GregJones Posted May 4 Share Posted May 4 If we reflected lasers back to earth from mars could we receive information before the information is sent? If the information travelled at the speed of light to mars and back to earth would it effectively be time travel for information? Link to comment Share on other sites More sharing options...
Mordred Posted May 4 Share Posted May 4 3 minutes ago, GregJones said: If we reflected lasers back to earth from mars could we receive information before the information is sent? If the information travelled at the speed of light to mars and back to earth would it effectively be time travel for information? That would be a causality violation c is the speed limit of information exchange as well. Link to comment Share on other sites More sharing options...
zapatos Posted May 4 Share Posted May 4 What is it in your scenario is it that makes you believe information might be 'time traveling'? Is it because you use lasers? Or because of the speed of light? Because it is 'round trip' travel? Because there is something about Mars that is special? Link to comment Share on other sites More sharing options...
iNow Posted May 4 Share Posted May 4 18 minutes ago, GregJones said: If we reflected lasers back to earth from mars could we receive information before the information is sent? No Link to comment Share on other sites More sharing options...
GregJones Posted May 4 Author Share Posted May 4 Thanks for the great replies I actually just asked the same question on LBC radio and the presenter read it out and amazingly someone replied via the radio station having calculated how long it would take the laser to return to earth. I actually thought that if we sent binary light frequencies to a reflector deep in space via laser that the information could be received before the information was sent. Link to comment Share on other sites More sharing options...
pzkpfw Posted May 4 Share Posted May 4 (edited) Radio works at the speed of light. Lasers are also already used for some communication. No time travel involved. Edit: my comment above was posted before the message above was seen. What do you mean by "binary light frequency"? And, it's still not clear why you think/thought information would be received before it is sent. Edited May 4 by pzkpfw Link to comment Share on other sites More sharing options...
zapatos Posted May 4 Share Posted May 4 9 hours ago, GregJones said: I actually thought that if we sent binary light frequencies to a reflector deep in space via laser that the information could be received before the information was sent. Why did you think that? Link to comment Share on other sites More sharing options...
Halc Posted May 5 Share Posted May 5 (edited) On 5/4/2024 at 12:30 AM, pzkpfw said: What do you mean by "binary light frequency"? For instance, yellow-orange laser light has a frequency of about 5x10**14 Hz. The binary light frequency is equivalently 1x10**110001 Hz. How this makes a difference is of course a mystery, but adding mirrors to the situation is just going to add to the delays since the path is less straight. On 5/4/2024 at 12:30 AM, GregJones said: amazingly someone replied via the radio station having calculated how long it would take Yea, about 6 to 45 minutes depending on how far away Mars is at the time. 6-45 minutes later is not 'before it was sent'. Zero justification for the suggestion otherwise has been given. Edited May 5 by Halc -1 Link to comment Share on other sites More sharing options...
Sensei Posted May 5 Share Posted May 5 (edited) Quote Receive information before it is sent Do you receive an SMS response before sending a message with a question? Do you receive an email response before sending a question? If so, start playing the lottery.. or go to the casino.. Edited May 5 by Sensei Link to comment Share on other sites More sharing options...
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