Part 3/10:
Here’s where the paradox begins: The traveling twin's onboard instruments would record time passing more slowly due to their high velocity, while from Earth, it would seem the twin’s aging process has effectively slowed down during the trip. If the journey takes 23 years for the Earth twin, the spacefaring twin might only experience about 11.5 years passing—meaning they would return younger than their sibling.
The Core of the Confusion: Who Is Actually Older?
This setup leads to a perplexing question: Upon reunion, which twin is older?
- The initial intuition suggests that the stationary twin on Earth should be older because they experienced more elapsed time.