The university is responsible for many modern scientific advancements and is among a small group of institutes of technology in the United States that are devoted to the instruction of pure and applied sciences.

Scientists and engineers at or from the university have played an essential role in many modern scientific breakthroughs and innovations, including advances in space research, sustainability science, quantum physics, and seismology.

[20] Caltech started as a vocational school founded in present-day Old Pasadena on Fair Oaks Avenue and Chestnut Street on September 23, 1891, by local businessman and politician Amos G.

At a time when scientific research in the United States was still in its infancy, George Ellery Hale, a solar astronomer from the University of Chicago, founded the Mount Wilson Observatory in 1904.

The board of trustees offered to turn Throop over to the state, but the presidents of Stanford University and the University of California, Berkeley successfully lobbied to defeat the bill, which allowed Throop to develop as the only scientific research-oriented educational institute in southern California, public or private, until the onset of World War II necessitated the broader development of research-based science education.

[27] The promise of Throop attracted physical chemist Arthur Amos Noyes from MIT to develop the institution and assist in establishing it as a center for science and technology.

To that end, as Hale wrote in The New York Times: Throop College of Technology, in Pasadena California has recently afforded a striking illustration of one way in which the Research Council can secure co-operation and advance scientific investigation.

President Scherer, hearing of the formation of the council, immediately offered to take part in its work, and with this object, he secured within three days an additional research endowment of one hundred thousand dollars.

The new funds were designated for physics research, and ultimately led to the establishment of the Norman Bridge Laboratory, which attracted experimental physicist Robert Andrews Millikan from the University of Chicago in 1917.

[28] Under the leadership of Hale, Noyes, and Millikan (aided by the booming economy of Southern California), Caltech grew to national prominence in the 1920s and concentrated on the development of Roosevelt's "Hundredth Man".

On November 29, 1921, the trustees declared it to be the express policy of the institute to pursue scientific research of the greatest importance and at the same time "to continue to conduct thorough courses in engineering and pure science, basing the work of these courses on exceptionally strong instruction in the fundamental sciences of mathematics, physics, and chemistry; broadening and enriching the curriculum by a liberal amount of instruction in such subjects as English, history, and economics; and vitalizing all the work of the Institute by the infusion in generous measure of the spirit of research".

In 1928, a division of biology was established under the leadership of Thomas Hunt Morgan, the most distinguished biologist in the United States at the time, and discoverer of the role of genes and the chromosome in heredity.

Kármán later helped create the Jet Propulsion Laboratory, and played an integral part in establishing Caltech as one of the world's centers for rocket science.

By the end of the war, Caltech had essentially become an extension of the U.S. Navy’s Bureau of Ordnance, with its rocket research providing important technology to U.S. combat capabilities.

In response to the war in Korea and the pressure from the Soviet Union, the project was Caltech's way of assisting the federal government in its effort to increase national security.

The following week, Ross McCollum, president of the National Oil Company, wrote an open letter to Dabney House stating that in light of their actions he had decided not to donate one million dollars to Caltech.

[49] In 2010, Caltech, in partnership with Lawrence Berkeley National Laboratory and headed by Professor Nathan Lewis, established a DOE Energy Innovation Hub aimed at developing revolutionary methods to generate fuels directly from sunlight.

Goodhue conceived the overall layout of the campus and designed the physics building, Dabney Hall, and several other structures, in which he sought to be consistent with the local climate, the character of the school, and Hale's educational philosophy.

[61] Caltech is incorporated as a non-profit corporation and is governed by a privately appointed 46-member board of trustees who serve five-year terms of office and retire at the age of 72.

[63] Caltech dedicates significant resources to attract top-tier faculty and provides them with substantial financial support to foster their research and academic endeavors.

[74] Admission to Caltech's graduate study is highly competitive, with faculty evaluating factors such as academic preparation, research experience, scientific interests, and recommendations from teachers or mentors.

Caltech partnered with UCLA to establish a Joint Center for Translational Medicine (UCLA-Caltech JCTM), which conducts experimental research into clinical applications, including the diagnosis and treatment of diseases such as cancer.

The playing of that piece is not allowed at any other time (except if one happens to be listening to the entire 14 hours and 5 minutes of The Ring Cycle), and any offender is dragged into the showers to be drenched in cold water fully dressed.

[173] In recent years, the Student Affairs Office has also taken up pursuing investigations independently of the Board of Control and Conduct Review Committee, an implicit violation of both the honor code and written disciplinary policy that has contributed to further erosion of trust between some parts of the undergraduate community and the administration.

Other distinguished researchers have been affiliated with Caltech as postdoctoral scholars (for example, Barbara McClintock, James D. Watson, Sheldon Glashow and John Gurdon) or visiting professors (for example, Albert Einstein, Stephen Hawking and Edward Witten).

[181] Astronomer George O. Abell (BS 1951, MS 1952, PhD 1957) while a grad student at Caltech participated in the National Geographic Society-Palomar Sky Survey.

In 2013, President Obama announced the nomination of France Cordova (PhD 1979) as the director of the National Science Foundation and Ellen Williams (PhD 1982) as the director for ARPA-E.[196] Richard Feynman was among the most well-known physicists associated with Caltech, having published the Feynman Lectures on Physics, an undergraduate physics text, and popular science texts such as Six Easy Pieces for the general audience.

Long-time Caltech President Robert Andrews Millikan was the first to calculate the charge of the electron with his well-known oil-drop experiment, while Richard Chace Tolman is remembered for his contributions to cosmology and statistical mechanics.

2004 Nobel Prize in Physics winner H. David Politzer is a current professor at Caltech, as is astrophysicist and author Kip Thorne and eminent mathematician Barry Simon.

[203] Companies such as Quora, Contour Energy Systems, Impinj, Fulcrum Microsystems, Nanosys, Inc., Photon etc., Xencor, and Wavestream Wireless[204] have emerged from Caltech.