Mysterious infrared light from space resolved perfectly

A research team using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the faintest millimeter-wave source ever observed. By accumulating millimeter-waves from faint objects like this throughout the Universe, the team finally determined that such objects are 100% responsible for the enigmatic infrared background light filling the Universe. By comparing these to optical and infrared images, the team found that 60% of them are faint galaxies, whereas the rest have no corresponding objects in optical/infrared wavelengths and their nature is still unknown.