How do rovers talk with Earth?I've been obsessed with astronomy for last few weeks. And a question crossed my mind. How do space rovers communicate with Earth? It is a pretty silly question because everyone knows that radio signals are used in extraterrestrial communication. Because radio waves travel a long distance.
But think about it. Light from the Sun reaches earth after eight minutes of it leaving the Sun's surface. Which means we see past the every time we look at the Sun. This time lag becomes ridiculous at huge distances. Mars is approximately 55 million kilometres from earth. While Sun is 150 Million kilometres away from the earth. Radio waves sent by Mars rovers are essentially electromagnetic radiation, ie...; light. Because of its proximity to earth, the light from Mars reaches earth approximately after 3 minutes. Once again, the information that a rover gives is history.
3 minutes is a pretty huge deal in terms of universe where splendid moments occur in split second. We can miss out rainbows, tornadoes, meteor hits etc..; Now ofcourse the rover keeps sending continuous information. Which means the information we perceive is long done. It's history.
Dinosaurs were extinct 66 million years ago. An alien on a planet 66 million light years away would see dinosaurs if it pointed its telepscope towards earth today (a gigantic telescope).
Things don't make sense at all in astronomical scale!!! This time lag due to speed of light is eminent and future is always the past.