“Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities… space and time not only affect but are also affected by everything that happens in the universe.”
- January 8, 1942 – March 14, 2018
- British
- Theoretical physicist, science writer
- Announced the black hole singularity theorem and Hawking radiation, and contributed to the popularization of science with his book “Talking about the Universe”
Quote
“Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities… space and time not only affect but are also affected by everything that happens in the universe.”
Explanation
This quote addresses a revolutionary shift in our understanding of the nature of space and time, which occurred with the publication of Albert Einstein’s theory of general relativity in 1915. Before Einstein’s work, space and time were seen as separate and absolute entities—a fixed, unchanging stage in which objects moved and events unfolded, as described by Newtonian physics. In this model, time passed uniformly for all observers, and space remained unaffected by the matter and energy within it. This view was consistent with everyday experiences, but it failed to explain phenomena observed in certain extreme conditions, such as the behavior of light near massive objects or the motion of planets under strong gravitational forces.
Einstein’s theory of general relativity fundamentally changed this perception. Space and time were now seen as interwoven into a four-dimensional fabric, known as spacetime, which could bend and stretch in response to the presence of mass and energy. This concept is often summarized by the famous saying: “matter tells space how to curve, and space tells matter how to move.” Essentially, the presence of mass (like a planet or star) warps the fabric of spacetime, and this curvature is what we perceive as gravity. In this dynamic framework, space and time are not passive backdrops, but active participants in the unfolding of events across the universe.
Hawking’s quote highlights the dramatic departure from classical physics to modern cosmology. Space and time are no longer static and separate; they are fluid and interactive. This understanding has profound implications, from the behavior of black holes to the expansion of the universe. The realization that the universe itself is shaped by the very matter and energy it contains has led to new insights into phenomena like the Big Bang and the curvature of space in extreme environments. In contemporary science, the idea that space and time are affected by the universe’s contents is foundational to theories like string theory, quantum gravity, and even our understanding of the cosmic microwave background radiation.
