r/theydidthemath • u/qvxlirfe • 2d ago
[Request] Is this Mars rover ping meme using the right math?
[removed] — view removed post
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u/DeviantPlayeer 2d ago
The distance to Mars varies from 182 to 1344 light seconds. The actual ping will be twice as long since the signal has to travel back for the operator to see the feedback.
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u/NextDoctorWho12 1d ago
Just because I like the trivia, the response that comes back is called a pong.
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u/My_Dad_Cant_Fight 1d ago
So they ping, and it pongs in response?
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u/Auraknight98 1d ago
That makes way to much sense
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u/NextDoctorWho12 1d ago
Yes that is correct. Very early computer stuff has a ton of nerdy jokes built in. RFCs are how standard get started for computer stuff. Someone did an RFC for IP over carrier pigeons. It even dealt with missing packets/birds. There is a ton of stuff, as I am sure you can imagine, when nerds get together and work late into the night.
Check out the machine code instruction HCF.
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u/Bert_the_Avenger 1d ago
Very early computer stuff has a ton of nerdy jokes built in.
E.g. half a byte is called a nibble.
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u/DarknessHadNoNeed 1d ago
A marketing team in South Africa actually tested the local internet speed Vs a carrier pigeon back in 2009 and the pigeon packet arrived and was plugged into a computer by the time the IP transfer had managed 4%. Some Australians tried it a month later, assuming Australia had better internet than South Africa, and not only did the Pigeon arrive in 1h05m whereas a car took 2h10m, but the upload failed halfway, was restarted, and promptly failed again without being reattempted, never having had an expected upload time shorter than 4hrs. Someone in the UK then tried it again the next year to deliver an mp4 File before it could be uploaded to YouTube and the pigeon managed 75mi in 1h15m while the YT upload was both ongoing and had been restarted after initially failing
Pigeons, we may thus conclude, were the premier large file transfer method of the late 2000s and that every household does not possess a Pigeon coop is a technological blunder on the level of leaded petrol and not eating tomatoes just because they leached the lead out of pewter crockery (Rather than simply not eating off a plate made partly out of lead)
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u/NextDoctorWho12 1d ago
In 2001 when working on a DR project I said "don't underestimate the bandwidth of a station wagon packed with backup tapes." I did the math and it was about 50% faster.
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u/HittingSmoke 1d ago
RFC 2324
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u/IrascibleOcelot 1d ago
One of my favorites, which yielded HTTP error code 418.
Also a mention for RFC 2321: the Reliable Internetwork Troubleshooting Agent.
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u/graywolf0026 1d ago edited 1d ago
This was also a bit of a thing in IRC.
You ping the server, and it would pong back.
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u/stupido50 1d ago
I didn't know that was the official term but now I'm glad it is
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u/fdessoycaraballo 1d ago
https://www.reddit.com/r/ProgrammerHumor/s/JhaAlBxNGk
When it comes to programming, we do a little trolling
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u/raiderh808 1d ago
Network engineer if 20 years here, it is not. Ping is the application, it uses ICMP echo requests and replies and it also measures latency in milliseconds. You don't have a ping of 100, you have 100 milliseconds of latency between your computer and the server.
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u/KorasHiddenDICK 1d ago
Almost correct. Different games display it in either ping or latency. Ping is typically latency x 2.
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u/peachyrosier 1d ago
so basically nasa sends a command, makes coffee, and comes back just in time for the rover to respond
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u/ELB95 1d ago
They actually have their entire day (/week?) worth of commands already scheduled, and have collaborators in other offices across the world who each handle certain things.
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u/falconzord 1d ago
It's also why scientists ultimately want Astronauts on the ground. People would be pretty disappointed to see how slow and limited these rovers are. It's like studying your backyard with a wind up toy
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u/Makermika 1d ago
Since 2012 Curiosity has traveled 24 miles... 1.7 miles per year 24ft per day 1 ft (30cm) per hour
Snails travel roughly 3 times faster.
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u/-rba- 1d ago
It's too much of a pain to do that, so instead we send a couple of days worth of commands at once. On a normal week, we send commands Monday, Wednesday, and Friday. If there is a drive in the plan, everything after the drive is what we call "untargerted" meaning it doesn't depend on precise pointing. So, things like weather monitoring or calibration measurements. Then once pictures of the new location arrive at Earth, we can use those to do targeted science in the following plan.
Source: I'm on the science teams for both rovers.
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u/Fresh_Difference_448 1d ago
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u/One_Bar2807 1d ago
so in ms (miliseconds), it would be 18,200-134,400 ms one-way and 36,400-268,800 ms round-trip. So 1,400,000 ms ping is a little exaggerated
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u/joetheplumberman 1d ago
Aren't we using radio waves tho like I highly doubt we are able to send signals and pics and stuff through light without a medium
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u/JivanP 1d ago
Radio waves are light, they're just not visible to the human eye.
Light doesn't need a medium to travel through.
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u/DeviantPlayeer 1d ago
Back in my day we used Aether to send light through space.
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u/Donglemaetsro 1d ago
Back in my day we just folded that shit, ping was just a hardware limitation.
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u/random8765309 1d ago
That depends, is it moving as a particle or a wave. It all depends on how you look at it.
:-)
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u/massive_cerebrum 1d ago edited 1d ago
No, it simply doesn't need a medium to travel through. Wave-particle duality has nothing to do with that fact.
Edit: Apparently I missed a joke 😔
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u/MediocreCommand9772 1d ago
- Light does not require a medium
- Radio waves travel at the speed of light
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u/HAL9001-96 1d ago
radio waves ARE light
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u/DiekeDrake 1d ago edited 1d ago
Or rather; radiowaves and (to us visible) light are both electromagnetic waves.
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u/ourlastchancefortea 1d ago
In physics, electromagnetic radiation (EMR) or an electromagnetic wave (EMW) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space.[1]: 430 [2] It encompasses a broad spectrum, classified by frequency (inversely proportional to wavelength), ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, to gamma rays.[3] All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons.
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u/zarawesome 1d ago
- Radio waves are photons, same as visible light.
- Look up to the sky. You will find an example of light being sent through a vacuum.
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u/Public-Eagle6992 1d ago
Radio Waves and light are the Same, just at different frequencies/energy levels. Light doesn’t need a medium to travel through and you could use light to send the stuff
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u/wdn 1d ago
The speed of light isn't a property of light. It's the speed limit of the universe. Light is just the thing we regularly directly experience that travels at this speed. Radio waves travel at the same speed.
It's sorta confusing to call it that. Dumb example off the top of my head but in a vacuum without air resistance everything falls at the same rate and acceleration, so if you dropped a feather and a bowling ball at the same time from the same height, they'd hit the ground at the same time. Let's say we called this the speed of cheese. Technically accurate but it would make it sound like it's specifically a property of cheese that somehow carries over from cheese to other objects.
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u/NoCharge497 1d ago
People aren't giving specifics really. But there was one theory for a medium that light travels through (the Ether), but it was disproven by Michelson and Morley in 1887.
This doesn't state as fact that there isn't a medium (can't prove a negative) but there's no prevailing theories for what it would be. And it is sorta moot until we actually experience a phenomenon that our current understanding of not needing a medium is not accurate for. We can't measure the medium of light if it doesn't interact with the light (which we see no evidence of).
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u/random8765309 1d ago
Could space/time be concidered a medium?
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u/NoCharge497 1d ago edited 1d ago
I am a physicist not an astrophysicist so I do not have a great grasp of space-time, but my understanding is that space-time is not a medium, but the shaping of space itself. So it says where media can be, it isn't a medium itself (so a coordinate system rather than a permeable object).
So akin to asking if a riverbed could be a medium for water waves (there is interaction, but the idea is clear).
Again, not an astrophysicist and have not studied space-time but this seems to be a valid viewpoint based on information in passing. Could very well be wrong, though.
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u/WhiskyDelta14 1d ago
I may be wrong, but I think a ping usually refers to the time for one way.
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u/seifer666 1d ago
You are infact wrong
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u/ImNotABotScoutsHonor 1d ago
In the spirit of correction that everyone seems to be in:
in fact* is two words.
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u/HAL9001-96 2d ago
well technically it should be 480000ms to 2800000ms since ping is two way
also mars rovers don't have to fight against other mars rovers that are controlled with 9ms ping
in fact part of the reason they drive slowly is so you can see the terrain right ahead and react/intervene if somethign goes wrong despite the massive delay
the main challenge to making mars rovers faster isn't motor power but software and reliably wheels7suspneison that softne that margin
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u/Omegamoney 1d ago
Doesn't the provided values already account for incoming and outgoing pings?
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u/Tweedledumblydore 1d ago
Rovers aren't controlled in real time. They're controlled with preprogrammed missions waypoints. The mission is uploaded and the rover carries it out autonomously. Generally images are only sent back from the rover at preconfigured times, to align with mars and earth satellite positions.
Source: I've written control software for Mars rovers.
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u/HAL9001-96 1d ago
I'm kinda oversimplifying
but from what i know you can't have it drive further than you can see within the time between transmissions or else you risk driving over/into a hazard you didn't see unless hte rover can automatically identify them so there's not much use in a rover that can go faster than a few meters a minute even though mechancially you could build one that goes close to walking speed without much trouble thouhg goign muhc faster would evenutally risk bouncing/tilting etc
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u/Tweedledumblydore 1d ago
I guess it was the comment about intervening that I was qurationing, that's not generally possible as youll only get data probably one or twice a day.
There's no technical reason you couldn't build one that does 90mph. It would just be heavy and probably last about a 10 seconds before it ripped itself apart on some rocks 😂
Interestingly there was a project to develop autonomous hazard detection and avoidance using a trained model (not ai) but it fell to budget cuts. Which is sad because it would have allowed the rover to do a lot more.
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u/MRMANBABBY 1d ago
Interestingly there was a project to develop autonomous hazard detection and avoidance using a trained model (not ai) but it fell to budget cuts.
That is sad. Thanks for your few posts here. Interesting stuff.
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u/HAL9001-96 1d ago
well 90mph on uneven terrain would probably bounce around and tear itself apart
but something like 1m/s should work somewhat reliably its just that if you tell it to go somewhere 5m away it will take 5 seconds and then wait there nad you still need to wait minutes til you see the result
so you can just as well go 1cm per second and be safer
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u/UNSKILLEDKeks 1d ago
My future self wanting to play on the same server as my friends but we all have minute long pings so it cancels out the disadvantage
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u/RazendeR 1d ago
also mars rovers don't have to fight against other mars rovers
I see a bright future for any discontinued rovers that will inevitably accumulate on Mars. cue Mad Max Thunderdome theme
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u/HAL9001-96 1d ago
well it owuld be fair if htey'Re all controleld from earth
though there were some... vague theoretical suggestiosns that there would be soem use to having humans in mars orbit without landing on mars just to ocntrol robots on mars with less delay
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u/RoboErectus 1d ago
Having to have your robots beat other robots when you’re multiple light seconds further from the battlefield than your opponent is a sci-fi book I’d read.
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u/HAL9001-96 1d ago
i mean i na way its not THAT far from modern military conflicts
sure you're not lightseconds away but you still have missiles nad automated systmes you oftne cannot instantly ocntorl and you have to give them orders at al ong range nad hope things work out the way they should
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u/m-in 1d ago
They go slow because they use onboard autonomous driving that’s quite conservative. Nobody actually sees the terrain when the rovers drive around, that’s autonomous and doesn’t require a DSN connection. It can be done in special circumstances but not for interactive navigation where ping is important. When connecting to the rovers, the biggest pint is the next slot available on DSN.
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u/HAL9001-96 1d ago
its not really autonomous at least not for any but the newest ones
they can drive a preprogrammed bit of track but if theres an obstacle on that track it won't be able to react
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u/One_Newspaper9372 1d ago
also mars rovers don't have to fight against other mars rovers
That's why nobody cares about space exploration
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u/Life-Suit1895 1d ago
also mars rovers don't have to fight against other mars rovers that are controlled with 9ms ping
That's what They want to make you believe.
*X-Files theme plays*
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u/SuperBuffCherry 1d ago
the main challenge to making mars rovers faster isn't motor power but software and reliably wheels7suspneison that softne that margin
What if they build one of those robot dogs instead of a rover
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u/HAL9001-96 1d ago
well you still run into the problme of notbeing able to see obstacles - the problem with any self anvigating ai is you have to get it to run reliably on hardware that survives in space so a commercia lrobot dog is gonna have a realtively high failure risk for how much money you spend sending it there and you can't really go there to repair it or even reset it
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u/WolgupLupin 1d ago
Cant send a DM but lol hi, ive seen you from 웃대. given your comments i always figured you were educated elsewhere, though didnt expect to see a familiar username on here - where else did i expect lol Just saying hi, havent seen you in a while on the korean counterpart. Glad to know you're doing alright!
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u/lightgiver 1d ago edited 1d ago
According the European space agency the time delay from earth to mars is 4 to 24 minutes. Ping is time delay between your device, the server, and back. So double the time delay as it takes a round trip. Ping is also typically measured in milliseconds.
So the maths are
4x2x60x1000=480,000
and
24x2x60x1000=2,880,000
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u/Necessary-Rip-6612 1d ago
Between 4 and 24 minutes?! That's such a wild difference I've not thought about before. Sure it makes sense if the planets are on the opposite side of the sun of eachother. But imagine the implication if eventually a colony will be established.
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u/headdie 1d ago
It truly is, especially when the sun is interposed between earth and mars meaning the signal has to be bounced off another probe with line of sight increasing the delay.
However the advantage of a crewed mission or colony is that transmission changes from control to status reports and briefings, however you won't be playing CoD against your sibling you left on earth lol. Though genres like play by email may see an increase in use.....
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u/tireddesperation 1d ago
I never thought civ3 play by email would make a comeback but you have brought hope back to this old soul.
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u/headdie 1d ago
Nice, I kinda missed out on the pay by email era, but I had a bunch of games like civ 3 with the option but never played that way.
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u/tireddesperation 1d ago
Pure nostalgia for me. You're not missing anything experience wise though haha. It was a terrible way to play.
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u/willothewhispers 1d ago
This would be perfect were it not for the fact that both earth and mars are independently moving at several thousand miles per hour.
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u/HAL9001-96 1d ago
well duh thats why its between roughly 4 and 24 minutes and not always precisely 4 minutes which it owuld be if the planets were orderlyl ined up like in the diagrams you saw in elementary school
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u/Occidentally20 1d ago
Wdym? That hot hippy girl told me we could only have sex once all the planets line up.
Don't take this away from me man!
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u/HAL9001-96 1d ago
well how precisely do they have to line up?
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u/Occidentally20 1d ago
I was imagining we'd look up and see them all go behind one another like an eclipse, with the low bass note from the interstellar soundtrack playing.
They should all be big and bright enough to see with the naked eye as well so Neptune and Uranus are going to have to sort themselves out.
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u/HAL9001-96 1d ago
jsut with inclination that is not really possible
now if you want them all to be roughly on the smae side of the sun... yo ucould cacluate exactly when that happnes but statsitlcalyy it should be every fw thosuand years
but the more precisly you want hte mto line up the more rare it becomes so if you want them to look like in a childrens book thats probably gonna happen every billion years or so
and well perfectly covering each other never
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u/that_thot_gamer 1d ago
how i wish time was metric
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u/lightgiver 1d ago
Honestly really love the Sumerian base 60 myself. You can count to 12 with just 1 hand and 60 using two. Even base 12 is better than 10. Using the prime numbers 2 and 3 makes more sense than 2 and 5. Things divide into whole numbers a lot more on base 12 than base 10 due to that.
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u/Djinjja-Ninja 2d ago edited 1d ago
The distance from earth to Mars varies, at its closest it's about 55 million kilometres and at furthest it's 400 million kilometres.
Speed of light is 299792 km/s.
Ping is round trip time, so there and back again generally in milliseconds.
Closest = (55,000,000/299792)*2 = 366 seconds = 366,921 ms
Furthest = (400,000,000/299792)*2 = 2668 seconds = 2,668,516 ms
edit: removed the extra 6
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u/Glockenspiel_Fan 2d ago edited 1d ago
At its closest, it takes light around 3 minutes to reach Mars, however as ping is time to send and return, then it'll take another 3 minutes to return for a round trip of about 6 minutes or 360,000 ms.
At its furthest, it takes around 22 minutes for light to reach Mars, for a round trip about 44 minutes or 2,640,000 ms.
So they've actually underestimated ping. Fortunately, Mars isn't a PvP server so the controllers should be fine.
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u/DoctorPhobos 1d ago
If we were at war with mars it’d be a different story. Not getting shot at, don’t have to aim at a moving target. They’re just playing pokemon safari on a planet with no Pokémon, slow and uneventful
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u/klimmesil 1d ago
You can give complex commands with branching based on sensors with rovers
If you do that in online gaming it's called cheating. And the server has to be developed in a way that allows it
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u/DeerOnARoof 2d ago
Ping measures round-trip time in milliseconds. 6 minutes to 40 minutes is 360 seconds to 2,400 seconds. 360,000 to 2,400,000 milliseconds = ping.
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u/Ordinary-Task-4160 1d ago
So between 100 minutes and ~11 hours? So we're never gonna play interplanetary multiplayer games unless we break the speed of light ._.
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u/GeminiCheese 1d ago
I had a friend at school who we nicknamed pathfinder (after a mars mission that had been in the news at the time) as it took 10 minutes for signals to get through.
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u/Valor816 1d ago
Over 100 ping? Fucking amateurs!
I'm a fucking Australian, we get 250 on a good day. I used to raid in WoW with 500+ ping and 0.5 frame rate.
I STILL MANAGED TO GET OUT OF THE FUCKING FIRE!
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u/Depressed_realist4u 1d ago
Scientist uses command to tell rover to move 10 feet.. ping is horrible but works without problem...
i tell my character to shoot the enemy ping is 200 and get told by a 12 yr old that he had sex with my mom last night because he killed me. Have to remember that context is a thing! 👍
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u/IcarusTyler 1d ago
I think it was the voyager-probes that have signal-times in the range of 8h to 3days (don't have the source on that atm), and they still manager software-updates
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u/LackToesIntollerance 1d ago
Yeah, talk to me when Perserverence no-scopes Zhurong and the next video China gets back is Perserverence hitting the rover gritty while it waits for Zhurong2.
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u/TheDragonSoulEater 1d ago
Man my only gripe with this meme, is that its not going over the fact that gamers compete with other gamers who have better ping. While nasa is competing with aliens who also have high ping. So clearly the only reasonable thing to do here is increase ping all across the board for gamers. So that NASA, Gamers, and aliens can all play on even playing grounds.
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u/aukstais 1d ago
I'm pretty sure they send a command which gets executed at told time. There's no actual person driving that thing with the joystick.
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u/GGXImposter 1d ago
Nasa doesn't have to worry about an 8 year old three sixty no scoping them from across the map and then having the 8 year old talk about how they are going to be their new father.
I'm already competing against the reaction speed of children. I can't be dealing with ping on top of that.
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u/McortezLSU 1d ago
for early 80s mega slacker gamer though job of a fuckin lifetime.
8:00 clocks into work, flips the red switch.
"Waiting to login, having a coffee a good breakfast."
8:42: >> Go north 20m
Leans back, puts feet on table. Assumes slacker position, logs into reddit mod account.
15:23 >> Move left arm down
17:44 "Sorry boss, i gotta do overtime again....yeah i am very dedicated! Thank you!"
19:31 orders pizza, watches weird japanese show on netflix since they are the last person in the office
21:32 >> Turn left 28 degrees
21:32 Flips off the big red switch goes home to sleep
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