In Minkowski space, which is the mathematical framework used in special relativity, the light cones represent the causal structure of spacetime. The light cones divide spacetime into three regions: the future light cone, the past light cone, and the elsewhere region. The light cones are symmetric, meaning that the future light cone and the past light cone have the same shape and size.
If, hypothetically, the future light cone were larger than the past light cone, it would have several implications that would challenge the fundamental principles of causality and the nature of time as we understand them based on our current understanding of physics. Here are some potential implications:
Retrocausality: A larger future light cone would imply that events in the future can influence events in the past. This would violate the principle of causality, which states that causes must precede their effects. It would allow for retrocausal influences, where future events could affect past events, leading to paradoxes and contradictions.
Time Travel: If the future light cone extends further in spacetime than the past light cone, it would open up the possibility of time travel to the past. An observer could potentially traverse the larger future light cone and encounter events that occurred in the past, leading to temporal paradoxes such as the grandfather paradox or the bootstrap paradox.
Breakdown of Determinism: A larger future light cone could challenge the concept of determinism, which assumes that the state of the universe at any given moment uniquely determines its future evolution. With a larger future light cone, the future would become less predictable and dependent on past conditions, introducing a non-deterministic element into the fabric of causality.
It's important to note that these implications are highly speculative and go beyond the current understanding of physics. The current framework of special relativity, with its symmetric light cones, forms the foundation of our understanding of causality, time, and the relationship between events in spacetime. Any departure from this framework would require significant modifications to our current understanding of fundamental physics.