Microwave spectrum of oxygen ions

Microwave spectrum of oxygen ions in MACS1149-JD1 detected with ALMA. It was originally infrared light with a wavelength of 88 micrometers, and ALMA detected it as microwaves with an increased wavelength of 893 micrometers due to the expansion of the Universe. Credit: Hashimoto et al. - ALMA (ESO/NAOJ/NRAO)