Science develops in lots of ways. There are purposeful discoveries, like the marsquakes, where researchers have a target, have some sort of expectation, and they get data of that target to see if their expectations are true or false or sideways. Other times, discoveries occur completely by accident. This is the case with the discovery of two radio bright galaxies that photobombed ALMA observations of a completely different pair of systems. 

Researchers led by Yoshinobu Fudamoto were surveying distant galaxies as they appeared when the universe was just a few percent of its current age. In two of the forty galaxies in the survey, stray light was spotted that was eventually matched to a pair of previously undiscovered galaxies that can’t be seen in shorter wavelengths of light. Dust is one of those things that is almost everywhere, and just like a lot of dust in the air will block blue shades of light and make everything appear red, dust in the galaxy can block all the short wavelengths of light and make things only appear to radio telescopes. 

In a new paper appearing in Nature, the team discusses the possibility that there is a significantly larger population of these massive distant galaxies than previously thought; those galaxies are just hidden by dust.

More Information

Waseda University press release

“Normal, dust-obscured galaxies in the epoch of reionization,” Y. Fudamoto et al., 2021 September 22, Nature