AI Insight
For nearly a century, astronomers have observed the universe's expansion, but in the late 1990s, two independent research teams discovered that this expansion is accelerating rather than slowing down. This unexpected finding, which earned the 2011 Nobel Prize in Physics, led to the prevailing explanation of "dark energy" - a mysterious force pushing space apart. This discovery forms the basis of the LCDM model, which has been the standard cosmological framework for understanding the universe for the past 25 years.
Why it matters
Understanding dark energy and the universe's accelerating expansion is fundamental to determining the ultimate fate of the cosmos and our place within it. This research challenges our basic understanding of physics and may require new theories beyond our current models of gravity and spacetime.
Understand the Science
For nearly a century, astronomers have known that the universe is expanding. In the late 1990s, two independent teams, the Supernova Cosmology Project, led by Saul Perlmutter, and the High-Z Supernova Search Team, led by Brian Schmidt and Adam Riess, discovered something strange: The expansion is speeding up. The finding earned them the 2011 Nobel Prize in Physics. The leading explanation for this acceleration is “dark energy,” a mysterious force usually modeled as a constant called Lambda, pushing space apart. Combined with cold dark matter, this gives us the LCDM model, the standard picture of the cosmos for the past 25 years.
Source: Dark energy flips its sign, but the Hubble tension refuses to budge