest group in the universe are Galaxies; imagine these as massive folders. It gives the Universe a cosmic structure.
Thanks to the amazing Hubble telescope, the Universe is estimated to contain a staggering 100 billion galaxies. Let’s delve closer in to our galaxy named the Milky Way; it is classed as a special type of spiral galaxy: a barred spiral galaxy due to its center having an appearance of a bar consisting of numerous stars. This typically has a bulge at its core which is a composition of close-bound old stars; roughly two-thirds of spiral galaxies are barred and many spirals can also contain black holes in their center. Why is it a spiral? Well, all existing matter in this galaxy entities rotates around the galaxy’s center just like the Earth rotates around the Sun and this rotation is due to gravity. A fun fact: it takes approximately 240 million years for one full Milky Way orbit.
Elliptical galaxies is the next classification and have an oval shape in appearance. It is believed that the center of these galaxies is a black hole. Dust and gas are paramount in creation of new stars; this galaxy lacks in both therefore the amount of stars being born is minimal.
The final category is irregular which entails gas and dust which is the perfect recipe to create new stars. It is named this because it’s structure has no regularity – it is just a randomly organised lump.
Entities in the milky Way rotate around the galaxy’s center just like the Earth rotates around the Sun; in more detail it takes approximately 240 million years for one full Milky Way orbit.