The Universe never ceases to amaze us. Recent observations suggest that dark energy, the enigmatic force believed to explain the accelerating expansion of the cosmos, might not behave as previously thought. This data, gathered through distant and ancient galaxies, calls our fundamental understanding into question.
Dark energy accounts for nearly 70% of the Universe, dwarfing ordinary matter, which makes up barely 5%. Yet its origin remains a mystery. It is invisible, elusive, and up until now, scientists considered it a cosmological constant, stable over time. However, recent findings challenge this hypothesis.
An international collaboration involving over 900 researchers has studied the movement of galaxies over billions of years. The data indicates that the force attributed to dark energy does not appear to be uniform. This unexpected behavior could suggest a gradual weakening or even the presence of another force at play.
The DESI (Dark Energy Spectroscopic Instrument) project plays a pivotal role in these discoveries. By creating a 3D map of the Universe spanning 11 billion years, this instrument, based in Arizona, reconstructs the evolution of galaxies. These analyses reveal patterns that do not align with a constant dark energy, calling decades of scientific consensus into question.
Some researchers propose alternative theories, such as an expansion governed solely by gravity, consistent with Einstein's predictions. If proven, dark energy as currently conceptualized could vanish from cosmological models.
However, these findings are preliminary. Caution is advised, emphasizes physicist Robert Caldwell, who is not involved in the study and describes the observations as "fascinating yet still uncertain." Astronomers are awaiting additional data before deciding whether a fundamental revision of cosmology is warranted.
Why is this question so critical? Because the fate of the Universe may depend on it. If dark energy intensifies, it could lead to a catastrophic expansion known as the "Big Rip." Conversely, if it weakens, the Universe might evolve toward a more stable state. But rest assured: these scenarios would unfold over billions of years.
Meanwhile, for us, the coming years will be decisive in gaining a clearer understanding of the cosmic future. One thing is certain: every answer raises new questions, inviting us to explore even further.
How does dark energy work?
Dark energy is a hypothesis to explain the accelerated expansion of the Universe. It acts as a repulsive force, counteracting the gravitational pull of galaxies. It is detected indirectly through observations of galaxies and supernovae. These measurements show an expansion that is faster than expected, incompatible with simple gravity alone.
Its origin remains a mystery. Some scientists believe it is a fundamental property of space-time, while others suggest it stems from unknown particles or fields. Understanding dark energy is crucial. Its nature and behavior directly influence the fate of the Universe, whether through a Big Rip or eternal expansion.