Another fascinating aspect of astronomical studies that I keep pondering over is the formation of galaxies. Ever since we stepped into school, we’ve been taught about the solar system and how the different planets revolve around the sun in elliptical orbits, as well as rotate on their own axis. Then we have the satellites orbiting the planets and finally the different asteroids, comets, meteors and meteorites, to name a few. But what most education bodies tend to ignore here is to encourage students to ask questions about how all of this was formed in the very first place. Yes, there is no single consensus regarding the same and there are several theories that attempt to explain the sheer wonder of galaxy formation and patterns. Here’s a brief look at both of them:-
Top-Down Theory of Galaxy Formation– Please note that this is not a single theory but a bunch of theories that follow a similar pattern and are more or less linked to each other. The simplest way to explain would be to ask you to visualize a pizza dough ball that is spinning at high speed. This is exactly what happened when certain particulate matter of the universe got clumped together owing to gravitational forces. Then these acquired collective momentum like a spinning ball of dough and gradually rifted apart, but still orbiting around one another.
Bottom Up Theories on the other hand propose that the formation of the galaxies happened owing to the breakdown of large gas clouds that inhabited the universe trillions of centuries ago. There was possibly formation of galaxies from these smaller clouds, which were formed when the large clouds burst. Since I cannot find a pizza dough equivalent to explain this concept to you, please try to understand on your own.
P.S- The above theories only attempt to explain the formation of disk-shaped galaxies. There are so many other shapes that still warrant other theories of explanation. Will try to mention them in upcoming posts, if you have the time and inclination to read, for sure!