The Hubble constant is named after the astronomer Edwin P Hubble, who astonished the world in the 1920s by confirming our universe has been expanding since it exploded into being 13.7 billion years ago.
In the late 1990s, astronomers discovered the expansion is accelerating, or speeding up over time. Determining the expansion rate is critical for understanding the age and size of the universe, NASA said.
NASA's Spitzer Telescope took advantage of long-wavelength infrared light to make its new measurement.
It improves by a factor of 3 on a similar, seminal study from the Hubble telescope and brings the uncertainty down to 3 per cent, a giant leap in accuracy for cosmological measurements.
The newly refined value for the Hubble constant is 74.3
