Do your past, present, and future all exist simultaneously? Are you watching this video, being born, and lying on your deathbed at this very moment? Surprisingly, the answer might be yes. But how can that be? What does it mean, and how does time work?
Imagine the universe as a child painting pictures on paper. Each picture captures everything happening in the universe at a single moment. With each new moment, various events occur everywhere—people are born and die, civilizations expand, and you might miss the bus. Our universe-child creates a new picture that replaces the old one, much like a movie where only the current moment is real. The past is gone, and the future is yet to come. This is how time feels, right?
But what if time is something else entirely? What if the universe-child has already completed all its drawings and stacked them on top of each other? This creates a block—a block of time containing the entire history of the universe. In this block, the past, present, and future are equally real and exist simultaneously.
This concept feels counterintuitive because we perceive only the present as real. How can the past and future be real right now? According to the theory of relativity, they kind of have to be. Relativity suggests that time and space are interconnected, forming a spacetime continuum. As you move through space, you also move through this block of time, meaning time passes differently for different people based on their movement through space relative to each other. Consequently, what you perceive as “now” is merely your version of now, with many different “nows” existing in the universe, all equally real.
Imagine three alien spaceships a million light-years away. The first spaceship hovers in space, sharing the same “now” with you. If you had a magical instantaneous internet connection, you could chat with the aliens in real-time. The second spaceship, moving away from us at 30 km/s, experiences a different “now,” allowing the aliens to converse with your ancestors in 1924. The third spaceship, flying towards you at the same speed, experiences yet another “now,” enabling communication with your descendants in 2124.
So, which “now” is correct? Relativity is based on cosmic democracy, meaning all observers’ perspectives in the universe are equally valid. Therefore, your past, present, and future must all exist simultaneously because, for different aliens, they all occur in their present.
This implies that the distinction between past, present, and future is an illusion. The universe isn’t a series of events evolving through time like a movie but a static block where all times coexist and are real. However, if the future is already written, how can we have free will? Quantum mechanics complicates this further.
Quantum processes are inherently unpredictable. For example, a radioactive atom could decay at any moment, and no oracle can predict it with certainty. Quantum particles can influence the world, leading to unpredictable outcomes. If quantum uncertainty exists, the future can’t be set in stone, suggesting that the future isn’t real in the same way as the past.
For every individual object, the past, present, and future are well-defined. Your death will always follow your birth, never before or simultaneously. So, for you, “now” makes sense.
Returning to the block universe, perhaps it doesn’t contain the future. Instead, the block represents the past, with a thin, uneven layer on the surface as the present. This surface comprises countless individual “nows,” each experienced by someone or something in the universe. As new events occur and uncertainties become certainties, the border moves upward, creating new time in the universe. This growing block universe allows for decision-making and shaping your future.
We began with time as a movie, moved to a frozen block universe, and ended with a growing block universe where time passes, and the future is open. But which is correct? What is real—the present, the past, or the future? The truth is, no one knows for sure. Some scientists believe “now” only makes sense near you, while others think time itself is an illusion. Time might even be an emergent property from a deeper level of reality.
The concept of time remains abstract and elusive, possibly beyond complete human comprehension. Fortunately, there’s a vast world of things we do understand about the universe that you can explore right now.
Imagine you are living in a block universe where the past, present, and future coexist. Create a time capsule with items that represent your current “now.” Write a letter to your future self, describing your thoughts on time and how you perceive it. Bury or hide the capsule to be opened at a future date, and reflect on how your understanding of time might change.
Use your creativity to design a poster that illustrates the concept of the spacetime continuum. Include elements that show how time and space are interconnected. Use drawings, symbols, and labels to explain how different observers might experience different “nows” based on their movement through space.
In groups, role-play a scenario involving three alien spaceships experiencing different “nows.” Each group member takes on the role of an alien from one of the spaceships. Discuss and debate which “now” is correct, and explore how relativity allows for multiple valid perspectives. Present your findings to the class.
Create a game that demonstrates the concept of quantum uncertainty. Use dice or cards to introduce unpredictability and chance. Discuss how these elements relate to the idea that the future isn’t set in stone and how this affects our understanding of free will and decision-making.
Write a short story where the protagonist travels through a growing block universe. Describe their experiences as they move through different “nows,” encountering past events and potential futures. Use the story to explore themes of time, free will, and the nature of reality.
Time – The ongoing sequence of events that occur in succession from the past through the present to the future. – In physics, time is a crucial factor when studying how fast an object moves.
Universe – All of space and everything in it, including stars, planets, and galaxies. – Scientists use telescopes to explore the universe and learn more about distant galaxies.
Past – The time before the present. – In history class, we learn about the past to understand how it shapes our world today.
Present – The current moment or period of time. – Right now, in the present, we are learning about the laws of motion in physics.
Future – The time that is yet to come. – Many scientists are curious about what the future holds for space travel and exploration.
Relativity – A theory in physics developed by Albert Einstein that explains how time and space are linked for objects that are moving at a constant speed in a straight line. – According to the theory of relativity, time can pass differently depending on how fast you are moving.
Block – A solid piece of material with flat surfaces, often used in physics to study motion and forces. – In our physics experiment, we used a wooden block to demonstrate friction on different surfaces.
Quantum – The smallest possible discrete unit of any physical property, often referring to energy levels in physics. – Quantum mechanics helps scientists understand the behavior of particles at the smallest scales.
Democracy – A system of government where the citizens exercise power by voting. – In our social studies class, we discussed how democracy allows people to have a say in their government.
Illusion – A false perception or belief, often used in philosophy to discuss how our senses can deceive us. – The magician’s trick was just an illusion, making us question what we thought we saw.
