"Dark energy, which most physicists have long held to be unchanging, may in fact be weakening."
"Since 1998, we've known that the expansion of the universe is accelerating. Dark energy is the name given to the accelerant. In the standard theoretical model of the cosmos, dark energy has a simple form: It is spread uniformly in space, maintaining a constant density at all times. Dark energy of this type, known as the cosmological constant, would not get diluted as the universe expands. Rather, as space grows, the amount of dark energy grows with it. And so this accumulating energy expands the universe with ever-increasing gusto."
"But the constancy of dark energy is merely a hypothesis, one that the Dark Energy Spectroscopic Instrument (DESI) experiment set out to check."
Analysis of 6.4 million galaxies "hints" that dark energy decreases with time.
The experiment isn't over and will run for 5 years, and will analyze 40 million galaxies. After that we should have a definitive answer.
Waning dark energy may evade 'swampland' of impossible universes | Quanta Magazine
