Melkweg

The Milky Way is the galaxy that contains the Solar System. In Dutch, the term melkweg refers to this same galaxy, highlighting its characteristic band of light across the night sky. The Milky Way is a barred spiral galaxy with a diameter of about 100,000 light-years and a thick disk that hosts hundreds of billions of stars, as well as vast quantities of gas, dust, and dark matter. Estimates for the total stellar population range from 100 to 400 billion stars.

Its structure comprises a central bulge, a flattened disk with spiral arms, and a surrounding halo. The disk contains distinct spiral arms and a young, active star-forming ring in the inner parts. The Milky Way's central region houses a dense bulge and a supermassive black hole at Sagittarius A, with a mass of about 4 million solar masses.

Location of the Solar System: The Sun is located in the Orion Arm, roughly 27,000 light-years from the Galactic Center, orbiting at about 220–240 kilometers per second and taking about 225–250 million years per orbit.

Observational aspects: Much of the galaxy lies beyond visible clarity due to interstellar dust. Infrared and radio observations, including the 21-centimeter line of neutral hydrogen, reveal the structure and kinematics of the Milky Way. The galaxy has satellite dwarf galaxies, notably the Large and Small Magellanic Clouds, and other satellites.

Context: The Milky Way is part of the Local Group of galaxies, within the Virgo Supercluster and the Laniakea supercluster. It formed around 13.6 billion years ago and continues to evolve, with ongoing star formation and interactions shaping its future, including a predicted future collision with the Andromeda Galaxy in several billion years.