Posted on 06/22/2017 9:45:54 PM PDT by Vendome
So, here is the dumb question my brother posed:
If a ship leaves earth and transmits "LIVE" video as it travels deep into space, would the transmissions continue to be live and real time even as it traveled months and years away from earth?
At what point does that transmission actually delay or become part of the past?
Bonus question: Assuming the craft continues travel directly away from earth, if it stopped transmitting and then restarted transmitting would that now be real time?
Caveat: I don't know the distance that makes the transmission now a part of the past...
Would a pistol fired in space have recoil?
Regardless of where you are in the universe, it is always now.
And, we never see the same rainbow
The only flaw in this theory is that too many people who theoretically operate in the same timeline (Earth, 2017) seem to see totally different things when looking at them through highly distorted political lenses. ;-)
Combustion is most definitely possible in a vacuum. That is where oxidized fuels come into play.
Of course. You ask this seriously? C’mon FRiend!
I know that. I was replying to Sontag’s post above to a YouTube link containing the half-baked idea that “Thrust not possible in a vacuum:”
The intention being to gain a recognizence that for every action there’s an equal and opposite reaction. The ejection of the bullet from the barrel of the gun cause an equal and opposite reaction on the mass of the gun self. Thus, ejection of gas from a container causes an opposite reaction on the container, vacuum or not, because gas has a mass.
Thank you for the clarification. I missed the snark. I’m happy to hear we have no Dem-dumbs here. Cheers.
We would know immediately if the sun vanished, because the earth would be flung out of its orbit. The sun’s gravitation, which keeps the planets in their elliptical orbits, is not relative to the speed of light. That’s part of the thought experiment that led Einstein to postulate his theory of space-time.
Assuming we were still alive to observe it (and still in the same orbit — which we decidedly would NOT be), the light from the sun would expire about 8.3 minutes after the sun did.
Sound travels at approximately 1100 feet per second. So say you are at a stadium concert, and are 275 feet away from the stage. Are you listening to the concert “live”, when the sound has been delayed by a quarter of a second to your seat?
The answer to this question answers your original question.
Also, “live” in the parlance of radio and TV means that it wasn’t taped and rebroadcast, but is sent as it is received.
I think I get the thought experiment you’re describing.
And we have examples of how it actually works through all of our deep-space probes. Voyager has been transmitting, all the time, since it’s launch.
What we get are properly timed bleeps and bloops, but they are delayed. If the probe was building speed, as it got faster the transmissions would be slower and start to get garbled. But it’s not getting faster, so everything is “real time” but delayed.
How is this possible ? If it’s broadcasting all of the time, then we should see the transmissions get slower as delay is accumulated !
What you’re talking about is basically a time-travel experiment. Those in the ship would be able to accurately tell us our future (Even though our future.. I dunno.. in the vacuum of space where there is nothing to report but the ticking of a clock)
And if that crew went out to months of delay, then turned around and came back, when they landed they would be a month ahead.. somehow.
We both know that’s not possible, but it’s time to look for an explanation of why or why not.
Actually ALL LIVE TV is in the past. There is always a small delay of a fraction of a second or more before you see it on your TV....
And even if it is only .2 second delay - it is still the past....by .2 seconds......the delay increases with distance as many here have clarified.......
As a science teacher in the 60’s, I’d point out to my students: “Look at the stars in the sky. What you see is not really there. You are seeing where the stars were ages ago.
Not only that. What you see now, as a whole, NEVER EXISTED AS YOU NOW SEE IT. Why? Because what you are seeing of one star came from a million years ago, while the light from the star that appears to be right next to it left 10 million years ago, and both have moved over that time. You are actually seeing a composite of what existed at different points in time, and never existed as you view it now.”
The earth based receiver would have to compensate, not for the delay, but the modification to the signal. The wavelength would get longer the faster it went. It’s a process called “redshifting”. The information itself would also get slower in it’s reception. One frame of video which in a 30 frame per second video takes naturally 1/30 of a second to watch. Viewing video is based on that 1/30 of a second transmission speed per frame being attainable. Eventually the frame reception would slow down to that one frame takes significantly longer than 1/30 of a second to receive. This would cause an effect like watching a video in slow motion. So imagine if you’re watching live, as it accelerates, you’ll have to compensate for signal redshift and even then, you’ll get a slower and slower frame rate and stuttering audio till it becomes unwatchable.
In the future, video would have to be sent with some form of signaling to indicate the entire message has been sent so the viewer can compile and watch it as close to real time as possible.
It's relative.
Its all relative.... that pesky Einstein.
“Interesting question, but what would be even more interesting to ponder is what would happen if a spaceship crew began to broadcast live video/audio as they launched, and then accelerated to near the speed of light.”
That’s where my mind went as well.
No. You would get a Doppler shift immediately. Your video circuits would have to compensate by slowing down the frame rate slightly. The further out you got, the greater would be the delay between what happened at the source and what is seen at the receiving end.
No it wouldn't. It would be Doppler shifted. If the craft is moving away, it would slow the video rate some small amount. If the craft was moving toward you it would speed up the frame rate a small amount.
The higher the velocity relative to the receiving end, the greater would be the change in the frame rate.
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