The universe is a vast, dark ocean. We see only the glowing foam on its surface — stars and galaxies. But hidden in the depths are two invisible forces: dark matter, which with its gravity keeps galaxies from flying apart, and dark energy, which, on the contrary, pushes space itself apart, making the universe expand faster and faster. They are usually considered independent, but what if there is a connection between them — an invisible exchange, like deep currents carrying energy from one force to another?
A new cosmological model proposed by astrophysicists describes just such a 'current.' Moreover, it is not constant but oscillates — changing direction like a giant cosmic pendulum. Energy flows from dark matter to dark energy and back in a certain rhythm. This rhythm is born from the physics itself: quantum fluctuations (tiny bursts of energy), stretched by the expansion of the universe to supergalactic scales, can influence the overall background: this is called the backreaction of super-Hubble inhomogeneities.
To test the idea, scientists compared it with three datasets: the cosmic microwave background map (CMB), baryon acoustic oscillation data (BAO — imprints of sound waves in the early universe), and Type Ia supernova observations (these 'standard candles' allow us to measure distances). It turns out that the oscillation amplitude could be quite noticeable — the data do not rule out such a scenario. However, the oscillating model did not provide a statistically significant advantage over the standard ΛCDM (lambda-CDM), where dark energy is simply a cosmological constant. In other words, the good old ocean with two stationary water masses still describes observations just as well.
But the very fact that a 'living' exchange between dark matter and dark energy is not rejected is already a result. It's like suspecting for the first time that deep currents exist and learning to measure their possible strength. Now, with newer, more precise telescopes, we can look not just for 'whether there is a current' but for its exact rhythm and direction, and then, perhaps, the dark ocean of the universe will become a little more transparent.
Oscillations in the energy exchange between dark components may be linked to quantum fluctuations that, during inflation (super-fast expansion), were stretched to sizes exceeding the visible universe and now 'push' on it from outside.
In Liu Cixin's novel 'The Dark Forest,' dark matter and dark energy remain a mysterious backdrop, but the idea of invisible interactions changing the fate of the universe is very much in the spirit of this work.