Key points about the Milky Way:
Size and Structure:
It spans about 100,000 light-years across and is made up of over 100 billion stars. The galaxy is divided into a bulge at the center, spiral arms, and a halo of older stars and globular clusters.
The Center:
The center of the Milky Way contains a supermassive black hole called Sagittarius A*, which is about 4 million times the mass of the Sun. It’s the powerhouse at the galaxy’s core.
Our Solar System:
Our Sun and solar system are located in one of the spiral arms, known as the Orion Arm. We’re about 27,000 light-years from the galactic center.
Motion:
The Milky Way is not stationary. It is rotating, and the stars, including our Sun, orbit the center. The Sun takes about 230 million years to complete one full orbit, a journey known as a cosmic year.
The Local Group:
The Milky Way is part of a group of galaxies called the Local Group, which includes over 50 galaxies, with the Andromeda Galaxy being the largest member. The Milky Way and Andromeda are on a collision course and are expected to merge in about 4.5 billion years.
Exploration:
We can’t travel beyond our galaxy yet, but astronomers study the Milky Way using telescopes like the Hubble Space Telescope and the James Webb Space Telescope. These tools help us understand the galaxy’s structure, formation, and the types of stars and planets within it.
Dark Matter:
The Milky Way, like most galaxies, contains a lot of dark matter—an invisible form of matter that doesn’t emit light but exerts gravitational pull. It helps explain why galaxies rotate the way they do and why the Milky Way holds together despite the outward forces from rotation.