Have you ever wondered about how galaxies form and evolve? We live in the Milky Way Galaxy, one of 2+ TRILLION known galaxies in the observable Universe. Galaxies form and evolve over billions of years.
This is a LONG but easy to understand and insightful article written by an astrophysicist about his research into how galaxies form and evolve under the influence of dark matter. His ongoing research shows that galaxies seem to start out as "cosmic pickles" and evolve.
This computer simulation shows the evolution of particles representing stars. Note that after a number of stars have formed, the galaxy is “pickle” shaped—long, thin, and not rotating. A few satellite galaxies enter the visualization volume and merge with the central galaxy, but they do so along the main axis of the galaxy, so it continues to be long and thin. These images are all in the first (pre-"blue-nugget") stage of the evolution of this galaxy. Then the center becomes rounder and brighter, as gas flows toward the center and many stars form there (the "blue nugget" stage). Finally additional gas turns into stars to form a disk around the central region.
Simulation and video by Daniel Ceverino in collaboration with the author.
We can currently look back to the early Universe to about a billion years after the Big Bang and see young galaxies in their early stages of evolution. With new monster telescopes on the horizon we might be able to detect the very first galaxies to form!ex us
The enigmas of dark matter and dark energy still vex us as to what they are. We certainly can observe their effects on the Universe but are still in the dark - forgive the pun - as to what they truly are.
Perhaps one day we will know......
Sky Guy in VA