Buzz
Both physics, psychology, and philosophy have endeavored to explain and analyze time - a familiar yet highly elusive concept.
Each of us has wished at some point to 'freeze' time in moments of joy or to avoid facing anticipated sorrows and farewells. The suspension of time remains a common detail in science fiction books and movies.
But can we genuinely make time stand still? To answer this extremely vague question, scientists must delve into the farthest corners of physics, philosophy, and human cognition.
What is time?
First and foremost, we must ascertain what the concept of time truly entails. Sean Carroll, a theoretical physicist specializing in time at the California Institute of Technology, explained to Live Science: “For a physicist, this question isn't overly difficult. Time essentially serves as a 'label,' a tool for measurement. It informs us when something occurs.”
Carroll elaborated: “Many physics equations fail to distinguish between past, present, and future. One domain where time manifests is in Albert Einstein's theory of relativity. According to Einstein's theory, time is measured by clocks. As the components of a clock must traverse through space, time becomes 'entangled' with space into a larger concept known as spacetime, serving as the foundation for the universe”.
The renowned theory of relativity has elucidated that time can be 'quantified' in a complex and challenging manner due to its dependence on the velocity of an observer relative to another. If you were to send an individual with a clock on a spacecraft at near-light speed, time for them would appear to pass slower compared to someone stationary on Earth. An astronaut plummeting into a massive gravitational black hole may perceive time differently than an observer at a distance.
However, that's not truly how time halts. While two clocks may not agree on the theory of relativity, each will still record the passage of time within its own frame of reference. If you were near a black hole, you wouldn't perceive any discernible difference. Yet, glancing at your wristwatch, it would progress at a rate of one second per second.
When time stops, all motion also comes to a halt
For Carroll, attempting to engineer a cessation of time holds no meaningful significance. We understand that a car is in motion because at various times, it occupies different positions in space. Physicists argue: “Motion entails change over time, thus time itself cannot move. In other words, if time were to cease, all motion would also cease”.
This is why in science fiction films, when superheroes momentarily pause time, everything and everyone around them also must remain motionless. Yet, in practical terms, this detail poses another question: “If space also had to stop, then air would also need to be still. So how would humans breathe then?”
But that's not all. When time stops, humans also wouldn't be able to see anything because light rays wouldn't reach our retinas anymore.
Stepping outside the realm of physics, time isn't just something read on a clock. It's also a sensation we have in our minds and bodies. It's a natural rhythm of the world. Time can sometimes feel very fast, and other times it can feel like it's crawling.
Craig Callender suggests that everyone's subjective impression of time will lead the question “Can time be stopped?” in a completely different direction.
There's a famous psychological illusion called 'chronostasis.' You can perform an experiment to experience the sensation chronostasis creates. Place a clock at the edge of your field of vision, then stare at something else for a moment. When you glance back at the clock and focus on the second hand, you'll see it frozen, as if time has momentarily stopped.
This illusion is related to the movement of the eyes called saccades. When your retinas flick rapidly back and forth to continuously take in images of the surrounding environment, to prevent you from seeing a blurry, chaotic mess, your brain automatically adjusts what it sees in real time and creates an impression of a continuous field of view.
“If we're just talking about our subjective feeling of time, then we can 'freeze' it for a moment by creating the chronostasis illusion for ourselves. That's the closest thing humans can do right now,” said Callender.
