Hoyle, F.Narlikar, J. V.Wickramasinghe, N. C.2012-03-252012-03-251984-03-22http://hdl.handle.net/11007/1600It has become clear from sources observed by IRAS that there are many examples which attain maximum emission per unit (frequency) bandwidth longward of 100 μm. Here, we show that a large emissivity at such long wavelengths can be obtained by needle-shaped particles of free carbon. Indeed for needles with a sufficiently high ratio of length to diameter the large emissivity extends from the infrared through the whole microwave region of the spectrum.enRadiationMicrowavesArticle