If you are inside a spaceship with no windows and moving at a constant velocity, it can be challenging to directly prove your own motion without any external reference points. However, there are a few indirect ways to infer or demonstrate your movement:
Internal Sensations: You can observe the sensations within your body, such as feeling pressed against the seat or experiencing a change in balance, which can indicate acceleration or movement. However, in the case of constant velocity, these sensations may not be as pronounced.
Instrumentation: The spaceship may be equipped with instruments that can provide objective measurements of movement. For example, an accelerometer can detect changes in acceleration or velocity. However, if the spaceship is truly in a state of constant velocity with no external forces acting upon it, these instruments would likely show no significant changes.
Communication: If you have a means of communication with individuals or entities outside the spaceship, they can provide confirmation of your motion. They may have access to external reference points, such as observing your departure or tracking your spacecraft's position using radar or other methods.
Outside Information: If you have access to information about your destination or surroundings, you may be able to infer your motion based on changes in distance or position relative to known landmarks or celestial bodies. This assumes that you have reliable and up-to-date information.
Experiments: Conducting experiments within the spaceship may reveal the effects of motion. For example, dropping an object and observing its trajectory or conducting experiments with pendulums or other moving objects can provide evidence of motion, such as Coriolis forces.
It's important to note that without external references or observations, proving your motion with absolute certainty may be difficult. However, employing a combination of the above methods can help you gather evidence and make reasonable inferences about your movement within the spaceship.