Traveling to Planet Rosebud: The Age Difference Mystery

Who is older when David arrives at planet Rosebud, David or Alexis?

Based on the data, when David arrives at planet Rosebud, Alexis is older by how much?

Answer:

When David arrives at planet Rosebud, Alexis is older by approximately 2.15 years.

David is 30 years old and his sister Alexis is 25 years old when David leaves to travel to planet Rosebud, which is 20 lightyears away. David travels at a speed of 0.85c, resulting in time dilation effects due to special relativity.

The Lorentz factor (γ) for David's journey is approximately 1.543, causing time to slow down for him. When David begins his journey, he is 5 years older than Alexis. During his travel, David experiences time dilation, and when he arrives at planet Rosebud, his age is around 46.3 years.

Meanwhile, Alexis remains on Earth aging at a normal rate. By the time David reaches planet Rosebud, the time it took for him to travel has caused Alexis to be older by approximately 2.15 years.

Due to the effects of time dilation, Alexis is older than David when he arrives at planet Rosebud. The exact age difference can't be determined without additional information such as the time dilation factor or journey time.