Hubble’s V1: The Star That Proved the Universe is Bigger Than We Imagined

A century ago, Edwin Hubble discovered a Cepheid variable star in the Andromeda Galaxy, a moment that forever altered humanity’s perception of the cosmos. This seemingly unremarkable star, named V1, proved that the universe extended far beyond the Milky Way, challenging the prevailing understanding of the cosmos.

Hubble’s Discovery of V1: A Milestone in Astronomy

Edwin Hubble’s discovery of the Cepheid star V1 in 1923 was a breakthrough moment in science. Using the 100-inch Hooker Telescope, the largest of its time, Hubble identified V1 as a pulsating star whose luminosity correlated with its distance. By measuring its light curve, he calculated that Andromeda was over 2.2 million light-years away, far beyond the boundaries of the Milky Way.

Hubble’s discovery of V1 paved the way for an even more groundbreaking revelation: the universe is expanding. By measuring the redshift of distant galaxies, Hubble established that the farther a galaxy is from Earth, the faster it is moving away. This phenomenon, now known as the Hubble-Lemaître Law, provided the first evidence of an expanding universe.

The implications of this discovery were profound. It introduced the concept of a finite beginning, leading to the development of the Big Bang theory. Belgian physicist Georges Lemaître used Hubble’s data to propose that the universe originated from a “primeval atom,” a notion that revolutionized our understanding of time and space.

The Role of Cepheid Variables: Cosmic Mileposts

Cepheid variables, like V1, play a crucial role in measuring cosmic distances. These stars pulsate at predictable rates, with their brightness directly linked to their intrinsic luminosity. This relationship allows astronomers to calculate distances to galaxies with remarkable accuracy.

Hubble’s use of Cepheid variables transformed them into essential tools for mapping the universe. Today, they form the first rung of the cosmic distance ladder, enabling astronomers to measure distances to faraway galaxies and refine our understanding of the universe’s scale.

The Hubble Space Telescope: Extending the Vision

Seventy years after Edwin Hubble’s groundbreaking work, his legacy was honored with the launch of the Hubble Space Telescope in 1990. Orbiting above Earth’s atmosphere, this marvel of engineering has pushed the boundaries of human knowledge, capturing breathtaking images of the universe and uncovering its secrets.

The Hubble Space Telescope has provided a wealth of discoveries, from the age of the universe (13.8 billion years) to the existence of dark energy. It has captured phenomena such as star-forming regions, colliding galaxies, and distant supernovae, offering unprecedented insights into the cosmos.

The Expanding Universe: New Challenges and Mysteries

Hubble’s discoveries were just the beginning. The realization that the universe is expanding led to the discovery of dark energy, a mysterious force driving the acceleration of cosmic expansion. Observations from the Hubble Space Telescope and other instruments revealed that the rate of expansion is not uniform, raising questions about the universe’s ultimate fate.

Today, astronomers are exploring the implications of dark energy and its role in shaping the cosmos. Upcoming missions, such as the Nancy Grace Roman Space Telescope, aim to study dark energy in greater detail, potentially unlocking new insights into the nature of the universe.

The Enduring Impact of Hubble’s Legacy

Edwin Hubble’s discovery of V1 was more than a scientific achievement; it was a paradigm shift that reshaped humanity’s understanding of its place in the universe. By proving that the Milky Way is just one of countless galaxies, Hubble expanded our perspective and inspired a sense of wonder about the cosmos.

This legacy continues to drive scientific exploration. The Hubble Space Telescope and its successors have built on his work, uncovering new mysteries and pushing the boundaries of knowledge. From the origins of galaxies to the search for habitable exoplanets, Hubble’s influence is felt in every corner of astronomy.

Lessons from V1: The Power of Curiosity

Hubble’s discovery of V1 underscores the importance of curiosity and the pursuit of knowledge. By questioning assumptions and seeking evidence, Hubble demonstrated the value of scientific inquiry in uncovering the truths of the universe. His work serves as a reminder that even the most unassuming discoveries can have profound implications, transforming our understanding of the world.

As we celebrate 100 years since Hubble’s groundbreaking discovery, we are reminded of the power of curiosity to drive progress and inspire future generations.

Conclusion: A Century of Cosmic Exploration

Edwin Hubble’s discovery of V1 marked the beginning of a new era in astronomy, revealing a universe far larger and more dynamic than previously imagined. His work laid the foundation for modern cosmology, inspiring generations of scientists to explore the cosmos and uncover its mysteries.

As we commemorate this centennial milestone, we are reminded of the profound impact of Hubble’s legacy. From the Cepheid variable star in Andromeda to the Hubble Space Telescope, his discoveries have transformed our understanding of the universe and our place within it.

Reference:

Simon Cornish et al, Long-lived entanglement of molecules in magic-wavelength optical tweezers, Nature (2025)