Radar measurement
Radar (radio detection and ranging) can be used to measure the distance of objects within our solar system e.g. other planets
A radar pulse is transmitted, the signal reflects of the object then the reflection is received on Earth.
The time delay between sending and receiving the signal is measured. The distance of the object is then calculated using c = d / t where c = 3 x 108 m/s and d is the distance to and from the object.
Q. It takes 30 minutes for a signal to get to and return from Mars.
Calculate the distance between Earth and Mars a) in metres b) in light seconds
Why will the received signal be very weak?
Why is radar unsuitable for objects outside our solar system?
We can calculate the speed of an object relative to the Earth by sending out a series of pulses and measuring the time it takes for each pulse.
Q. Radar pulses are sent to an asteroid. It is found that the time it takes for the pulses to travel to and from the asteroid is decreasing. What does this mean?