Distant galaxies' apparent superluminal speed comes from cosmic expansion
Updated
Updated · Big Think · May 1
Distant galaxies' apparent superluminal speed comes from cosmic expansion
5 articles · Updated · Big Think · May 1
Ethan said galaxy MoM-z14, at redshift 14.44 and about 33.8 billion light-years away, appears to recede faster than light only because space itself expands.
He said special relativity alone cannot explain such distances, while general relativity and redshift-distance measurements, including brightness and angular-size tests, match an expanding universe.
The column said this does not break physics or require infinite Big Bang energy; most extreme redshifts reflect cosmic expansion, despite a 9% Hubble tension over today's expansion rate.
Could resolving the Hubble tension reveal new laws of physics or hidden aspects of cosmic expansion?
If galaxies aren't moving through space faster than light, what exactly is expanding—and could this expansion ever stop or reverse?
How might future discoveries with gravitational waves or the Roman Space Telescope challenge our understanding of the universe’s true size and age?
Hubble Constant at 70-73 km/s/Mpc: Confirming the Universe’s Accelerating Expansion and Its Implications
Overview
Recent precise measurements from the James Webb and Hubble Space Telescopes confirm the local expansion rate of the universe is between 70 and 73 km/s/Mpc, significantly higher than the 67.4 km/s/Mpc value derived from early-universe data by the Planck mission. This 4- to 7-sigma discrepancy, known as the Hubble Tension, is unlikely due to measurement errors and suggests gaps in the standard cosmological model. Dark energy, driving the universe's accelerating expansion, may be evolving, challenging existing theories. New methods, including gravitational wave observations and upcoming missions, aim to resolve this tension, which is crucial for understanding the universe's ultimate fate and the nature of cosmic expansion.