Scientists Find Dozens of ‘Invisible’ Galaxies, Changing Our Understanding of the Universe
Using the combined power of multiple astronomical observatories across the world, astronomers have discovered a stunning set of 39 massive galaxies that had previously been invisible.
The multiple discovery is the first of its kind, according to a study published on Wednesday in Nature, and is set to forever change the way in which scientists look at how galaxies are formed.
The galaxies, which are located billions of light-years away, are intimately connected with supermassive black holes and the distribution of dark matter.
In a press release, lead researcher Tao Wang at the University of Tokyo said:
“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. These were previously invisible to us … This finding contravenes current models for that period of cosmic evolution and will help to add some details, which have been missing until now.”
And while the Hubble Space Telescope has allowed astronomers to gain major insights into previously unknown parts of the universe, the research team from the University of Tokyo relied on the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile to uncover this latest massive find.
And it appears that the huge galaxies would overwhelm our humble view of the heavens if they were actually visible to us humans. Given the age and distance of the huge galaxies, they have always been hidden from our view thanks to the weak and stretched light emanating from them. As a result of such distance, the visible light becomes infrared.
Kotaro Kohno, the study’s author and a professor at the University of Tokyo, explained:
“The light from these galaxies is very faint with long wavelengths invisible to our eyes and undetectable by Hubble.
So we turned to the Atacama Large Millimeter/submillimeter Array (ALMA), which is ideal for viewing these kinds of things. I have a long history with that facility and so knew it would deliver good results.”
The infrared light from the distant galaxies was originally revealed by the NASA Spitzer Space Telescope before ALMA’s “sharp eyes” detected them, cutting through the thick dust that obscured them from our sight, Wang explained.
“It took further data from the imaginatively named Very Large Telescope in Chile to really prove we were seeing ancient massive galaxies where none had been seen before.”
The new discovery will also shed light on the existence of supermassive black holes. Professor Kohno explained:
“The more massive a galaxy, the more massive the supermassive black hole at its heart. So the study of these galaxies and their evolution will tell us more about the evolution of supermassive black holes, too.
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. Theoretical researchers will need to update their theories now.”
So what would the sky look like if we happened to live in one of these ancient, massive galaxies? Wang explained:
“For one thing, the night sky would appear far more majestic. The greater density of stars means there would be many more stars close by appearing larger and brighter … But 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.”
Wang is sure that in the future, new space-based telescopic technology will be able to reveal the chemicals, number of stars and basic composition of the dozens of galaxies that have been revealed. He explained:
“Previous studies have found extremely active star-forming galaxies in the early Universe, but their population is quite limited.
Star formation in the dark galaxies we identified is less intense, but they are 100 times more abundant than the extreme starbursts. It is important to study such a major component of the history of the Universe to comprehend galaxy formation.”