Final answer:
The speed of the capsule relative to the ship is 0.198c, which is approximately equal to 0.200c.
Step-by-step explanation:
The velocity of an object relative to another object can be found by using the relativistic addition of velocities formula.
In this case, the spaceship is approaching the Earth at 0.100c and the message capsule is sent toward it at 0.100c relative to the Earth.
The relativistic addition of velocities formula is given by:
v = (v1 + v2) / (1 + (v1 * v2) / c^2)
Substituting the given values, we have:
v = (0.100c + 0.100c) / (1 + (0.100c * 0.100c) / c^2)
Simplifying the equation, we get:
v = 0.200c / (1 + 0.01) = 0.200c / 1.01 = 0.198c
Therefore, the speed of the capsule relative to the ship is 0.198c, which is approximately equal to 0.200c.