Candles of distant galaxies dispel dark energy

White dwarf eyes of the artist

American astronomers in their new work , published in the journal Science, tell how they managed to bring the measurement accuracy of large space distances to 4%. The stars of a special type - type Ia supernova - helped them in this.

These supernovae are the result of a blast of white dwarfs. Those, in turn, are remnants of stars that have completed their life cycle when thermonuclear reactions cease in their depths. Due to the fact that such supernovae have the same maximum luminosity, they can be used as standard meters (or, as they are also called, standard candles) to measure the distance to their galaxies.

Patrick Kelly, lead author of research from the University of Berkeley, says: “For a couple of weeks, a Type Ia supernova becomes very bright before it begins to fade. It turns out that the decay rate of its glow depends on the absolute brightness of the explosion. " And if this brightness is known - then from the observed brightness it is possible to calculate the distance to the luminary, just as the candlestick brightness decreases as it moves away from the observer.
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Until now, one incomprehensible factor influenced the measurement accuracy - the distance to supernovae measured depended on the environment in which it was located. For example, the mass of a galaxy in which a star exploded could deflect the calculated distance by up to 5%.

Astronomers in their work identified a set of supernovae, the distance to which can be calculated with greater accuracy. These stars are found in galaxies rich in young stars. As Kelly explains, "Apparently, it was these dwarfs that exploded when they were relatively young, and their small age scatter could have contributed to this effect."

Improving the accuracy of measuring distances to galaxies will not only help to more clearly understand the picture of the past of our Universe. In 2011, three scientists received the Nobel Prize, proving with the help of these “candles” that the Universe is expanding with acceleration. Because of this, we had to introduce the concept of " dark energy " - an unknown force pushing the galaxy apart. This force is so great that according to the observations of the Planck Observatory from 2013, dark energy is more than two thirds of the total mass-energy of the Universe.

So far, scientists have not finally chosen a hypothesis that would explain the origin of this force. And just high-precision measurements of the rate of expansion of the Universe, which will show whether the speed varies with time, and how, can help in choosing one of the main hypotheses.