The discovery of a giant bubble 820 million light-years from Earth, led by the University of Hawaii, is considered a fossilized relic of the origin of the universe. Astronomer Brent Tully of the UH Institute of Astronomy and his team unexpectedly found a bubble in the galactic web. The entity was named Hoʻoleilana, a term taken from Kumulipo, a Hawaiian creation hymn that refers to the origin of structure.

New findings published Astrophysical Journal mention that these massive structures were predicted by the Big Bang theory to be the result of 3-dimensional fluctuations found in the material of the early universe known as Baryon Acoustic Oscillations (BAOs).

“We weren’t looking for it. It’s so large that it extends to the fringes of the sky sector we’re analyzing,” Tully explained. “This is a much stronger feature than expected due to increased galaxy density. Its enormous diameter of one billion light-years exceeds theoretical expectations. If its formation and evolution are consistent with theory, this BAO is closer than expected, indicating a high value for the expansion rate of the universe.”

Astronomers identified the bubble using data from Cosmicflows-4, the largest definitive collection of distances to galaxies to date. In the fall of 2022 Tully published a unique catalog. The research team believes this may be the first time astronomers have identified a separate structure associated with BAO. This discovery could help strengthen scientists’ knowledge of the consequences of galaxy evolution.

large bubbles of matter

According to the accepted Big Bang theory, the universe consisted of a cauldron of hot plasma, similar to the interior of the Sun, for the first 400,000 years. In the plasma, the electrons were separated from the atomic nuclei. During this period, the slightly denser regions began to collapse under the influence of gravity, although the intense radiation bath tried to push the matter away. This struggle between gravity and radiation caused the plasma to oscillate or fluctuate and radiate outward.

The greatest fluctuations in the early universe depended on the distance the sound wave could travel. This distance, measured by the speed of sound in plasma, was about 500 million light-years, and was recorded when the universe cooled and ceased to be plasma, leaving behind huge three-dimensional waves. Over the ages, galaxies formed in huge bubble-like structures at their density peaks. Correctly recognized patterns in the distribution of galaxies can reveal the characteristics of these ancient messengers.

“I am the group’s cartographer, and the three-dimensional mapping of Hoʻoleilana helps us understand its content and its relationship to its environment,” said researcher Daniel Pomarede of CEA Paris-Saclay University in France. “It’s been an incredible process to create this map and see how Hoʻoleilana’s giant crust is made of elements that were once thought to be one of the largest structures in the universe.”

The same research team also identified the Laniākea Supercluster in 2014. This structure, including the Milky Way, is relatively small. Laniakea stretches about 500 million light-years across to the near edge of this much larger bubble.

Disclosure of a single BAO

Tully’s team discovered that Hoʻoleilana was cited in a 2016 research paper as the most prominent among several shell-like structures detected in the Sloan Digital Sky Survey. However, previous studies had not revealed the entire structure, and this team was unable to conclude that they had found BAO.

Using the Cosmicflows-4 catalog, the researchers were able to see the entire spherical shell of galaxies, detect their center, and show a statistical increase in galaxy density in all directions from that center. Ho’oleilana encompasses many well-known structures previously discovered by astronomers, such as the Harvard/Smithsonian Great Wall containing the Hair Cluster, the Hercules Cluster, and the Sloan Great Wall. It is at the center of the Volopas Supercluster. The historic Volopas Gap, a vast, empty spherical region, is located in Hooleilana.

Hoʻoleilana’s results

Simulation tests have shown that the shell structure, defined as Hoʻoleilana, has less than a 1% chance of being a statistical coincidence. Ho’oleilana has features of a theoretically predicted baryonic acoustic oscillation, including a prominent location at the center of a rich supercluster; but it looks stronger than expected.

In detail, Ho’oleilana is slightly larger than would be expected from findings from the Standard Model of Cosmology theory and previous statistical pairing studies of galaxy separation. The size is consistent with observations of the local expansion rate of the Universe and galaxy flows at large scales, and also points to subtle problems with the Standard Model. Source