Imagine a sender sending information faster than light to a reciever 3 minutes away in time (3 light minutes in distance), but the receiver gets that information instantenously. Now what if, upon receiving that information, the reciever sends it back instantanously to the original sender, who is still 3 light minutes away and tells him not to send the original information? The original sender would receive this second signal 3 minutes before he actually sent the original one. It's a paradox, it couldn't happen. Why would the second signal be sent if the 1st was never sent? But then, why would 1st one not be sent unless the original sender was told not send it by the second signal? But then why would this happen if the 1st signal was never sent? but then, but then, but then.............. This is my understanding of what would happen. I could be wrong though.
I think that you've gotten mighty confused somewhere.
you're suggesting that if you could send a signal faster than light that it'd arrive in the past?
so if you're communicating over a distance of 3 light minutes, then the person receiving the message 3 minutes into the past? then they reply, and you get the reply 3 minutes before they sent the reply. -i.e 6 minutes before you sent the message.
it's just simply not true. the earth and the moon exist in the same time just different places, and different places aren't in different times... the earth is not three minutes behind the moon, and the moon is not three minutes behind the earth, (nor is it the second or so behind or in front than it takes for light to reach here from the moon).
the earth and the moon exist at the same time.
what actually happens is the view of the earth that you have from the moon is actually three minutes into the past, and the view of the moon that you have from the earth is three minutes into the past. (well, a second -just over).
when you look at an object a distance away, you don't see the object you see a reflection of the light, and you see that light when it reaches you.
basically if you were three light minutes away from the earth and you saw an alien land, you could send a message faster than light, (instantaneous if you like), but your message will be being sent three minute after the even has happened. because that's how long it took for the light to reach you.
looking at a distant object only tells you what the object looked like at the time the light was reflected off of that object.
Kind of like you're looking into the past.
so if I send a message to a place 3 light minutes away saying wave a red flag, they will get that message, wave a flag instantly, but it'll still be three minutes until I see the flag waving...
if I send a message saying wave a red flag, they wave a flag and send a message to say OK, then I could send another message to say I can't see the flag, because I can't, I won't see it for the three minutes it takes for the light to get to me.
I could send a message saying wave a flag.
they do, and send back message saying that they are waving a flag, though I can't see it because the light hasn't reached me yet. then I see the flag and say take it down. they do take it down, but I can still see if for three minutes, because that's the time it's taken for the light to get to me, removing the source of the reflected light isn't going to interrupt the photons that are already travelling my way.
if I wanted to see the flag for 1 minutes only I 'd need to send a message saying wave a flag, then a minute later send a message saying remove the flag, 3 minute after message 1, (and 2 minutes after message 2) I'd see a flag, a minute after (4 minutes after message 1 and three minutes after message 2).
basically, if I wanted to seethe flag for only a minute I'd have to tell them to remove the flag, before i'd even see it, this wouldn't be a paradox.
at least no more of a paradox than it is to see lightening and hear thunder seconds afterwards. it's just because one method of transmission would be faster than another.
I could no more ask for a flag not to be seen after it's been put up three light minutes away, by sending a take down message before I actually see it). than I could see lightening and try to prevent the thunder, I can't prevent it because it's already happened. just the physical phenomenon hasn't reached me yet due to the transmission time of sound being slower than light.