Astronomers Discover Oldest Known Galaxies in the Cosmos

Ancient galaxies from the study are visible to ALMA (right) but not to Hubble (left). (Image (c) 2019 Wang et al.)

(CN) – Astronomers have discovered 39 massive and ancient galaxies that defy current models of the known universe and contain clues about the interactions of black holes with dark matter, a study published Wednesday revealed.

Using a chain of light-sensitive observatories located in the deserts of Chile, astronomers from the University of Tokyo were able to view “fundamental pieces of the cosmic puzzle,” according to the study, published in the scientific journal Nature.

The astronomers suspected there was more of the universe to see than the Hubble Space Telescope was able to reveal. Using the combined power of multiple observatories around the world, they found a “treasure trove” of previously unseen galaxies, which emit faint light with long wavelengths that are invisible to the human eye and undetectable by Hubble.

Researcher Tao Wang said in a statement that they turned to the Atacama Large Millimeter/submillimeter Array (ALMA) telescope system in northern Chile to view the light from these newly discovered galaxies.

“This is the first time that such a large population of massive galaxies was confirmed during the first 2 billion years of the 13.7-billion-year life of the universe,” Wang said. “This finding contravenes current models for that period of cosmic evolution and will help to add some details, which have been missing until now.”

Wang said that the theory of ancient, invisible galaxies was only substantiated after collecting data from the Very Large Telescope in Chile.

“Our initial suspicions about their existence came from the Spitzer Space Telescope’s infrared data,” said Wang. “But ALMA has sharp eyes and revealed details at submillimeter wavelengths, the best wavelength to peer through dust present in the early universe.”

University of Tokyo professor Kotaro Kohno said in the statement that the galaxies were invisible due to space dust obstructing views and because of the galaxies’ faint light.

Over time, the light from these massive ancient galaxies was stretched across huge distances of an ever-expanding universe, researchers said in the study, adding that visible light is stretched to the point where it becomes infrared.

Researchers calculate the distance and origin of galaxies based on how long their light has been stretched.

Kohno said the discovery of the ancient galaxies will help astronomers understand the evolution of super massive black holes.

“The more massive a galaxy, the more massive the supermassive black hole at its heart,” Kohno said. “Massive galaxies are also intimately connected with the distribution of invisible dark matter. This plays a role in shaping the structure and distribution of galaxies.”

Living inside one of the newly discovered galaxies, the night sky would look much different than the Milky Way pattern residents of Earth see.

“For one thing, the night sky would appear far more majestic,” Wang said. “The greater density of stars means there would be many more stars close by appearing larger and brighter.”

He added: “Conversely, the large amount of dust means farther-away stars would be far less visible, so the background to these bright close stars might be a vast dark void.”

Researchers said new observatories, such as the planned space-based James Webb Space Telescope, will allow them to study the chemical makeup of the galaxies and the stars within them.

“I’m eager for upcoming observatories like the space-based James Webb Space Telescope to show us what these primordial beasts are really made of,” Wang said.

%d bloggers like this: