We are getting closer to understanding dark energy

The work uses the most direct probe we have in the history of the expansion of the universe: Type Ia supernovae. These supernovae are a type of stellar explosion and act as a cosmic barometer, allowing us to measure surprisingly large distances in the universe. These distances can then be compared with our expectations. This is the same technology that was used to detect the presence of dark energy 25 years ago.

The difference now is in the size and quality of the supernova sample. Using new techniques, the DES team has 20 times more data, over a wider range of distances. This allows one of the most accurate measurements of w, giving a value of -0.8

At first glance, this is not the exact value of minus one that we expected. This may indicate that this is not the cosmological constant. However, the uncertainty in this measurement is large enough to allow a minus-one probability of 5%, i.e. a betting probability of only 20 to 1. This level of uncertainty is still not good enough to say anything, but it's an excellent start.

The discovery of the Higgs Boson subatomic particle at the Large Hadron Collider in 2012 required a probability of being wrong by a million to one. However, this measurement can refer to… The end of the “Big Rip” models., which has equations of state more negative than one. In these models, the universe expands indefinitely at an increasingly rapid pace, eventually decoupling galaxies, planetary systems, and even spacetime itself. This is comfortable.

As always, scientists want more data, and these plans are already underway. The DES results indicate that our new techniques will work in future supernova experiments with… European Space Agency's Euclid mission (launched July 2023) and the new Vera Rubin Observatory in Chile. It is expected that this observatory will soon use its telescope to obtain a first picture of the sky after construction, which gives an idea of ​​its capabilities.

These next-generation telescopes could find thousands more supernovae, helping us make new measurements of the equation of state and shedding more light on the nature of dark energy.