Edwin Powell Hubble

Discover the life and legacy of Edwin Powell Hubble (1889–1953), the American astronomer whose observations revealed that the universe is expanding, reshaping cosmology forever.

Introduction

Edwin Powell Hubble is one of the towering figures in 20th-century astronomy. Born November 20, 1889, and passing September 28, 1953, he substantially altered humanity’s understanding of the cosmos. Through his observations and analysis, he demonstrated that what were once thought to be nebulous “spiral nebulae” beyond the Milky Way are in fact other galaxies, and that these galaxies are receding from us—with speeds proportional to their distances. This relationship is now famously known as Hubble’s law. His name is commemorated in the Hubble Space Telescope, a machine that continues extending our cosmic vision.

Hubble’s work anchored observational cosmology: from shifting the scale of the universe outward to providing empirical support to what became the Big Bang paradigm.

Early Life and Education

Edwin Hubble was born in Marshfield, Missouri, to Virginia Lee Hubble (née James) and John Powell Hubble, an insurance salesman with a law degree. Chicago.

As a youth, Hubble excelled not only academically but also athletically—he competed in track and field, basketball, and other sports. University of Chicago, majoring in mathematics, astronomy, and philosophy.

He then won a Rhodes Scholarship to study at Oxford University, where he studied law and the humanities, partly honoring a promise to his father.

He returned to the U.S. and completed his PhD in astronomy at the University of Chicago (Yerkes Observatory) in 1921, writing Photographic Investigations of Faint Nebulae.

During World War I, Hubble volunteered for the U.S. Army, serving in the 86th Division.

Career & Major Discoveries

Mount Wilson and Extragalactic Astronomy

After completing his PhD, Hubble joined the Mount Wilson Observatory in Pasadena, California, under the auspices of the Carnegie Institution.

One of his landmark achievements came in 1923–1924, when he used Cepheid variable stars (leveraging the period-luminosity relation earlier discovered by Henrietta Swan Leavitt) in the Andromeda “nebula” (M31) to establish that it was far farther than the Milky Way and thus a separate galaxy.

Then in 1929, Hubble published what is now known as Hubble’s law: the observation that more distant galaxies tend to recede from us at speeds roughly proportional to their distances (i.e. redshift ∝ distance). This provided the first clear empirical evidence that the universe is expanding.

Beyond that, he developed the Hubble sequence (galaxy morphological classification: spiral, elliptical, irregular) and investigated galaxy luminosities and distributions (e.g., Hubble luminosity law, Hubble–Reynolds law).

During World War II, Hubble served in a civilian posture at the Aberdeen Proving Ground, working in ballistics research and developing instrumentation (e.g. a high-speed clock camera) for trajectory studies. Legion of Merit.

He later also used the newly completed Hale 200-inch telescope at Palomar Observatory near San Diego, expanding the reach of observational cosmology.

Later Years & Death

Hubble married Grace Lillian Burke in 1924.

He suffered a heart attack in 1949, affecting his health thereafter.

Edwin Hubble died on September 28, 1953, in San Marino, California, from cerebral thrombosis (a brain clot).

His papers, observational logbooks, correspondence, and other materials are archived at the Huntington Library, San Marino, California.

Legacy & Impact

• The Hubble Space Telescope, launched in 1990, was named in his honor. It has since revolutionized deep-sky observation and our view of the universe.

• His discoveries firmly situated extragalactic astronomy and observational cosmology as major scientific fields.

• The concept of an expanding universe shaped modern cosmological theory, pushing forward the development of the Big Bang model and later research into dark energy and cosmic evolution.

• Classification of galaxy morphologies (spiral, elliptical, irregular) remains foundational in astronomy.

• Many honors and institutions bear his name: asteroid 2069 Hubble, the Hubble crater on the Moon, the Edwin P. Hubble Planetarium, schools, highways in Marshfield, and more.

• Because astronomy was not covered by the Nobel Prize during his life, Hubble lobbied for inclusion of astronomy in physics award criteria. That change occurred after his death.

Personality & Reflections

Hubble viewed astronomy almost as a calling. He once wrote:

“Astronomy is something like the ministry. No one should go into it without a call. I got that unmistakable call, and I know that even if I were second-rate or third-rate, it was astronomy that mattered.”

He also acknowledged the limitations of knowledge and the evolving nature of scientific horizons:

“The history of astronomy is a history of receding horizons.” “Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.” “Observations always involve theory.” “Equipped with his five senses, man explores the universe around him and calls the adventure Science.”

These lines reflect humility, the interplay of theory and evidence, and the sense of wonder that drove his work.

Lessons from Hubble’s Life

• Empirical daring reshapes assumptions. Hubble’s observational results challenged prevailing worldviews (e.g. Milky Way as sole galaxy).

• Theory and observation must go hand in hand. His work exemplifies how data and conceptual frameworks inform each other.

• Humility before frontier limits. His quotes suggest that science advances by acknowledging what we don’t yet know.

• Persistence across disciplines. Though he trained in law and the humanities, he followed his passion for astronomy, blending breadth with depth.

• Legacy outlives one’s lifetime. The telescope named after him continues to expand human knowledge, linking past to future.

Conclusion

Edwin Powell Hubble’s career marked a turning point in how humanity understands its place in the cosmos. By demonstrating that our universe is far larger and more dynamic than previously imagined, he opened doors to modern cosmology, reshaping both science and philosophical outlook. His legacy continues through instruments, ideas, and the ever-receding horizons that beckon us onward.