• Question: If we were on a different planet, would radiowaves travel and work the same way?

    Asked by to Mark, Matthew, Mike, Paul, Sabina on 13 Mar 2014. This question was also asked by .
    • Photo: Mike Lee

      Mike Lee answered on 13 Mar 2014:


      Radio waves are actually just the same as light rays so would work on another planet. There might be a probably with sending radio waves around the planet if it has a thin atmosphere. On earth, we can send radio waves around the planet by bouncing them off a layer of the atmosphere called the ionosphere. If the other planet did not have an ionosphere then you would not be able to send the waves around the curve of the planet. Just like light, radio waves prefer to travel in straight lines.

    • Photo: Paul Coxon

      Paul Coxon answered on 13 Mar 2014:


      Radio is a form of electromagnetic (EM) radiation, just like light, x-rays, and the rest of the EM spectrum. The only real difference is the wavelength – radio waves are very long. Radio waves used for broadcasting televison and radio are several metres in length. Some natural radio waves detected in space have wavelengths over 100 km! All forms of electromagnetic radiation travel very well in the vacuum of space. In fact radio waves are used to send commands and receive data from probes NASA has sent into outer space.

      Last year the Voyager 1 probe left our solar system – it’s the greatest distance any manmade object has ever travelled and it’s still sending very very faint radio signals back to Earth.

      Radio communications on another planet would require an atmosphere similar to Earth. The Earth has a thin layer of ionised gas near the topmost zone of the atmosphere which reflects the waves back to a receiver. This is how we can send waves around the Earth across large distances.

    • Photo: Mark Jackson

      Mark Jackson answered on 16 Mar 2014:


      As others have pointed out, the atmosphere would be different and so radio waves would propagate a bit differently. It is also important that the GPS system would also work differently due to slight gravitational differences on the other planet. While the Earth is almost spherical, it has small bulges that slightly change the gravitational field. The fact that satellites move fast, and are so high in orbit, also produce slight changes. These effects would be impossible to account for in Newton’s Theory of Gravity, but Einstein’s General Theory of Relativity predicts specific corrections for such effects. It’s a good thing, too – if we didn’t understand General Relativity, the GPS system would quickly give the wrong answer and become worthless!

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