Final answer:
In special relativity, time dilation occurs when an object is moving relative to an observer at a significant fraction of the speed of light. To determine how fast the rocket must travel relative to the earth for time in the rocket to slow down to half its rate as measured by earth-based observers, we can use the time dilation equation and solve for the velocity.
Step-by-step explanation:
In special relativity, time dilation occurs when an object is moving relative to an observer at a significant fraction of the speed of light. According to time dilation, the rate of time in the moving object slows down compared to the rate of time observed by earth-based observers. To determine how fast the rocket must travel relative to the earth for time in the rocket to slow down to half its rate as measured by earth-based observers, we can use the time dilation equation:
t' = t / sqrt(1 - v^2/c^2)
where t' is the time observed by earth-based observers, t is the time experienced in the rocket, v is the velocity of the rocket relative to the earth, and c is the speed of light.
Let's assume that t' is half of t. Plugging in these values into the equation, we get:
t/2 = t / sqrt(1 - v^2/c^2)
We can solve this equation for v:
v = c * sqrt(1 - 1/4) = c * sqrt(3/4) = c * sqrt(3) / 2
Therefore, the rocket must travel at a speed of c * sqrt(3) / 2 relative to the earth for time in the rocket to slow down to half its rate as measured by earth-based observers.