As humanity’s furthest reach into the Universe so far, the two Voyager spacecraft’s well-being is of utmost importance to many. Although we know that there will be an end to any science…
With no way to fix the chip, the team instead split the code up so it could be stored elsewhere. Initially they focused on reacquiring the engineering data, sending an update to Voyager 1 on 18 April 2024.
It takes 22.5 hours for a radio signal to travel the 24 billion kilometres (15 billion miles) out to Voyager 1, and the same back, meaning the spacecraft’s operations team didn’t receive a message back until 20 April.
But when it arrived, they had usable data from Voyager 1 for the first time in five months.
Here’s a fun fact that I think of every time I read about light delay.
We assume the speed of light is the same in all directions but there’s no way to prove that it is.
It could be light speed is instantaneous in one direction, and half the speed we think it is in the reverse. Any test we could devise depends on information traveling in two directions, nullifying any discrepancies in light speed.
The speed of light in a vacuum unaffected by external forces such as gravity should be the same no matter what direction it is in. I’m not sure why it wouldn’t be. That’s like saying a kilometer is longer if you go East than if you go West.
However, it’s actually far more complicated than that, and much of it beyond my understanding.
There’s no reason it wouldn’t be. The point is that it’s impossible to prove that it is. There is no conceivable experiment that can be performed to prove the two-way speed of light is symmetric.
That’s not how anything works. It’s impossible to prove that the universe wasn’t created last Thursday with everything in place as it is now. There’s no point in assuming anything that can’t be proven has validity.
It’s just a thought exercise. There are several reputable YouTube videos on this topic. None of them claim that the speed of light isn’t the speed of light. They’re just demonstrating that we can’t prove it with current technology. Similar to the difficulty it took to finally prove that one plus one equals two. We know that’s correct, but it took years to prove it.
…but that’s exactly what you’re doing. The fact that light travels at the same speed in all directions cannot be proven. You’re the one insisting that it does.
I’m not insisting anything. I’m saying that, based on everything we know, the direction of light has no bearing on its speed.
Suggesting that it does just because we don’t have evidence that it doesn’t is no different, as I said, as claiming the universe was created last Thursday.
Maybe the speed of light doubles when it goes through the exact right type of orange. You can’t prove it doesn’t.
Synchronise two high-precision clocks at different locations. Transmit the signal from A to a receiver at B and then send a signal back (or reflect the initial signal) from B to A. Both locations will record the synchronised time that their sensors picked up the transmission. Then, compare their clocks.
Another interesting way to conceptualize it is that the speed of light is infinite and it’s causality/information that is limited to c. You shine a light at the moon and it takes 1.3 seconds for the “fact” that the light was turned on to propagate that far.
Cixin Liu imagines exactly that towards the end of the Three Body series. Among other things, which make the series worth absolutely slogging through at points.
What they did was close to wizardry.
https://www.skyatnightmagazine.com/space-missions/how-fixed-voyager-1
Here’s a fun fact that I think of every time I read about light delay.
We assume the speed of light is the same in all directions but there’s no way to prove that it is.
It could be light speed is instantaneous in one direction, and half the speed we think it is in the reverse. Any test we could devise depends on information traveling in two directions, nullifying any discrepancies in light speed.
The speed of light in a vacuum unaffected by external forces such as gravity should be the same no matter what direction it is in. I’m not sure why it wouldn’t be. That’s like saying a kilometer is longer if you go East than if you go West.
However, it’s actually far more complicated than that, and much of it beyond my understanding.
https://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html
That said, direction should not matter.
There’s no reason it wouldn’t be. The point is that it’s impossible to prove that it is. There is no conceivable experiment that can be performed to prove the two-way speed of light is symmetric.
That’s not how anything works. It’s impossible to prove that the universe wasn’t created last Thursday with everything in place as it is now. There’s no point in assuming anything that can’t be proven has validity.
It’s just a thought exercise. There are several reputable YouTube videos on this topic. None of them claim that the speed of light isn’t the speed of light. They’re just demonstrating that we can’t prove it with current technology. Similar to the difficulty it took to finally prove that one plus one equals two. We know that’s correct, but it took years to prove it.
…but that’s exactly what you’re doing. The fact that light travels at the same speed in all directions cannot be proven. You’re the one insisting that it does.
I’m not insisting anything. I’m saying that, based on everything we know, the direction of light has no bearing on its speed.
Suggesting that it does just because we don’t have evidence that it doesn’t is no different, as I said, as claiming the universe was created last Thursday.
Maybe the speed of light doubles when it goes through the exact right type of orange. You can’t prove it doesn’t.
This is slighlty different though, we only know the two-way speed of light, not the one way speed of light.
We only know that this trip, to and back, takes x seconds. We cannot prove that the trip to the mirror takes the same length of time as the way back.
The special theory of relativity for example does not depend on the one way speed of light to be the same as the two way speed of light.
Wiki
Why would the one-way speed be different? For what reason? Just because you think it’s possible?
Synchronise two high-precision clocks at different locations. Transmit the signal from A to a receiver at B and then send a signal back (or reflect the initial signal) from B to A. Both locations will record the synchronised time that their sensors picked up the transmission. Then, compare their clocks.
Another interesting way to conceptualize it is that the speed of light is infinite and it’s causality/information that is limited to c. You shine a light at the moon and it takes 1.3 seconds for the “fact” that the light was turned on to propagate that far.
Cixin Liu imagines exactly that towards the end of the Three Body series. Among other things, which make the series worth absolutely slogging through at points.