Cosmic Expansion Outpaces Light Without Violating Physics
The universe’s expansion allows distant galaxies to recede faster than light while local light-speed limits remain intact, making the observable universe extend about 45 billion light-years even though it’s 13.8 billion years old. Objects’ recession is traced by redshift, with a cosmological event horizon around 17 billion light-years that will never be crossed by light from beyond it; as dark energy accelerates expansion, this horizon grows toward ~60 billion light-years, and in roughly 100 billion years, galaxies beyond the Local Group will vanish from view.
