this is fine, but I would like to see the deceleration for the second half of the journey
Time Dilation Formula / Calculator
41–50 of 54 posts
Re: Time Dilation Formula / Calculator
#42Author's description of twin paradox is incorrect. In fact, the paradox is not described at all. The paradox is that since motion is relative then from both twin's perspective the other twin goes on a journey and ages slowly. So why it is that on returning, only the traveling twin has aged slowly? The answer is that both twins indeed see each other age slowly but for the traveling twin to come back they have to slow…
Are you suggesting that two people in a shared inertial space when venture into other intertial frames but ultimately end up in a same frame later will agree on how much time has passed in between?
Because I lowekey believe this to be true but don't have means to prove it.
Re: Time Dilation Formula / Calculator
#43Author's description of twin paradox is incorrect. In fact, the paradox is not described at all. The paradox is that since motion is relative then from both twin's perspective the other twin goes on a journey and ages slowly. So why it is that on returning, only the traveling twin has aged slowly? The answer is that both twins indeed see each other age slowly but for the traveling twin to come back they have to slow…
The twin paradox holds in a Pacman universe where there is no change in direction. The main issue with the twin paradox is that it demonstrates where our euclidian intuition fails us. There are several interpretations on how to resolve it, but they are all just flawed lenses, intended to help you along a curriculum until you understand the math, and also understand the limitations of intuition. The 'turn around' expl…
Can you expand on this? I was only ever taught the "turn around" explanation.
Re: Time Dilation Formula / Calculator
#44Earlier quoted context omitted.
I'm assuming that ben_w is referring to the blue shift in the CMB that you will see in front of you. And pair production is the process of turning sufficiently high energy light into matter. https://en.wikipedia.org/wiki/Pair_production https://www.imperial.ac.uk/news/149087/scientists-discover-t... But I've never given thought to the fact that for some observers the microwave background are low energy photons, and f…
Correct. > Seems like another one of those relativity related paradoxes. Only fast-moving observers (relative to the CMB) are seeing constant pair production from the CMB photons? Both observers agree about pair production. Pair production obeys conservation of momentum and energy — although the equations allow both to be conserved with two photons interacting, the practical effect here is CMB photons interacting wit…
I was under the (probably mistaken) assumption that high enough energy photons could spontaneously turn into an electron and positron. But it is sounding like you need at least two photons to do that. And maybe those photons can't be traveling in essentially the same direction for that to occur? Like the cross products of the momentum of each photon needs to be above a threshold or something?
Re: Time Dilation Formula / Calculator
#45Author's description of twin paradox is incorrect. In fact, the paradox is not described at all. The paradox is that since motion is relative then from both twin's perspective the other twin goes on a journey and ages slowly. So why it is that on returning, only the traveling twin has aged slowly? The answer is that both twins indeed see each other age slowly but for the traveling twin to come back they have to slow…
The twin paradox holds in a Pacman universe where there is no change in direction. The main issue with the twin paradox is that it demonstrates where our euclidian intuition fails us. There are several interpretations on how to resolve it, but they are all just flawed lenses, intended to help you along a curriculum until you understand the math, and also understand the limitations of intuition. The 'turn around' expl…
>The twin paradox holds in a Pacman universe where there is no change in direction.
That is awesome, I've always wondered about special relativity in a flat torus world. Do you have a recommendation for reading more about this?
Re: Time Dilation Formula / Calculator
#46Earlier quoted context omitted.
I'm not one to nitpick tools to grok things but I think this could confuse more than help! Because everything is relative to something else - and your example of the pendulum on a ship is suggestive of a "real" velocity, which does not exist. I think a far easier scario to imagine is some ship flying away from Earth, and this ship has a magic button to release an impulse enough to give it a 10% of the speed of light…
"If our ship travels 20,000 light years in 40 years (from the perspective of those on the ship) then that would take a "real" 20,000 years from the perspective of those on Earth" This part just breaks my brain. I've been reading about this stuff for decades, and it just does not compute. It's also a little funny because there's basically zero incentive for the folks on earth to send astronauts away at near-light spee…
>there's basically zero incentive for the folks on earth to send astronauts away at near-light speed, as they'd never realize the benefits of the mission.
s/earth/Milky Way/
Re: Time Dilation Formula / Calculator
#47Woah, thanks for all the comments on this little calculator I built yesterday afternoon. I'll digest everything and see what improvements I can make!
Re: Time Dilation Formula / Calculator
#48Earlier quoted context omitted.
The twin paradox holds in a Pacman universe where there is no change in direction. The main issue with the twin paradox is that it demonstrates where our euclidian intuition fails us. There are several interpretations on how to resolve it, but they are all just flawed lenses, intended to help you along a curriculum until you understand the math, and also understand the limitations of intuition. The 'turn around' expl…
Can you expand on this? I was only ever taught the "turn around" explanation.
All I can offer without going into the weeds is that it is not the shape of the paths, but mearly the relative length of two paths though spacetime that matters.
Proper time and proper acceleration is possibly a pathway in flat spacetime?
Learning that the order, timing, and sometimes causality of events is also relative tends to be a barrier, thus some of these didactic half truths are useful.
The "Einstein train paradox" is the classic intro to the relativity of simultaneity if you aren't familiar.
In the SR case, proper acceleration is possibly the better option.
Re: Time Dilation Formula / Calculator
#49How do you stop so you don't go whizzing past Alpha Centauri at near light speed? :)
I was wondering about this too—it's super interesting! Did you create this? Could you add graphs showing acceleration and deceleration? Also, this might be a dumb question, but how does mass factor into the energy calculations? I would love to see graphs that include the multiple stages of travel (acceleration and deceleration) as well as the mass of various kinds of fuel required for different propulsion systems suc…
Hey, I created this and yes I want to include charts if you want to decelerate too so you don't go flying past. I knocked out this initial version yesterday afternoon and already planned to add this. Might see if I can do it today.
Re: Time Dilation Formula / Calculator
#50this is fine, but I would like to see the deceleration for the second half of the journey
I do intend to add this to the calculator