📖 what
What is the Hubble constant?
CosmologyExpansion
Quick Answer
The Hubble constant is the number that describes how fast the Universe is expanding per unit distance. It is usually given in kilometers per second per megaparsec.
The Full Story
The Hubble constant measures the present-day expansion rate of the Universe, linking a galaxy’s recession speed to its distance. It comes from Hubble’s law, based on observations first published in the late 1920s. Modern measurements disagree slightly depending on method, a tension known as the Hubble tension. Values are commonly near 67 to 74 kilometers per second per megaparsec, depending on whether they come from early-Universe or late-Universe observations.
Key Facts
1.It is expressed in km/s/Mpc
2.Current measurements show a well-known tension
3.Edwin Hubble’s work dates to the 1920s
YouTube Angle
Suggested video title for this topic:
"The number that tells us how fast the Universe is stretching right now"