Some mysteries in science disappear with more precise measurements, filling in the gaps with a puff of new data. And sometimes, a second glance simply reinforces the fact that you have a puzzle on your hands.
It’s the latest in the case of a new study that challenges the fundamental laws of physics in the universe.
The Hubble constant is an expression of the expansion rate of the universe. Unfortunately, there is more than one solution to it, depending on how you measure it.
The expansion rate was calculated using the faint glow left behind by the first light ever found, known as the Cosmic microwave backgroundabout 68 kilometers per second / megaparsec. Looking at the way stars and galaxies are receding from us today, it’s a lot like 73 km/sec/million blocks.
Obviously, these two sets of measurements are not identical. Not even close. But if we get some small details wrong, such as the true distance of distant objects while calculating their flight to distance, there may be a chance that the two numbers will come close to overlapping.
In this latest study, researchers from the Swiss Federal Institute of Technology in Lausanne (EPFL) used data from the Gaia spacecraft to recalibrate the brightness of pulsars known as civics.
By correlating a known brightness with distance, and then looking for examples in the depths of space, we can accurately piece together a measure of the universe. This calibration is the first rung of a “cosmic ladder” used to calculate greater distances in space, and through which the universe becomes larger.
The good news is that improvements in accuracy are helping us better detect the Hubble Constant.
Then there is the not so good news. The most recent data confirms a Hubble constant or expansion rate of 73.0 ± 1.0 km/s/Mpc, which would make it nowhere near meeting the alternative measurement of 67.4 ± 0.5 km/sec/mpc.
This (Hubble tension) gap of 5.6 km/s/MPa is still a big problem – something is wrong somewhere, and we’re more certain of it now than ever.
“The more confirmation we get of the accuracy of our calculations, the more we conclude that the discrepancy means that our understanding of the universe is wrong, that the universe is not quite what we thought it would be,” He says EPFL astrophysicist Richard Anderson.
The researchers say the way the new readings were taken, through discovery of the new Cepheid clusters and observations from multiple angles, as well as cross-referencing with other clusters, can be used in many other calculations of light and distance in space.
In fact, it will be useful in determining the geometry of the Milky Way as a whole: how the elements of our galaxy are laid out and how this relates to other galaxies far from our planet.
“The high-resolution calibration we have developed will allow us to better determine the size and shape of the Milky Way as a galaxy with a flat disk and its distance from other galaxies, for example,” He says Astrophysicist Mauricio Cruz Reyes, of the EPFL.
“Our work also confirmed the reliability of the Gaia data by comparing it with that from other telescopes.”
Research published in Astronomy and astrophysics.
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