A galaxy is a giant collection of stars, gas, dust, and dark matter, all gravitationally bound together. These celestial megalopolises can contain anywhere from a few thousand to trillions of stars, and stretch across millions of light-years. Our sun is just one star among billions in our home galaxy, the Milky Way.
Galactic Shapes
Galaxies come in a variety of shapes, with the most common being spiral, elliptical, and irregular. Spiral galaxies, like the Milky Way, have a flattened disk with spiral arms emanating from a central bulge. Elliptical galaxies are more oval-shaped and lack the defined structure of spirals. Irregular galaxies, as the name suggests, have no distinct shape.
A Universe of Galaxies
The number of galaxies in the universe is mind-boggling. Estimates range from a staggering 200 billion to a mind-blowing 2 trillion! These galaxies are constantly moving away from each other due to the expansion of the universe.
Our Galactic Home
We reside in the Milky Way galaxy, a barred spiral galaxy with a central bulge containing a supermassive black hole. Our solar system is located within one of the Milky Way's spiral arms, far from the crowded center.
Unlocking the Mysteries
Studying galaxies helps us understand the formation and evolution of the universe. Powerful telescopes like Hubble and the recently launched James Webb allow us to peer into these distant celestial wonders, unraveling their mysteries and searching for potential signs of life beyond our solar system.