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Cosmic Expansion: The solution is postponed until later

Cosmic Expansion: The solution is postponed until later

Behind the calculations of the universe’s expansion speed is a puzzle: a difference in numbers, depending on what we measure. the Latest notes Thanks to the James Webb Space Telescope, it has become possible to improve the calculations, but the discrepancy remains.

Called the “Hubble potential,” it is the difference between the observed cosmic expansion and what it should be — a measurement called the Hubble constant (named after 1920s astronomer Edwin Hubble). big size, Expansion is faster Than the models allow for with what we know about the Big Bang. In simple terms, this means that something fundamental is missing from the equations, and observations from the new telescope do not indicate that we are getting closer to a solution. Many theoretical physics texts I finish In recent years there has been it will not be Simple solution.

For cosmology, this is nothing less than an important debate: one concerning the composition of the universe, of which only 5% is made of ordinary matter, compared to 27% of “dark matter” and 68% of dark energy. If we do not know what these last two consist of, at least we can conclude that it is him The gravitational force of dark matter It is what gives galaxies their structure, which is the pressure they exert Dark energy (a type of repulsive gravitational force) that determines the acceleration of the universe. It is assumed that this repulsive force gradually took over the evolution of the universe, explaining the fact that the expansion is accelerating.

But if this model helps explain why expansion is accelerating, which is a discovery in itself, Only 25 years old– You are not allowed to go any further: what is this speed, and will the acceleration continue indefinitely. The fact that we don’t know what dark energy is doesn’t help us understand it either, and the fact that some physicists are talking about how dark energy could represent “new physics” means that consensus may take a long time.

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Since that moment, a quarter of a century ago, the existence of acceleration has been proven, and astronomers have tried to make various measurements, both in our cosmic “outskirts” – the nearest galaxies – and in our cosmic “outskirts”. As far as it was possible to observe. big size, New notes By James Webb Confirm the ones whereby the “real” acceleration is 8% faster Of “theoretical” acceleration.

There are still supporters of the theory that this is all a problem because of the limits of our observations: in other words, this difference is a “mirage.” They have fewer arguments as the observations in question become more precise, but they have no reason to give up, at least until we prove whether there is indeed “new physics” hidden in dark energy.

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