In 2016, the Center for Planetary Science proposed a hypothesis arguing a comet and/or its hydrogen cloud were a strong candidate for the source of the Wow! Signal. From 27 November 2016 to 24 February 2017, the Center for Planetary Science conducted 200 observations in the radio spectrum to validate the hypothesis. The investigation discovered that comet 266/P Christensen emitted a radio signal at 1420.25 MHz. The results of this investigation, therefore, conclude that cometary spectra are detectable at 1420 MHz and, more importantly, that the 1977 Wow! Signal was a natural phenomenon from a Solar System body.
@article{arxiv.1706.03259,
title = {Hydrogen Line Observations of Cometary Spectra at 1420 Mhz},
author = {Antonio Paris},
journal= {arXiv preprint arXiv:1706.03259},
year = {2017}
}