Galactic structure refers to the organization and arrangement of matter within a galaxy, including stars, gas, dust, and dark matter. The Milky Way, for example, is a barred spiral galaxy characterized by its distinct spiral arms and a central bulge, which houses a dense concentration of stars and possibly a supermassive black hole like Sagittarius A*. Understanding galactic structure helps astronomers learn about the formation and evolution of galaxies over time. Different types of galaxies, such as elliptical and irregular galaxies, exhibit unique structures and characteristics, providing insights into the processes that shape the universe, including dark energy and cosmic inflation.