In a case of celestial serendipity, an international team of researchers has discovered two hidden galaxies in empty space – the area devoid of almost anything at all – beaming out from behind huge clouds of space dust. One of them represents the most distant dust-obscured galaxies known to date.
The discovery suggests that our current census of our local universe is still incomplete.
“These new galaxies were missed not because they are extremely rare, but only because they are completely dust-obscured,” explains Yoshinobu Fudamoto from Waseda University and the National Astronomical Observatory of Japan.
The signals were discovered with the Atacama Large Millimeter/submillimeter Array (ALMA), when researchers were attempting to observe different targets.
Read more: The mysteries of ultradiffuse galaxies
Beyond their trickster shenanigans, the galaxies also reveal details about the early universe. Light takes a long time to travel to Earth, so the images snapped show what the galaxies looked like 13 billion years ago. Interestingly, they weren’t all that different to the typical galaxy in the same epoch – they were just playing hide-and-seek behind the cosmic cloud.
The researchers hope they can expand the galaxy census using the James Webb Space Telescope (JWST) along with the ALMA.
“Completing our census of early galaxies with the currently missing, dust-obscured galaxies, like the ones we found this time, will be one of the main objectives of JWST and ALMA surveys in the near future,” says co-author Pascal Oesch from University of Geneva, Switzerland.
The study was published in Nature and included researchers from Swinburne University of Technology and the ARC Centre of Excellence for All Sky Astrophysics in 3D.
Who knows what other galaxies we will find out there, if we have a big enough telescope?
Deborah Devis is a science journalist at Cosmos. She has a Bachelor of Liberal Arts and Science (Honours) in biology and philosophy from the University of Sydney, and a PhD in plant molecular genetics from the University of Adelaide.
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