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Question: Real Time Transmission of Video - Space Travel
Vanity | 6/12/2017 | Vanity

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...


TOPICS: Miscellaneous; News/Current Events; Unclassified; Your Opinion/Questions
KEYWORDS: brothers; my; question
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To: FreedomStar3028

The universe could already be over on the other side, someone could have initiated a vacuum decay.


21 posted on 06/22/2017 10:18:30 PM PDT by Axenolith (Government blows, and that which governs least, blows least...)
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To: Swirl

No it won’t! The transmission itself isn’t travelling away from the viewer at the speed of light. Only the ship is. The transmission is travelling in the opposite direction relative to every position of where the ship IS when broadcasting. The waves don’t travel with the ship. They are INDEPENDENT of it. Thus not relative to the ship, but to the viewer.


22 posted on 06/22/2017 10:19:59 PM PDT by FreedomStar3028 (Somebody has to step forward and do what is right because it is right, otherwise no one will follow.)
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To: Vendome

The sci-fi juvenile novel “Time for the Stars” by Robert A. Heinlein postulated that twins could use psychic powers to communicate simultaneously if one traveled in a ship at light speed while the other stayed on Earth. Interesting idea.


23 posted on 06/22/2017 10:22:09 PM PDT by \/\/ayne (I regret that I have but one subscription cancellation notice to give to my local newspaper.)
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To: Swirl
Assuming that the speed of the space craft remains much less than the speed of light, the time within video will be stretched as distance from earth increases. So motion as viewed from the broadcast will be slowed.

No. The relative rates of time passage are strictly dependent on relative speed and do not depend on distance whatsoever. A message sent from a craft traveling at 1/2 light speed will be slowed by the same amount ("the time within the video") regardless of whether the source is a foot away or a light year. This holds true no matter what the difference in relative speed is; it simply isn't noticeable when the velocities are very close to the same value. If we could actually distinguish it, the time rate of the guy walking toward the front of a moving bus is slower than that of the guy sitting in a seat, and both are slower, but not equally so, than that of a guy standing on the street as the bus goes by.

24 posted on 06/22/2017 10:22:11 PM PDT by calenel (The Democratic Party is a Criminal Enterprise. It is the Socialist Mafia.)
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To: cba123
So would the radio/light waves be actually received here, at 1 percent of their original velocity? Or would the radio waves be received here, at the speed of light here?

The latter. Light always travels at the speed of light (in what ever medium), regardless of the speed of the sender or observer. It would be red- or blue-shifted due to the Doppler effect. But even if you had two parties traveling at 99% of the speed of light in opposite directions, not only would light transmitted between the two still appear to travel at the speed of light, neither one would see the other as traveling faster than light. They might see each other traveling at 99.99% (I didn't do the actual calculation, just giving an example) of the speed of light, but not in excess of it.

25 posted on 06/22/2017 10:36:46 PM PDT by calenel (The Democratic Party is a Criminal Enterprise. It is the Socialist Mafia.)
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To: \/\/ayne
The sci-fi juvenile novel “Time for the Stars” by Robert A. Heinlein postulated that twins could use psychic powers to communicate simultaneously if one traveled in a ship at light speed while the other stayed on Earth. Interesting idea.

Actually, while they were traveling, beyond a certain relative velocity they could not communicate due to time dilation slowing down the one on the ship too much, but when they slowed down to check out a planet they could sometimes reestablish communication. The benefit of the twin telepathy was that it was instantaneous rather than limited to light speed, so they could communicate without long delays.

26 posted on 06/22/2017 10:42:31 PM PDT by calenel (The Democratic Party is a Criminal Enterprise. It is the Socialist Mafia.)
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To: Vendome

There was a sci-fi movie for kids that addressed this issue of delayed or late transmissions receptions. I think it was called “The Explorers”. Pretty sure it had River Phoenix in it.

All about their communicating with an alien spaceship whose teenage inhabitants talked like people in TV ads from the 1950’s (which were the transmissions they were receiving and learning from out in deep space).

If we go fast enough, perhaps we will run into the first season transmissions of “Twilight Zone”.

Don’t forget to bring some popcorn, because “In Space, There Is No Popcorn”.


27 posted on 06/22/2017 10:58:31 PM PDT by MadMax, the Grinning Reaper
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To: Vendome

Its all relative. On earth the live video would be considered delayed, not much from the space station but from mays it would be about 14 minutes.


28 posted on 06/22/2017 11:04:59 PM PDT by aft_lizard
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To: Vendome

Maybe this will help. Maybe it won’t.

https://en.wikipedia.org/wiki/Relativity_of_simultaneity


29 posted on 06/22/2017 11:07:26 PM PDT by Moonman62 (Make America Great Again!)
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To: noiseman
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. Since time passes much more slowly for the spaceship crew at near light speed than it does for those on Earth, would the Earthbound viewers see the broadcast keep slowing down as the craft approached light speed, until eventually it seemed to be running at a fraction of real-time? My guess is that this is precisely what would happen, but curious if anyone has other ideas.

GPS satellites move at way less than the speed of light, but GPS calculations still need to account for Special and General Relativity. Special Relativity slows the satellites' clocks by about 7 microseconds a day, but General Relativity speeds them up by about 45 microseconds/day. The net is, they gain about 38 microseconds per day. From this link:

To achieve this [high] level of precision, the clock ticks from the GPS satellites must be known to an accuracy of 20-30 nanoseconds. However, because the satellites are constantly moving relative to observers on the Earth, effects predicted by the Special and General theories of Relativity must be taken into account to achieve the desired 20-30 nanosecond accuracy.

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly (see the Special Relativity lecture). Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion [2].

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture). As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.

The engineers who designed the GPS system included these relativistic effects when they designed and deployed the system. For example, to counteract the General Relativistic effect once on orbit, the onboard clocks were designed to "tick" at a slower frequency than ground reference clocks, so that once they were in their proper orbit stations their clocks would appear to tick at about the correct rate as compared to the reference atomic clocks at the GPS ground stations. Further, each GPS receiver has built into it a microcomputer that, in addition to performing the calculation of position using 3D trilateration, will also compute any additional special relativistic timing calculations required [3], using data provided by the satellites.


30 posted on 06/22/2017 11:25:40 PM PDT by cynwoody
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To: Vendome

No. It would be from the past. Unless the transmisdion was somehow done using pairs of entangled particles in which case it would be live until you ran out of them or they underwent decoherence.


31 posted on 06/22/2017 11:29:12 PM PDT by AndyTheBear
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To: KC_for_Freedom

Thnx


32 posted on 06/22/2017 11:36:01 PM PDT by Vendome (I've Gotta Be Me - https://www.youtube.com/watch?v=wH-pk2vZG2M)
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To: Vendome

I have a better question...

Exactly how do jet engines propel space craft in a vacuum?


33 posted on 06/22/2017 11:43:38 PM PDT by Sontagged (Lord Jesus: please expose, unveil and then frogmarch Your enemies behind You as You've promised...)
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To: Sontagged

I don’t think there is a jet engine typical.

It is liquid fueled I believe...


34 posted on 06/22/2017 11:48:55 PM PDT by Vendome (I've Gotta Be Me - https://www.youtube.com/watch?v=wH-pk2vZG2M)
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To: Vendome

If you achieve the speed of light which is quite impossible your will never receive a reply least you slow down to less than the speed of light. However that is not “gonna” happen unless you are on the Stare-ship Enterprise that defies all known physics.

I personally think our galaxy and universe is full of life. Only physics is the reason we do not have contact today. In the advance of science we only came out of caves 20,000 years ago. Other species are without doubt out their with science millions of years beyond ours. They have not contacted us because simple physics of interstellar travel make it impossible. As our science becomes better we may well detect their electromagnetic transmissions. I would suspect they are thinking the same thing, “are we alone.”

But even more sad would be a species that knows they are not alone and does not really give a damn as we are so far beneath them to be nothing but strange curiosities.


35 posted on 06/22/2017 11:55:13 PM PDT by cpdiii ( Deckhand, Roughneck, Mud Man, Geologist, Pilot, Pharmacist. CONSTITUTUTION IS WORTH DYING FOR!)
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To: Vendome
Technically, nothing is "real time". If I'm 10 feet away from you broadcasting a message over radio, you receive it 0.00000001 seconds later. So I'm actually broadcasting to you from 0.00000001 seconds in the past. Similarly, if I'm a whole light year away, I'm broadcasting to you a year in the past.
36 posted on 06/23/2017 12:09:09 AM PDT by Telepathic Intruder
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To: Telepathic Intruder

Nice


37 posted on 06/23/2017 12:16:56 AM PDT by Vendome (I've Gotta Be Me - https://www.youtube.com/watch?v=wH-pk2vZG2M)
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To: Vendome

Thrust is not possible in a vacuum.


38 posted on 06/23/2017 12:17:52 AM PDT by Sontagged (Lord Jesus: please expose, unveil and then frogmarch Your enemies behind You as You've promised...)
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To: Vendome

We used to have a message board called “FTL” (Faster Than Light) on one of the Sacramento Citadel (and other) BBS’s back in the 1980’s. All us smarter than everyone else teenagers would go on and on about how much we THOUGHT we knew about physics and try to outdo the other young brains full of mush that thought they knew more too. Ah, those were great days.


39 posted on 06/23/2017 12:55:39 AM PDT by lefty-lie-spy (Stay metal. For the Horde \m/("_")\m/ - via iPhone from Tokyo.)
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To: Sontagged

Think rockets and forget about jet engines once you get to the edge of the earth’s atmosphere. High flying aircraft like the SR-71 and U2 just barely get by, and they have specialized engines and body styles that let them still get lift and thrust at those altitudes.


40 posted on 06/23/2017 1:09:58 AM PDT by lefty-lie-spy (Stay metal. For the Horde \m/("_")\m/ - via iPhone from Tokyo.)
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