"The clouds don't emit light or energy, but the neutral atomic hydrogen that they are made of gives off a distinct radio signal that astronomers were able to pick up using the National Science Foundation's Green Bank Telescope which measures radio waves."Apparently, these clouds do not emit light or energy, but they do emit radio waves that we can detect with out telescopes. Aghhh!!
I know that you already know this, but radio waves are one form of electromagnetic radiation, and (in terms of quantum mechanics) are packets of energy called photons. The energy of a photon is given by
Light has a wavelength of around 550nm, and so each photon carries some energy. Radio waves, however, have wavelengths from millimetres to many hundreds of kilometres. Such long wavelengths mean each photon carries a much smaller amount of energy, but they still carry energy!