Philip Hauge Abelson (April 27, 1913 – August 1, 2004) was an American physicist, scientific editor and science writer.

After he collaborated with the Nobel Prize laureate Luis Alvarez they isolated the material, and became the co-discoverer of neptunium on 8 June 1940 with Edwin McMillan.

Abelson was a key contributor to the Manhattan Project during World War II, while working with the Naval Research Laboratory.

[1] Although he was not formally associated with the atom bomb project, the liquid thermal diffusion isotope separation technique that he invented at the Philadelphia Navy Yard was used in the S-50 plant in Oak Ridge, Tennessee, and proved a critical step in creating the large amount of nuclear fuel required for building atomic bombs.

After the war, he turned his attention under the guidance of Ross Gunn to applying nuclear power to naval propulsion.

While not written at an engineering-design level, he wrote the first physics report detailing how a nuclear reactor could be installed in a submarine, providing both propulsion and electrical power.

[8] Abelson may have been the original source of the phrase 'extraordinary claims require extraordinary evidence', which he used in 1978 and was subsequently popularised by Carl Sagan.

However, this contrasts what is said in a US National Research Council, Energy and Environment report on which his name appears along with Thomas F. Malone over a decade earlier in 1977: What is important is not that there are differences [in the models] but that the span of agreement embraces a fourfold to eightfold increase in atmospheric carbon dioxide in the latter part of the twenty-second century.

This would exceed by far the temperature fluctuations of the past several thousand years and would very likely, along the way, have a highly significant impact on global precipitation.Abelson died on August 1, 2004, from respiratory complications following a brief illness.

He was married to Neva Abelson, a distinguished research physician who co-discovered Rh factor testing (with L. K. Diamond).