Peter John Young (31 July 1954—5 September 1981) was a British astrophysicist who made major contributions to extragalactic astronomy and cosmology.

Educated at Leeds Grammar School,[1] Young studied mathematics at St John's College, Cambridge (1972-1975), where he was Senior Wrangler (highest-placed First Class degree) in 1975.

[6] In 1980, Sargent, Young, Boksenberg, and Tytler[7] studied the Lyman-alpha forest in the rest-frame ultraviolet portion of quasar spectra, concluding that it arose from absorption by a cosmological distribution of partly ionized neutral Hydrogen.

[2][dubious – discuss] On 5 September 1981,[2] Young committed suicide by taking potassium cyanide which he had obtained from a chemistry stockroom at the university.

[10] According to Sargent and Peter Goldreich, Young had suffered from depression and psychological issues since his time at Cambridge and had previously talked about killing himself.