Through the eyes of the giants, the galaxies of the universe cling like foam to the surface of the eternal ocean, forming into clumps and threads around the inky voids.
This shimmering network took eons to come together, gradually solidifying under the gravitational guidance of what had been, billions of years ago, an evenly dispersed fog of white-hot particles that had just emerged from the Big Bang furnace.
Although this growth may seem slow to us mere mortals, physicists Nhat Minh Nguyen, Dragan Hutterer, and Yue Wen at the University of Michigan want to slow it even further, and fix one of science’s most vexing problems in the process.
Their proposed modification of the model that better describes our current universe could resolve a major discrepancy in observations of the expanding waistline in space.
You might complain that you can’t get something for nothing these days, that there’s more empty space out there today than there was yesterday. Something is causing nothingness to grow, making its way into the gaps between galaxies to gently push the large-scale structure of the universe apart at an ever-increasing rate.
Since we don’t know what’s behind this mysterious push, we refer to it as dark energy.
“If gravity acts as an amplifier that promotes perturbations of matter to grow into large-scale structure, then dark energy acts as a dampener that dampens these perturbations and slows the growth of structure.” He says Nguyen, lead author of the investigation into large-scale structure growth.
“By studying how cosmic structure assembles and grows, we can try to understand the nature of gravity and dark energy.”
The exact rate of expansion, known as the Hubble constant (H0), is not at all clear. Measure the way certain types of exploding stars recede into the distance, and you might get an acceleration of 74 kilometers per second per megaparsec. Using the “light echo” of the extended radiation still bouncing back after the Big Bang – the cosmic microwave background (CMB) – H0 is closer at about 67 kilometers per second.
This may not seem like a big difference, but the discrepancy has persisted through enough investigations that it can no longer be dismissed as a trivial error.
Nguyen, Hütterer and Winn took a fresh look at Flat ΛCDM The combinatorial cosmological model as a potential source of false assumptions. If cosmology were a chess game, this would be the board and the pieces laid out on the tiles of general relativity, moved by the push of dark energy, and aligned by the gravitational effects of dark matter.
By recreating the chess pieces we see today, we can effectively see how the game began, at a glance Rapid inflation To the time when the first stars collapse, to the formation of galaxies and their eventual emergence in giant interconnected filaments.
If for some reason this process deviates from what the consensus model predicts, hindering the growth of the universe’s large-scale structure, the tension between different scales of the universe’s accelerating expansion will disappear.
The researchers used a combination of measurements including ripples in the cosmic web, gravitational lensing events, and details in the cosmic microwave background to arrive at a statistically convincing conclusion that the cosmic web is growing more slowly than the ΛCDM cosmology model predicts.
“The difference in growth rates that we are likely to detect becomes more pronounced as we get closer to the present day.” He says Nguyen.
“Individually and collectively, these different investigations point to growth inhibition. Either we’re missing some systematic error in each of these investigations, or we’re missing some late-breaking new physics in our Standard Model.”
Although there are no clear contenders for what might halt the growth of the cosmic web, future measurements of the universe’s large-scale structure may at least indicate whether the idea needs to be explored further.
It took the universe 13.7 billion years to look this beautiful. We can wait a few more years to learn the secrets of these beautiful-looking cosmic wrinkles.
This research was published in Physical review letters.
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