Posted by dmitrybrant 8 hours ago
Many issues with the MIT game were discussed here:
https://physics.stackexchange.com/questions/43695/how-realis...
While the thread lists multiple issues, the issue that I found was with modeling temporal aspects of relativistic doppler (I also reported it on the github repo of the "slower speed of light" project, but that doesn't appear to be maintained):
https://github.com/MITGameLab/OpenRelativity/issues/17
In this game, it looks like the temporal component of the Doppler effect is modelled correctly.
How i got there:
The closest major galaxy to the Milky Way is Andromeda, and is 2.5 million! light-years away. And this is the CLOSEST galaxy, the universe is extremely big.
Of course that as you get closer to C, the traveling object will experience time dilation (relative to observer), so the time passed will be less. At 99.999% C, the traveler would take ~11,000 years to arrive to Andromeda.
So again, even at 99.999% C, 11K years seems like a LONG time to reach even the closest galaxy.
My reasoning was: the speed of light is pretty damn slow.
But then I realized: no, it's not the speed of light that is slow, is my frame of reference.
For us humans, 11,000 years seems like A LONG time, but for the universe is not that long.
The universe's age is estimated to be 13.8 billion years. 11,000 years is 0.0000007971 of the age of the universe.
An average human lives 70 years, 0.0000007971 of that lifespan is approximately ~0.4 hours, or 29 minutes, so it's not that bad.
So yeah, frame of reference matters.
If you can somehow accelerate/decelerate at a constant human-acceptable 1G, time dilation means almost anywhere is reachable in a human-lifetime.
That coincidence(?) could easily become false if we are accustomed to lower accelerations or lesser lifespans.
if we add more 9s, is it possible to reduce that number to within a human lifespan?
If you accelerate at 1g constantly for 1y you travel 0.5 light years. You do that for 10.5 years and you reach the center of the milky way. You do that for another 4 (~14 total) years and you are in the Andromeda galaxy, and you do that for another 10 years (~24 years total) and you reach what today is considered the edge of the observable universe.
By the time you get there you are basically traveling at a rounding error from C.
Can't we accelerate past 1G constantly? Or do we expend so much energy doing it that we can't realistically do it with today's technology?
Chemical rockets are currently the only thing that allow sustaining such accelerations briefly for human-size payloads, but the low exhaust velocity and exponential reaction mass requirement make sustaining it for days/months/years completely impossible.
You'd have to supply the energy externally (i.e. some sort of beam propulsion), but getting any significant fraction of g out of such a system (with human-sized payloads) seems unlikely within the next centuries, especially as the distance increases.
Or some form of ram scope, plenty of H everywhere, but those also have the issue of you collecting things while going at relativistic speeds.
Magic warp bubble tech is the bare minimum, and we're nowhere close to inventing that.
Increasing the acceleration a little bit more than that (eg to 1%) would make a difference.
Wouldn't that be only a few months on a decades-long journey at 1.01G vs 1G??
People always say that about speed of light stuff, but I don’t get it. Do you have any more examples of counterintuitive math?
Because what you’re describing is basically the equivalent to compound interest in finance. (e.g. investing $100 at 10% interest over 10 years results in $260)
- [pic](https://home.davidgoffredo.com/hackernews/proper-time-one-li...)
- [plot](https://home.davidgoffredo.com/hackernews/proper-time-one-li...)
1,000 seconds = ~0.01 days (~17 min)
1,000,000 seconds = ~11.57 days (~12 days)
1,000,000,000 seconds = ~11,574.07 days (~32 years)
1,000,000,000,000 seconds = ~11,574,074.07 days (~32k years)
Maybe it's just our human calendar/time unit rollercoaster (60*60*24*30*12) that's playing tricks on us here.
But it isn't intuitive, you're not used to numbers that big or that grow that fast.
Few things go from a million to a billion, especially when related to time.
At 99.999% of C, the Lorentz factor is ~223.6.
It grows pretty quickly as you add more 9s to the fraction. Every two additional 9s multiply the Lorentz factor by ~10.
So at 0.99999999999 c, it'd be ~223,607x.
2.5M years / 223,607 is: ~11 years
Of course this is all highly theoretical.
I've never quite wrapped my head around this and was hoping to get some insight from this simulation. But afaict, I'm not seeing this effect (press W for a bit, the A for a bit and it's not obvious I'm at a different orientation - if I look down at the ground the gridlines are still axial).
I don't know if I'm misinterpreting the math, or the simulation, or maybe the simulation is doing something to 'correct' for this behavior so things are more natural, or something else. Does anyone have any insight?
https://www.reddit.com/r/educationalgifs/comments/qq5cw7/coo...
We cannot play competitive multiplayer games globally, without 300ms ping. I dream of a world playing Black Ops 2 on a original PS3 in 2026 getting into a lobby because latency is low.
300ms feels extremely optimistic coming from my perspective of someone living on an island in SE Asia
https://wondernetwork.com/pings/Auckland
Your real world latency is going to be worse.
There is also a helpful FAQ which explains all the strange things happening, such as length contraction, time dilation, and color shifting: https://testtubegames.com/srel101.html
My favorite levels are #18 (which demonstrates time dilation), #26 (which demonstrates space warping), and #42 (which demonstrates retarded time https://en.wikipedia.org/wiki/Retarded_time ). All the levels are unlocked and you can skip to any level.
> A Slower Speed of Light is a first-person game prototype in which players navigate a 3D space while picking up orbs that reduce the speed of light in increments. Custom-built, open-source relativistic graphics code allows the speed of light in the game to approach the player’s own maximum walking speed. Visual effects of special relativity gradually become apparent to the player, increasing the challenge of gameplay. These effects, rendered in realtime to vertex accuracy, include the Doppler effect (red- and blue-shifting of visible light, and the shifting of infrared and ultraviolet light into the visible spectrum); the searchlight effect (increased brightness in the direction of travel); time dilation (differences in the perceived passage of time from the player and the outside world); Lorentz transformation (warping of space at near-light speeds); and the runtime effect (the ability to see objects as they were in the past, due to the travel time of light). Players can choose to share their mastery and experience of the game through Twitter. A Slower Speed of Light combines accessible gameplay and a fantasy setting with theoretical and computational physics research to deliver an engaging and pedagogically rich experience.
A Slower Speed of Light (2012) - https://news.ycombinator.com/item?id=40332586 - May 2024 (59 comments)
What if we could reduce the speed of light - https://news.ycombinator.com/item?id=26309517 - March 2021 (1 comment)
A Slower Speed of Light (2012) - https://news.ycombinator.com/item?id=17169262 - May 2018 (15 comments)
A Slower Speed of Light - https://news.ycombinator.com/item?id=4731749 - Nov 2012 (105 comments)
"A Slower Speed of Light" Game Trailer - MIT Game Lab - https://news.ycombinator.com/item?id=4714779 - Oct 2012 (1 comment)
I feel like a rule of vibecoding would be that you shouldn't do it for the core of a product, the quality is just not there yet. Even if it is, your core contribution should be what LLMs would train on, rather than being their output.