nebulium

(nəbˈjuːlɪəm)

(Elements & Compounds) a hypothetical element, now discredited

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References in periodicals archive ?

(Prior to this, many astronomers had believed that with powerful enough instruments all nebulae could be resolved into stars.) Huggins could not identify the bright spectral emission lines that give the nebula its blue-green color, so they were attributed to a hypothetical new element named nebulium.