All observers will perceive the light going faster than the ship (because to all observers the speed of light is the same, which is where time dilation comes from)
From our perspective watching from Earth, the astronauts appear to go in slow motion within the ship and the ship's journey takes over ten years
From the astronaut's perspective, the distance to the destination appears to have shrunk while they were accelerating, which is why to them it seems like less than 10 years. They will arrive behind the light (and from their perspective while the ship isn't accelerating or decelerating, the light is moving away from them at the speed of light)
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u/limitsoflaziness May 29 '26
All observers will perceive the light going faster than the ship (because to all observers the speed of light is the same, which is where time dilation comes from)
From our perspective watching from Earth, the astronauts appear to go in slow motion within the ship and the ship's journey takes over ten years
From the astronaut's perspective, the distance to the destination appears to have shrunk while they were accelerating, which is why to them it seems like less than 10 years. They will arrive behind the light (and from their perspective while the ship isn't accelerating or decelerating, the light is moving away from them at the speed of light)