Since , the Universe is expanding: we say that it is expanding. But, on top of that, this expansion is accelerating! A phenomenon discovered in 1998 by international teams of scientists while studying the evolution of this expansion from star explosions. By looking at the light emitted by other more distant ones, called supernovae, the teams observed an acceleration of this expansion. To interpret this result, it was then concluded that a mysterious form of energy was the cause: black energy, also called dark energy.
Untraceable for the moment, she has been hunted down for decades. Some models even assume that it would not exist, and that it would be the who should be seen again! A new study published in also looked at dark energy, but this time on another aspect: the exact evaluation of the proportion it occupies in the universe. Their analysis, called Pantheon+, corresponds to the improvement of pre-existing methods but with, this time, more data and a better methodology, therefore less uncertainties with a result “17 times more restrictive than the previous evaluations in 1998”, explains to Futura Dillon Brout, first author of the study, and researcher at Harvard & Smithsonian Center for Astrophysics.
Only one third of matter in the universe
For this, the researchers used type Ia supernovae, called thermonuclear supernovae. They correspond to the explosion of already dead stars — white dwarfs — which are in a binary system. When a low mass star, less than 10 solar masses, exhausts its fuel, it contracts and changes into . If it is in a binary system, therefore with another star, it gradually sucks in the…
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