Dark matter map hints at cracks in our understanding of the universe

Darkish matter map hints at cracks in our understanding of the universe


The Very Massive Telescope within the Chilean Atacama desert

ESO/F. Kamphues

The distribution of darkish matter within the universe could also be 10 per cent smoother than thought, doubtlessly upending our understanding of the evolution of the cosmos.

Right this moment, scientists introduced outcomes from the seven-year Kilo-Diploma Survey (KiDS), utilizing the Very Massive Telescope (VLT) on the European Southern Observatory in Chile to look at greater than 30 million galaxies within the universe as much as 10 billion mild years from Earth. These outcomes reaffirm earlier indications concerning the unfold of darkish matter.

“The universe appears to be less clumpy than our best theory of the universe at the moment would suggest,” says Catherine Heymans on the College of Edinburgh, UK, the examine’s lead creator. “It [would] mean there’s more to understand out there.”


Following the large bang 13.7 billion years in the past, our universe went by a interval of inflation and growth, forsaking remnant warmth within the course of that we are able to observe right this moment – the cosmic microwave background (CMB) – which reveals us the unfold of matter all through the universe.

Nonetheless, a wide range of darkish matter research over the previous few years have begun to indicate a discrepancy between the CMB and the measured distribution of darkish matter, which makes up about 85 per cent of the mass of the universe. The KiDS outcomes discover additional proof for that discrepancy.


Map displaying the unfold of darkish matter

The survey examined the sunshine bent, or lensed, by the gravitational pull of darkish matter in about 5 per cent of the universe as seen from Earth. This was mixed with observations of the clustering of galaxies from a separate survey, referred to as the Baryon Oscillation Spectroscopic Survey (BOSS), to supply an correct measurement of the unfold of darkish matter.

Whereas different surveys have additionally carried out related analysis, this newest examine was noticeable for its stage of accuracy, says Alan Heavens at Imperial Faculty London. “They are the most precise [results] that have been published so far,” he says.

If the findings are appropriate, they may have some broad implications. It might imply that gravity on massive scales is completely different than thought, with the speed at which matter falls into dense areas of the universe, as predicted by Einstein’s principle of normal relativity, slower than predicted. Or it may very well be that our understanding of darkish vitality, considered the motive force behind the accelerated growth of the universe, is much from full.

“This kind of discrepancy was not expected from our physical model of the universe,” says Elisabeth Krause on the College of Arizona. “The jury’s still out whether there is an explanation in the follow-up systematic effects we have to model, or if this is actual new fundamental physics.”

Additional surveys are beneath means, such because the worldwide Darkish Power Survey, to supply extra knowledge on these outcomes. And never everyone seems to be satisfied concerning the findings simply but. “It’s one of those tantalising results that is not enough on its own to say we need to overthrow everything,” says Heavens.

But when outcomes from different surveys counsel an analogous smoothness to darkish matter, it may very well be the beginning of some attention-grabbing new physics. “It’s another crack in the model,” says Heymans. “It’s still on that edge of starting to feel uncomfortable.”

Journal reference: Astronomy & Astrophysics, in press

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