Data from NASA’s JSWT confirms the Hubble Space Telescope's earlier finding that the rate of the universe's expansion is faster by about 8%.

Universe’s Expansion Rates:

• Hubble’s Law — also known as the Hubble Constant — says that universe is expanding at a rate of 67-68 kilometers per second per megaparsec (a megaparsec is 3.26 million light-years). 
• However, telescope observations give a higher value of 70 to 76 kilometers per second per megaparsec.
  • This discrepancy between the telescope observed expansion rate of the universe and the Hubble Constant is called the ‘Hubble Tension’ 

Probable reasons for expansion:

• Dark matter: Comprise ~ 27% of the universe, is a hypothesised form of matter that is invisible but is inferred to exist based on its gravitational effects on ordinary matter like stars, planets, moons, etc.
  • Ordinary matter accounts for roughly 5% of the universe.
• Dark energy: It’s a hypothetical form of energy proposed by physicists to explain why the universe is not just expanding but is doing so at an accelerating rate.
  • It comprises ~69% of the Universe.
  • It’s an anti-gravity" force that stretches the very fabric of spacetime.