Leonard Searle was an English-born American astronomer who worked on theories of the Big Bang

Big Bang

The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...

. He was born in Mitcham

Mitcham

Mitcham is a district in the south west area of London, in the London Borough of Merton. A suburban area, Mitcham is located on the border of Inner London and Outer London. It is both residentially and financially developed, well served by Transport for London, and home to Mitcham Town Centre,...

, a suburb of London, and studied at St Andrews

University of St Andrews

The University of St Andrews, informally referred to as "St Andrews", is the oldest university in Scotland and the third oldest in the English-speaking world after Oxford and Cambridge. The university is situated in the town of St Andrews, Fife, on the east coast of Scotland. It was founded between...

 in Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 and Princeton

Princeton University

Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....

 in New Jersey

New Jersey

New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

. After receiving his doctorate he started working at the University of Toronto

University of Toronto

The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...

 in 1953, leaving in 1960 for the California Institute of Technology

California Institute of Technology

The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

. In 1963 he moved to Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 for a post at the Mount Stromlo Observatory

Mount Stromlo Observatory

Mount Stromlo Observatory located just outside of Canberra, Australia, is part of the Research School of Astronomy and Astrophysics at the Australian National University .-History:...

, before settling finally at the Carnegie

Carnegie Institution for Science

The Carnegie Institution for Science is an organization in the United States established to support scientific research....

 observatories in Pasadena

Pasadena, California

Pasadena is a city in Los Angeles County, California, United States. Although famous for hosting the annual Rose Bowl football game and Tournament of Roses Parade, Pasadena is the home to many scientific and cultural institutions, including the California Institute of Technology , the Jet...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, in 1968. In 1989 he became director of the Carnegie Observatories.

Searle's work focused on the conditions of the Big Bang and the early universe, and on the formation of heavy elements in stars. One of his main fields of study was the abundance of helium

Helium

Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

 in the early universe. With Wallace Sargent

Wallace L. W. Sargent

Wallace Leslie William Sargent is an American astronomer. He is often known as Wal Sargent. Although now a U.S. citizen, he was born in Elsham, England. He received his Ph.D...

 he developed a model to calculate the hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

-to-helium composition of galaxies

Galaxy

A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...

. As director of the Carnegie Observatories, he was also central to the construction of the Las Campanas Observatory

Las Campanas Observatory

Las Campanas Observatory is an astronomical observatory owned and operated by the Carnegie Institution for Science It was established in 1969 and remains the primary observing site of that institution. The headquarters is located in La Serena, Chile and the observatory is in the southern Atacama...

 in Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, considered the best natural imaging telescopes in the world. Searle married Eleanor Millard, whom he met at Princeton, in 1952. Eleanor Searle, a medieval

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

historian, died in 1999.