Dark energy may be losing energy: explaining strange behavior ⚡ экспресс
New data from the DESI survey point to an evolving dark energy that appears to have crossed the phantom divide in the recent past. This work presents a dissipative scenario where quintessence (a scalar field for dark energy) undergoes weak dissipation, naturally accounting for both evolution and phantom divide crossing without introducing pathological phantom-like dynamics. It's shown that even minimal dissipation can reproduce current DESI observational data, offering a physically motivated alternative to exotic dark energy models.
In the late 1990s, astronomers including Saul Perlmutter discovered that the universe is expanding at an accelerating rate. The cause was dubbed dark energy — an invisible force stretching the cosmos. For a long time, it was thought to be constant, but fresh data from the DESI telescope, which studies millions of galaxies via their light, showed: around 6 billion years ago dark energy changed its behavior, crossing a critical threshold beyond which its influence becomes even stranger. Physicists described this field like a pendulum. In a standard model, a pendulum meets no resistance and swings forever. But if you put it in a very thick fluid, it starts losing energy due to friction. Similarly, dark energy experiences an ultra-weak ‘friction’ that dissipates its energy and makes the expansion of the universe accelerate differently. No exotic hypotheses — just a natural energy loss. Previously, such a transition would have doomed the universe to a ‘Big Rip’ — a catastrophic end, but the subtle friction cancels this scenario.
🎯 The density of dark energy is so tiny that within the volume of Earth, it would amount to just a couple of kilograms — yet on cosmic scales, it determines the fate of the universe.