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A new study has found that the signal of dark energy change could be a systematic error.

Dark energy again forced the cosmologists to slow down with loud conclusions. Recent data have hinted that the force accelerating the expansion of the universe can change over time. A new test showed that part of the signal can be born not because of the changing dark energy, but because of a slight discrepancy between key cosmological data sets.
Samsuzzaman Aphrosis and Suvodip Mukerji of the Tata Institute of Basic Research in Mumbai published an analysis in the journal Physical Review D. Scientists have checked how stable data on supernova and barion acoustic oscillations, including DESI results. It was DESI that recently reported the signs that the equation of the state of dark energy can change with the redshift, that is, at different stages of cosmic history.
Dark energy helps explain the accelerated expansion of the universe. The main controversy around the nature of dark energy comes down to a simple question: whether dark energy acts as a cosmological constant, or the influence of dark energy has changed throughout the life of the universe. The answer is important not only for the theory, but also for predictions about the future of the cosmos.
To test, scientists use the equation of the state of dark energy. The parameter describes the ratio of the pressure and density of dark energy. You can measure the parameter through observations of distant objects and a redshift showing how quickly the objects are moving away from the observer.
Aphrosis and Mukherji proposed to compare two independent cosmological instruments through the duality ratio of cosmological distances. Within the framework of the general theory of relativity, two ways to measure the distances in the universe must be interconnected. If the connection is disturbed at least slightly, the conclusions about the properties of dark energy can shift.
The authors compared the data on supernovae and barionic acoustic oscillations. Supernovae help to estimate distances by the brightness of distant explosions of stars. Barionic acoustic oscillations show a trace of ancient density waves that propagated in hot plasma shortly after the Big Bang and left a large-scale structure in the distribution of matter.
The audit showed that both data sets generally agree with the fundamental distance ratio, but give a slight discrepancy. A small difference was associated with the shift of the parameters of the dark energy state equation from the values expected for the simple cosmological constant. In other words, even a weak discrepancy between the data can enhance the impression that dark energy is changing over time.
The authors emphasize that the result is maintained with different methods of parameterization and additional stability checks of analysis. Therefore, according to the researchers, it is too early to talk about the reliable detection of dynamic dark energy.
The method can be useful when working with future large sets of cosmological data. New sky reviews will give astronomers much more measurements, but the growth in the volume of information will increase the risk of hidden systematic errors. Checking the compatibility of different cosmological instruments will help to more accurately separate the real signal from the displacements to the data.

Dark energy again forced the cosmologists to slow down with loud conclusions. Recent data have hinted that the force accelerating the expansion of the universe can change over time. A new test showed that part of the signal can be born not because of the changing dark energy, but because of a slight discrepancy between key cosmological data sets.
Samsuzzaman Aphrosis and Suvodip Mukerji of the Tata Institute of Basic Research in Mumbai published an analysis in the journal Physical Review D. Scientists have checked how stable data on supernova and barion acoustic oscillations, including DESI results. It was DESI that recently reported the signs that the equation of the state of dark energy can change with the redshift, that is, at different stages of cosmic history.
Dark energy helps explain the accelerated expansion of the universe. The main controversy around the nature of dark energy comes down to a simple question: whether dark energy acts as a cosmological constant, or the influence of dark energy has changed throughout the life of the universe. The answer is important not only for the theory, but also for predictions about the future of the cosmos.
To test, scientists use the equation of the state of dark energy. The parameter describes the ratio of the pressure and density of dark energy. You can measure the parameter through observations of distant objects and a redshift showing how quickly the objects are moving away from the observer.
Aphrosis and Mukherji proposed to compare two independent cosmological instruments through the duality ratio of cosmological distances. Within the framework of the general theory of relativity, two ways to measure the distances in the universe must be interconnected. If the connection is disturbed at least slightly, the conclusions about the properties of dark energy can shift.
The authors compared the data on supernovae and barionic acoustic oscillations. Supernovae help to estimate distances by the brightness of distant explosions of stars. Barionic acoustic oscillations show a trace of ancient density waves that propagated in hot plasma shortly after the Big Bang and left a large-scale structure in the distribution of matter.
The audit showed that both data sets generally agree with the fundamental distance ratio, but give a slight discrepancy. A small difference was associated with the shift of the parameters of the dark energy state equation from the values expected for the simple cosmological constant. In other words, even a weak discrepancy between the data can enhance the impression that dark energy is changing over time.
The authors emphasize that the result is maintained with different methods of parameterization and additional stability checks of analysis. Therefore, according to the researchers, it is too early to talk about the reliable detection of dynamic dark energy.
The method can be useful when working with future large sets of cosmological data. New sky reviews will give astronomers much more measurements, but the growth in the volume of information will increase the risk of hidden systematic errors. Checking the compatibility of different cosmological instruments will help to more accurately separate the real signal from the displacements to the data.