On January 17, 2025, Carnegie Science and NASA commemorated the centennial of Edwin Hubble's groundbreaking discovery at the 245th meeting of the American Astronomical Society in Washington, D.C.
Hubble's identification of the Cepheid variable star V1 in 1923 at Mount Wilson Observatory revealed that the Milky Way is just one of billions of galaxies. This marked a pivotal moment in cosmology, leading to the understanding that the universe extends beyond our galaxy.
Using the Hooker Telescope, Hubble's findings contradicted the prevailing belief that the Milky Way encompassed the entire universe. His observations indicated that V1 was located in the Andromeda nebula, which was much farther away than previously thought.
The implications of Hubble's work were profound, prompting a shift in the scientific community's perspective on the cosmos. Harlow Shapley, a contemporary astronomer, famously lamented the impact of Hubble’s discovery, stating, 'Here is the letter that destroyed my universe.'
Hubble's legacy continued with the Hubble Space Telescope, which has expanded our knowledge of the universe, revealing distant galaxies and phenomena that Hubble could not have imagined. His analysis established that the farther a galaxy is, the faster it appears to be receding from Earth, leading to the formulation of Hubble's law.
The discovery of the expanding universe was further solidified by the work of Georges Lemaitre, who linked Hubble's observations to the concept of an expanding universe, eventually leading to the term 'big bang.'
Despite his contributions, Hubble remained skeptical about the runaway universe interpretation of redshift data. Modern astrophysics, however, has confirmed that the universe is indeed expanding, with the Hubble Constant now measured at 13.8 billion years for the age of the universe.
Recent discoveries using the Hubble Space Telescope have revealed that the universe's expansion is accelerating, a phenomenon attributed to 'dark energy.' This ongoing research continues to challenge our understanding of cosmic dynamics.
The upcoming NASA Roman Space Telescope aims to provide further insights into dark matter and dark energy, potentially refining measurements of the Hubble constant through cosmic surveys.
Hubble's initial discovery of a distant galaxy not only transformed our understanding of the universe but also reshaped humanity's perception of its place within it.