How long wil it take a radio wave to go from Earth to Mars? Whats the calculation for this?

Answer 1

That depends on where Mars is relative to the Earth. Keep in mind that planets don't have fixed locations; they are constantly in motion.

The Earth orbits the Sun at 1 AU. Mars at 1.5 AU. So at it's closest approach, Mars is 0.5 AU distant and at its furthest 2.5 AU distant.

1 AU is about 150 million km. Light travels 300,000 km/s. So it takes light 500 seconds to travel 1 AU.

Sending a radio signal to Mars would take as little as 250 s (just over 4 min) or as long as 1,250 s (almost 21 min.)

Double these times for round-trip signal. Trying to have a conversation with someone on Mars would be difficult. After asking a question, you'd have to wait between 8 min and 42 min for a response.

Answer 2

Radio travels at the same speed as light.
So to get the "radio distance" to any planet, you calculate the distance at the time (Earth and the planets are all orbiting the sun at different speeds, so the distance to any planet changes throughout the year).
Once you have the distance, you convert it to light-years (or light-minutes if you're talking about a planet in our solar system).
A light minute is equal to 17,987,547,480 metres or about 18 million kilometers.

Answer 3

calculation? try this

time between emission and reception = speed of light -2 over distance