# Spaceship arriving at a planet

• norvegicusbas
In summary, the conversation discusses a paradox in Einstein's theory of relativity regarding a spaceship approaching a distant planet at the speed of light and the potential outcome if the spaceship was made from a massless material. It is determined that the light from the spaceship's headlights will always arrive before the spaceship, but if the spaceship was made from a massless material, it would not have its own inertial rest frame and the light would no longer have to move at the speed of light in the frame of the ship.
norvegicusbas
Hello.
Me and a friend of mine were trying to get our heads around a few of the paradoxes that are found within Einstein's theory of relativity and he came up with something we could not work out ( though I am sure someone here will be able to :)

Imagine you were in a spaceship traveling at the speed of light towards a distant planet. This planet is very dark and the spaceship needs to put on its headlights to see exactly where this planet is. Soon as the headlights are switched on all those aboard the spaceship ( according to their reference frame ) see the light from the headlights shine off into the blackness of space at the speed of light and strike the planet. With the planet well lit from the spaceships headlights the ship continues to approach for an eventual landing. But what will the people on the planets surface see? Do they see the light from the headlights arriving at a point in time before the arrival of the spaceship?

The light from the headlights of the spaceship will always arrive before the spaceship arrives. The spaceship can (at least hypothetically) approach the planet with a speed almost the speed of light but it can never reach the speed of light.

Passionflower said:
The light from the headlights of the spaceship will always arrive before the spaceship arrives. The spaceship can (at least hypothetically) approach the planet with a speed almost the speed of light but it can never reach the speed of light.

What would the outcome be though if the spaceship was made by some incredibly advanced alien race and could be constructed ( along with the passengers ) from a massless material?

norvegicusbas said:
What would the outcome be though if the spaceship was made by some incredibly advanced alien race and could be constructed ( along with the passengers ) from a massless material?
Well in that case it could never slow down and was doomed forever to travel at the speed of light. But clearly you must understand there is no such material.

norvegicusbas said:
What would the outcome be though if the spaceship was made by some incredibly advanced alien race and could be constructed ( along with the passengers ) from a massless material?
In that case the ship does not have its own inertial rest frame, so it is no longer true that the light from the headlights must move at c in the frame of the ship.

## 1. How does a spaceship arrive at a planet?

A spaceship typically arrives at a planet by using its propulsion systems to slow down and enter orbit around the planet. This may involve a series of maneuvers and calculations to ensure a safe and accurate landing.

## 2. How long does it take for a spaceship to arrive at a planet?

The time it takes for a spaceship to arrive at a planet varies depending on factors such as the distance between the two objects, the speed of the spaceship, and the type of propulsion system used. It can range from a few days to several months.

## 3. How do scientists communicate with a spaceship arriving at a planet?

Scientists can communicate with a spaceship using radio signals. The spaceship's communication systems are designed to receive and transmit these signals, allowing for communication between the crew on the spaceship and the scientists on Earth.

## 4. What safety measures are taken when a spaceship arrives at a planet?

Before a spaceship arrives at a planet, extensive safety measures are taken to ensure the safety of the crew and the success of the mission. This may include testing and double-checking all systems and procedures, as well as having contingency plans in place for potential emergencies.

## 5. What happens when a spaceship arrives at a planet?

When a spaceship arrives at a planet, the crew will typically begin their exploration and research of the planet. This may involve collecting samples, taking measurements, and conducting experiments to learn more about the planet's atmosphere, surface, and potential for sustaining life.

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