Theoretical Physicist Brian Greene Explains Time in 5 Levels of Difficulty | WIRED

Recent questions

• How does Earth's motion around the Sun relate to the passage of time?

  Earth's motion around the Sun is intricately connected to the passage of time. As the Earth orbits the Sun, it completes a full revolution approximately every 365 days, marking a year. This cyclical movement of the Earth creates the concept of time measurement based on days, months, and years. The correlation between Earth's motion and time showcases the fundamental relationship between space and time, highlighting how our understanding and experience of time are influenced by the physical movements of celestial bodies.

• What is the significance of the speed of light in relation to travel?

  The speed of light, which travels at an astonishing 671 million miles per hour, serves as a crucial limit to how fast things can travel in the Universe. According to the laws of physics, nothing with mass can exceed the speed of light. This limitation has profound implications for space travel and communication, as it sets a boundary for the maximum velocity achievable by any object or information. The speed of light not only shapes our understanding of the cosmos but also impacts technological advancements and scientific exploration in the realm of physics.

• How does Einstein's theory of relativity explain time dilation?

  Einstein's theory of relativity provides insights into the phenomenon of time dilation, which occurs with motion. According to this theory, as an object moves faster through space, time passes more slowly for that object relative to a stationary observer. This concept challenges our intuitive understanding of time as a constant and universal measure, revealing that time is a dynamic and relative dimension influenced by motion and gravity. Einstein's groundbreaking theory of relativity revolutionized our perception of time and space, paving the way for new discoveries and advancements in physics.

• What role does entropy play in the concept of time?

  Entropy, a fundamental concept in thermodynamics, plays a significant role in the understanding of time. The second law of thermodynamics states that entropy, or disorder, tends to increase over time in a closed system. This principle explains why events in the Universe progress from order to disorder, reflecting the irreversible nature of time's arrow. The concept of entropy provides a framework for comprehending the passage of time and the tendency for systems to evolve towards greater randomness and chaos. By studying entropy, scientists gain valuable insights into the fundamental laws governing the flow of time and the evolution of the Universe.

• How do Einstein's theories of relativity impact phenomena like GPS satellites?

  Einstein's theories of special and general relativity have a profound impact on phenomena like GPS satellites. These theories reveal that time is influenced by both speed and gravity, leading to effects such as time dilation. In the case of GPS satellites, which orbit the Earth at high speeds, the principles of relativity come into play. Without accounting for the time dilation effects predicted by Einstein's theories, GPS systems would experience significant errors in location calculations. By incorporating the insights of relativity into the design and operation of GPS satellites, scientists and engineers can ensure accurate and reliable navigation services for various applications.