Einstein’s theory of relativity describes how time passes differently for objects moving at high speeds and near the surface of massive things. This phenomenon, known as time dilation, has been a core principle of physics for over a century. However, an intriguing thought experiment reveals gaps in our understanding of time dilation that warrant a closer look.
The Experiment: Two Clocks, One Orbit
Imagine two identical atomic clocks that are perfectly synchronized on Earth’s surface. One clock remains on the ground while the other is loaded onto a spacecraft and launched into a circular geosynchronous orbit 36,000 km above Earth.
The orbiting clock completes one full revolution every 24 hours, always remaining in the same inertial reference frame as the ground clock. After 6.5 million years in this orbit, the spacecraft returns to Earth, and the clocks are compared again.
Time Dilation Defied
According to relativity, the orbiting clock should tick more ticks per orbit than the Earth clock due to the combined effects of General and Special Relativity. But the symmetrical nature of the orbit means any time dilation effects should cancel out over 24 hours. Yet relativity still predicts a discrepancy of one day after 6.5 million years.
Remarkably, both clocks tick off the same number of days over the multi-million year journey. This shows no actual time dilation occurs between the two reference frames. Still, the orbiting clock gains a day and loses sync with Earth due to some unexplained effect.
Rethinking Time Dilation
The symmetry of the orbit cancels out cumulative time dilation between the clocks. However, a discrepancy is still observed, disproving time dilation as the explanation. Some other phenomenon must cause the desynchronization.
This finding discounts time dilation as a complete model of reality. The mathematical predictions hold, but the physical ontology of time passing differently is dismissed through the thought experiment.
The Space Density Explanation
A compelling alternative is that higher space density at altitude affects clocks by requiring more ticks per orbit. If space contains a variable density gradient around massive objects like planets, this could account for the desynchronization without time dilation.
The observed evidence fits better with the hypothesis of a space density gradient influencing orbiting clocks. This provides a physical explanation for desynchronization without requiring time itself to pass differently in different inertial frames.
Einstein’s reputable theories cannot be discounted, but gaps exist between the mathematical models and the ontological explanations for observed phenomena. The case of the orbiting clocks casts doubt on time dilation as the causal factor behind clock desynchronization.
By questioning long-held assumptions in relativity through thought experiments like this one, we edge closer to a complete understanding of time and other deep mysteries of physics. The search continues for mechanisms that align with observation to fill the remaining gaps in current theories.