More precise understanding of dark energy achieved using AI

A UCL-led analysis staff has used synthetic intelligence (AI) methods to deduce the affect and properties of darkish power extra exactly from a map of darkish and visual matter within the universe protecting the final 7 billion years.

The study, submitted to the Month-to-month Notices of the Royal Astronomical Society and out there on the arXiv preprint server, was carried out by the Darkish Power Survey collaboration. The researchers doubled the precision at which key traits of the universe, together with the general density of darkish power, might be inferred from the map.

This elevated precision permits researchers to rule out fashions of the universe that may beforehand have been conceivable.

Darkish power is the mysterious pressure that’s accelerating the universe’s enlargement and is assumed to make up about 70% of the content material of the universe (with dark matter, invisible stuff whose gravity pulls galaxies, making up 25%, and regular matter simply 5%).

Lead creator Dr. Niall Jeffrey (UCL Physics & Astronomy) mentioned, “Utilizing AI to study from computer-simulated universes, we elevated the precision of our estimates of key properties of the universe by an element of two.

“To attain this enchancment with out these novel methods, we would wish 4 instances the quantity of information. This could be equal to mapping one other 300 million galaxies.”

Co-author Dr. Lorne Whiteway (UCL Physics & Astronomy) mentioned, “Our findings are in keeping with the present greatest prediction of dark energy as a ‘cosmological fixed’ whose worth doesn’t differ in space or time. Nonetheless, in addition they permit flexibility for a distinct rationalization to be appropriate. For example, it nonetheless might be that our concept of gravity is fallacious.”

Consistent with earlier analyses of the Darkish Power Survey map, first revealed in 2021, the findings recommend that matter within the universe is extra easily unfold out—much less lumpy—than Einstein’s concept of normal relativity would predict. Nonetheless, the discrepancy was much less vital for this examine in comparison with the sooner evaluation, because the error bars had been bigger.

The Darkish Power Survey map was obtained via a technique referred to as weak gravitational lensing—that’s, seeing how gentle from distant galaxies has been bent by the gravity of intervening matter on its method to Earth.

The collaboration analyzed distortions within the shapes of 100 million galaxies to deduce the distribution of all matter, each darkish and visual, within the foreground of these galaxies. The ensuing map coated 1 / 4 of the sky within the Southern Hemisphere.

For the brand new examine, researchers used UK government-funded supercomputers to run simulations of various universes primarily based on the information from the Darkish Power Survey matter map. Every simulation had a distinct mathematical mannequin of the universe underpinning it.

The researchers created matter maps from every of those simulations. A machine studying mannequin was used to extract the knowledge in these maps that was related to cosmological fashions. A second machine studying software, studying from the various examples of simulated universes with completely different cosmological fashions, checked out the actual noticed information and gave the chances on any cosmological mannequin being the true mannequin of our universe.

This new method allowed researchers to make use of far more data from the maps than can be potential with the earlier methodology. The simulations had been run on DiRAC Excessive Efficiency Computing (HPC) facility.

The following phase of darkish universe projects—together with the European Area Company mission Euclid, launched final summer—will significantly improve the amount of information we have now on the large-scale constructions of the universe, serving to researchers decide if the surprising smoothness of the universe is an indication present cosmological fashions are fallacious or if there’s one other rationalization for it.

At the moment, this smoothness is at odds with what can be predicted primarily based on evaluation of the cosmic microwave background (CMB)—the sunshine left over from the Massive Bang.

The Darkish Power Survey collaboration, of which UCL is a founding member, is hosted by the US Division of Power’s Fermi Nationwide Accelerator Laboratory (Fermilab) and entails greater than 400 scientists from 25 establishments in seven nations.

The collaboration has catalogued tons of of hundreds of thousands of galaxies, utilizing images of the night time sky taken by the 570-megapixel Darkish Power Digital camera, one of many world’s strongest digital cameras, over six years (from 2013 to 2019). The digital camera, whose optical corrector was constructed at UCL, is mounted on a telescope on the Nationwide Science Basis’s Cerro Tololo Inter-American Observatory in Chile.