Submitted by SimplyZer0 t3_11wrxjm in space
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[deleted] t1_jczl64l wrote
[deleted]
solidcordon t1_jczm9qb wrote
When a signal is redshifted, the redshift will only become problematic for reception if the transmitter is accelerating away from the receiver at a (currently) unachievable rate or varying rate. (as long as your receiving antenna is capable of picking up the redshifted wavelength of the signal).
Varying rate / high acceleration could be factored in to reception with a wide enough spectrum receiving array.
A more significant problem is signal attentuation over the large distance, where the signal strength at the receiver is around the same magnitude of the background noise picked up.
Red shift is "not that strong" for the velocities we've achieved so far.
SimplyZer0 OP t1_jczp5pk wrote
Okay so you could simply just translate the signal and reciece the data.
a bit like our brain flips the image produced from our eye.
The problem is signal strength.
Okay so now i also have a very basic understanding of quantum superposition and quantum entanglement.
Schrodingers cat explains this very simply. In saying you can have a state that is both one or the other.
Or a 1 or a 0 in binary for example.
Until it is observed it can remain in both states.
But when it is observed it becomes 1 or the other.
Superposition and entanglement was also proved in 2022 nobel prize
If you could have computers that could read information in a quantam state would that fix the issue all together. The issue being data transfer at incredibly long distances in space (4.3 light-years)
solidcordon t1_jczr17z wrote
OK, so you want to receive a signal from alpha centauri.
There is a tiny red shift for light between here and there due to relative motion of the stars.
The sender would need a pretty powerful laser with a wavelength known to the receiver. They point the laser at the earth and send the message. In astronomical terms, this is not a long distance, the red shift is minimal and the receiver knows the red shift involved and the transmission wavelength of the light. The transmission is also consists of billions of photons all in the same wavelength. Sneding signals over interstellar distances would also involve repeating the message over the course of days with error correction bits.
It would not be a problem to filter out background noise over that range and correct for the minimal red shift.
As long as you are using a highly directional transmitter and know where your receiver is going to be when the signal should arrive, this works fine for distances of many thousands of lightyears. The transmitter power has to be increased to overcome signal attenuation over the distance. The next big problem would be stuff getting in the way. That's unlikely to be a problem under ranges of 100 light years, maybe up to thousands because space is big and mostly empty.
SimplyZer0 OP t1_jd02fq9 wrote
Ah okay this clears alot up for me in terms of short space transmission and shows how i can be used some what useful in current day technology, guessing the biggest limitation would be the speed.
Thanks enjoyed this
sees7seas t1_jd7f58h wrote
BTW radio waves travel at the speed of light.
DudeWithAnAxeToGrind t1_jd13t2e wrote
You can not use quantum entanglement for communication.
If you have two entangled particles, and you measure spin of one of them, you'll randomly get a result 50% of the time that it is up, and 50% of the time that it is down. Depending on that measurement, you know that the other particle will have opposite spin 100% of time, once measured by distant observer.
But for the second far away observer, doing that second measurement on the other particle from the entangled pair, they'll also see particle with either up or down spin randomly 50% of the time. Because, and this is important bit, the 1st observer is not forcing the spin to be either up or down. The 1st observer is measuring it and getting random result, and thus the 2nd observer sees random results from their viewpoint too. The 1st observer knows what the 2nd observer will get even before the 2nd observer measures the other particle on their end. But that doesn't communicate any information to the 2nd observer.
What this means is that the two observers can not communicate (i.e. exchange information) using quantum entanglement.
EDIT:
Think of it this way. Let say we have a set of two "entangled" dice. When I roll my dice, you'll always get the number on the opposite side on your dice.
So, I roll my dice and get 3. This means when you roll your dice, you'll get 4. I roll my dice again, and get 5. You roll your dice and get 2.
For both of us, those are just meaningless sequences of random numbers. I can not set my dice to 3, to force your dice to roll 4. I can only roll my dice, and get some random number; when you roll your dice, you'll get the number on the opposite side. This is what entanglement is.
This means, I can not communicate anything to you using these entangled set of dice. I have no control over what number will appear on my dice when I roll it, and thus I also have no control over what number will appear on your dice when you roll it. From your point of view, the signal you get is simply random noise.
Nerull t1_jd023qh wrote
If there is anything at all important to understand about entanglement it is that it does not transfer information.
SimplyZer0 OP t1_jd03sq2 wrote
Actually the ability to transfer information over entanglement was proven by the 2022 nobel prize in physics. And is a huge development in quantum computing.
Nerull t1_jd1uavq wrote
The 2022 Nobel prize in physics did no such thing. It wasn't about information transfer at all. It also isn't new - Nobel prizes are awarded for important work, not new work. On average Nobel prizes are awarded about 15-20 years after a work is published, if that work proves to be important enough. This one did, but its not some breakthrough that we didn't understand until now - it was awarded for work in 80s and 90s that has been the status quo in quantum physics for decades - and that physics, including the physics the prize was awarded for - confirm that no information can be transferred through entanglement.
The most recent paper cited by the Nobel committee in their summary of the work the prize was awarded for was published in 1999.
SimplyZer0 OP t1_jd24gca wrote
Yes this is all correct however you missed the part of the experiment that shows quantuam teleportation
Nerull t1_jd2ckmo wrote
Quantum teleportation is the transmission of a quantum state from one location to another through a classical communication channel. What does that have to do with information transmission through entanglement?
left_lane_camper t1_jd0g65d wrote
Unfortunately, quantum entanglement transmits no information and cannot be used directly for telecommunication.
It can, however, be used to help with encryption, which in turn aids (conventional, light speed or slower) communication.
EDIT: I see below someone already mentioned this and you responded to it. Unfortunately, the NCT is still entirely preserved with the work that the 2022 Nobel Prize in Physics was awarded for, though I have seen this mis-representation in popsci articles before. Violations of Bell's inequality are related to, but not equivalent to, violations of the NCT and demonstrating a violation of Bell's inequality is not the same as demonstrating a violation of the NCT. Indeed, the NCT is entirely compatible with those results and remains entirely unchanged by them.
Nerull t1_jd01uau wrote
Why would redshift corrupt the data? It just changes the frequency.
If you watch the carrier frequency of a satellite broadcast using a radio spectrum analyzer as it goes overhead you can watch it drift up and down. Satellite comms work just fine.
GetOnYourBikesNRide t1_jczhzck wrote
I think that the Doppler effect is accounted for in satellite communications. So, this might be more a question for computer science types who can explain the details of the algorithms they use in these kinds of communications.
boundegar t1_jczm61f wrote
However, the red shift would be extremely small. Any realistic velocity would be a tiny fraction of the speed of light.
Also, light and radio are the same stuff - just a different frequency
ExtonGuy t1_jd060j5 wrote
For almost all stars, the red shift (or blue shift) is less than 0.1%. That’s easily corrected at the receiver.
Anonymous-USA t1_jd0c7m7 wrote
Light and radio waves are all energy within the electromagnetic spectrum and differ only by radiating frequency.
Transmission over different cables and wires and space are a matter of convenience and using carrier materials that won’t dampen the desired frequency or power. For example, as you know, light can escape the mesh on your microwave oven but not the microwave energy itself. And materials that block light waves won’t block X-rays (though bone will block both, gamma radiation must be blocked with lead or higher density material). Etc. So different mediums can affect the signal. But space is mostly a vacuum.
Visible light can and is shifted down to microwave and, indeed, radio waves too. The greater the relative speed difference the greater the frequency shift.
dusty545 t1_jd0q15t wrote
The data isnt corrupt if you can account for the shift in your processing and playback.
Satellites have to correct for doppler shift when they process signals.
NoisyGog t1_jd26qob wrote
Signals used for communication use a few different systems, which would mitigate overall frequency change due to red and blue shift.
In analog systems, FM is the most common. This uses a carrier wave, and alters its frequency to impart information. That entire carrier wave would be higher or lower in frequency, but once you pick it up, the changes to it representing the information would still be fine. Imagine having to tune your radio to 94 MHz instead of 97MHz, but still receiving the same signal.
In digital transmission, it’s very common to have a “clock” pulse embedded in the signal. This clock effectively tells the receiving system what frequency it’s at, and where the data packet begins and ends.
Neither such system would have an issue with a red or blue shift.
reddit455 t1_jczh82t wrote
>If you try and send information between the 2 spaceships. If we use light or radio waves surely the data carried on those wavelengths are corrupt due to red shift.
you KNOW the transmission frequency. you know redshift. in theory you could correct for it.
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>Making it impossible for long distance data transfer in space between 2 objects that are moving away.
it's going to be "one way" both ways.. 20 light hour delay is not conducive to conversations.
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https://www.jpl.nasa.gov/news/engineers-investigating-nasas-voyager-1-telemetry-data
Voyager 1 is currently 14.5 billion miles (23.3 billion kilometers) from Earth, and it takes light 20 hours and 33 minutes to travel that difference.