The Cosmic Expansion The universe is undergoing a large-scale expansion. This is evident in the redshift of distant galaxies, indicating they are moving away from us at a rate proportional to their distance. This phenomenon, described by Hubble's Law, suggests the universe is stretching like an inflating balloon. However, it’s crucial to understand that this expansion occurs at the level of galaxy clusters and superclusters, not within individual galaxies or their groups. Gravity counteracts this expansion on smaller scales. Galaxy clusters, bound together by the mutual gravitational attraction of their member galaxies, form relatively stable structures. The motion of galaxies within these clusters is primarily influenced by their gravitational interactions, not the overall cosmic expansion. Dark Matter: The Invisible Architect Dark matter, a mysterious substance detectable only through its gravitational influence, plays a pivotal role in cosmic structure. This non-baryonic matte...
“The universe is not only stranger than we imagine, it is stranger than we can't imagine”