Born in Concord, Massachusetts, Wood attended The Roxbury Latin School with the initial intent of becoming a priest. But he decided to study optics instead when he witnessed a rare glowing aurora one night and believed the effect to be caused by "invisible rays". In his pursuit to find these "invisible rays", Wood studied and earned numerous degrees from Harvard, MIT and the University of Chicago. He taught briefly at the University of Wisconsin and eventually became a full-time professor of "optical physics" at Johns Hopkins University from 1901 until his death.

His wrote many articles on spectroscopy, phosphorescence and diffraction. But it's his work in ultra-violet light that his is most well known for.

Another claim to fame was his debunking of N-rays in 1904. Visiting the discovering laboratory at the behest of the journal Nature, he surreptitiously removed an essential prism from the apparatus. The effect did not vanish, showing that it had always been self-deception.

He discovered that the darkest area of the Moon in ultraviolet light is the Aristarchus Plateau. In 1909, Wood constructed the first practical liquid mirror astronomical telescope, by spinning mercury to form a paraboloidal shape, and investigated its benefits and limitations.

Wood has been described as the "father of both infrared and ultraviolet photography". Though the discovery of electromagnetic radiation beyond the visible spectrum and the development of photographic emulsions capable of recording them pre-date Wood, he was the first intentionally to produce photographs with both infrared and ultraviolet radiation. He developed a filter, Wood's glass, that was opaque to visible light but transparent to ultraviolet and is used in modern-day blacklites. He used it for ultraviolet photography but also suggested its use for secret communication. He was also the first person to photograph ultraviolet fluorescence. He also developed a lamp, Wood's lamp, that radiated only ultraviolet. The slightly surreal glowing appearance of foliage in infrared photographs is called the Wood effect.

Wood also authored non-technical works. In 1915, Wood co-authored a science fiction novel, The Man Who Rocked the Earth, with Arthur Train; a sequel, The Moon Maker, was published the next year. He also wrote and illustrated two books of children's verse, How to Tell the Birds from the Flowers (1907) and Animal Analogues (1908).

Wood died in Amityville, New York.

Works by Wood

About Wood

• [Anon.] (2001) "Wood, Robert Williams", Encyclopaedia Britannica, Deluxe CDROM edition