Astronomers have to figure out almost everything about space using only the light that reaches us on Earth. This means we try to exploit every little property of light there is to try and piece together what's happening out there.
Light has a polarization, and there is linear polarization and circular polarization. It turns out that measuring the linear polarization of light lets you work out some interesting physics, in this case, about how stars are formed. For lots of reasons, the circular polarization of this light is ignored, because there wasn't any reason to expect any to be there, and it's quite difficult to measure accurately.
Recently, an argument was made that some linear polarization gets converted --and lost-- to circular polarization. We checked to see how commonly circular polarization could be found, and we found signals of it almost everywhere we looked. Even though we couldn't obtain accurate measurements of it, we found enough signatures in the data to be convinced that the circular polarization is real, and is a common occurrence.
This means that if we want to continue studying star formation in this way it will become necessary to improve our instruments so that all polarization is measured accurately.