PhysLink.com Logo
Science Fair Supplies Sale
Science Fair Supplies Sale

Question

How long does it take for a radio signal to go from Earth to Mars?
Asked by: Richard Boulais

Answer

Radio signals are electromagnetic waves, such as light or X-ray. The speed of electromagnetic waves in vacuum, is 300000km/sec (approximately).

In order to calculate the time of travel with this speed from Earth to Mars, we need to know the distance.

When the Mars and the Earth are at the opposite sides of the Sun, the distance is the largest: approximately: 378 million km. The time needed for an electromagnetic wave to cover this distance is approximately: 21 minute.

The closest distance between Mars and Earth is 78 million km, the time in this case is: 4.3 min.

So the time of travel between Earth and Mars is between 4.3 minutes and 21 minutes, depending on the actual distance between the two planets.
Answered by: Ferenc Szekely, Ph.D., Physicist, ELTE, Budapest, Hungary


Get $10 OFF glasses at EyeBuyDirect.com

Science Quote

'In a way science is a key to the gates of heaven, and the same key opens the gates of hell, and we do not have any instructions as to which is which gate. Shall we throw away the key and never have a way to enter the gates of heaven? Or shall we struggle with the problem of which is the best way to use the key?'

Richard Phillips Feynman
(1918-1988)


All rights reserved. © Copyright '1995-'2017 PhysLink.com