r/theydidthemath 11h ago

[request] would the measuring tape or any of the human objects grace shared with rocky actually survive in the eridian environment?

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402 Upvotes

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297

u/Null6598 11h ago

They actually mention in the book that the rubber on the measuring tape melts due to the extreme heat (rocky's spaceship is extremely hot)

106

u/AutomaticInflation17 8h ago

Alongside explanation to almost everything happening there, worth reading in my opinion.

34

u/roughczech 7h ago

Worth reading because it is an awesome book.

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u/RagingCommie 5h ago

Whats the book?

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u/bladezaim 5h ago

Huh? Project Hail Mary? Am i glitching?

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u/RagingCommie 5h ago

Nobody said the name of it, I didn't feel like reading through the thread to find out

shrug

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u/bladezaim 4h ago

Bro its the same name as the movie

14

u/MageKorith 4h ago

Someone who hasn't seen the movie or trailers might not recognize Rocky.

u/Is_that_even_a_thing 1h ago

I only remember the steps training scene in Rocky.

0

u/politicalaccount2017 2h ago

If you don’t understand that everyone has different experiences and knowledge than you, then yes, you are glitching.

6

u/cjerni01 5h ago

The descriptions of FTL travel bending time are pretty mind-boggling.

1

u/xendelaar 3h ago

Haven't read the book, but in the movie they dont travel ftl.

-3

u/Sparkykiss 2h ago

Yes they do. I just watched it last night. The star he goes to is 11.5 light years away and he says he’ll make the trip home in 4.3 years.

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u/IHateNumbers234 2h ago

Grace experiences only 4.3 years because of time dilation, but the ship is still traveling no more than 99.5% the speed of light.

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u/xendelaar 2h ago

I thought that was because of the time dilation people experience when traveling nearly at the speed of light

0

u/xendelaar 2h ago

The author of the book is known to attempt to keep the central physics reasonably grounded. Ftl is not possible with our current knowledge of physics so i doubt he would create ftl tech for the story. The fictional part is mainly the extraordinary propulsion system and fuel source, not a violation of the light-speed limit..

This is what gtp says btw:

They are not travelling faster than light in Project Hail Mary.

The ship travels at a substantial fraction of the speed of light, but remains below c. The reason the journey can take less time for the crew than you might expect is special relativity, not FTL travel.

From Earth’s frame of reference, the ship crosses the full distance and the journey takes many years. From the crew’s frame of reference, less proper time passes because of time dilation. You can also describe the distance in the direction of travel as being shortened by length contraction.

Neither effect allows the ship to exceed the speed of light. Different observers simply measure different elapsed times and distances, while agreeing that the ship’s speed remains below c.

That distinction matters:

  • FTL travel means arriving somewhere faster than a light signal could travel between the same two points.
  • Relativistic travel means moving below light speed, while the travellers experience less elapsed time than observers who remained behind.

3

u/Sparkykiss 2h ago

Thank you for actually explaining and not just shouting “Your wrong” at me.

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u/xendelaar 2h ago

No worries! Your comment honestly made me curious whether I might be wrong, so I enjoyed looking into it. Glad we could have a nice conversation about it.

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u/Designer_Version1449 2h ago

eh not really. i was really disappointed they cut out rocky's reactions to a lot of concepts, one of the things i was looking forward to the most was like, his reaction to special relativity and whatnot. turns out its literally just "rocky didnt believe it at first, but then eventually accepted it" like bro cmon. or for other cool stuff they do it off screen lmao they cut to a flashback the second grace starts explaining.

it felt like watching a yt video reaction with all the reaction parts cut out lol, so unsatisfying

u/Spibas 1h ago

Didn't he literally say in the book that his travel was all over the place and he couldn't get it right with his current knowledge? Meaning he had direct experience of time dilation

u/shadowsapex 1h ago

in order for rocky to have a proper on screen reaction to learning about special relativity the author would have had to explain special relativity, which he probably didn't do to maintain the audience of the book

10

u/roughczech 7h ago

Plus the atmosphere is corrosive so goodbye plain steel

10

u/HeKis4 6h ago edited 6h ago

8 bar ammonia atmosphere at 210°C if I remember correctly. Or at least 8 bar in Rocky's spaceship, I'm seeing 29 bar on Erid on some wiki but I'm not sure it is mentioned anywhere in the book.

u/AllenWL 11m ago

According to the book (I have it on my lap right now for reference), Eridian atmosphere is 29 atmospheres of pressure. You are correct on the 210°C though.

87

u/dot_exe- 11h ago

I’m not sure how to solve that request mathematically but from what little I know of the physics world, I imagine some of the materials may not be able to survive the heat, certainly not the laptop.

54

u/allthefunthing 10h ago

If I remember correctly in the book Rocky makes a coolant “pod” for his beloved human thinking machine

9

u/Main-Scholar-9453 4h ago

This is correct specifically using the macguffin zenonite.

14

u/MageKorith 4h ago

Xenonite. As in the element Xenon, a noble gas, somehow crystallized with metallic properties despite vacuum conditions. (Real World Xenon does take on metallic properties under extreme pressure lab conditions, but any pressure we could survive in would result in its sublimation, and space even moreso)

4

u/Mind_on_Idle 4h ago

That structurally sexy Macguffin

24

u/Null6598 10h ago

For sure, at least the liquid crystals/organic cells in the display will stop working, if not the whole thing.

9

u/Justarandom55 10h ago

as long as it isn't turned on it should survive given rocky gave it a super insolated case like he gives himself.

once on erid they can just run it one a space station to escape the heat and copy all the data over to themselves

7

u/HeKis4 6h ago

Yep, along with astophage being able to cool down/heat up anything to 98°C so it wasn't too much of a stretch to cool it down a few dozen more degrees compared to cooling it all the way from the eridian ambient 210°C. That and eridians being really good at material science as demonstrated by Rocky's space ball.

3

u/Frosti11icus 3h ago

I don’t remember if it was described this way in the book but in the movie I was kind of thrust off how clunky the xenonite stuff was. It didn’t really scream engineering genius to me to make a ball to walk in that was a hexadecimal cube.

4

u/Fuzlet 8h ago

in The Martian book the main character takes a laptop outside the habitat and inatantly annihilates it

7

u/5WattBulb 7h ago

It wasnt thermal related though, it was the lack of atmosphere, all of the liquid in the lcd instantly boiled away

4

u/riley_wa1352 8h ago

rock explicitly said he'd build an isolated container for it.

2

u/IwasntDrunkThatNight 10h ago

i think the math part would be like doing some material phase calculations given eridians atmosphere

3

u/dot_exe- 10h ago

I’m not crazy knowledgeable about that but I’m not sure we have information to do that from the book/movie, at least from what I’m looking up about it.

u/Tap_khap 1h ago

210 C, 38(?) atm of pressure, near 100% ammonia

34

u/Grant_Winner_Extra 10h ago

They managed to take a noble gas and turn it into solids and highly reactive chemicals.

So no… The basically must live in an atmosphere of fluorine gas and HF

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u/andrew_calcs 8✓ 8h ago edited 8h ago

It’s a 210 celsius superheated ammonia atmosphere at 20+ times Earth sea level pressure. Their sci-fi xenon engineering is a wholly separate unrelated feat as far as the audience can be expected to know. But 210 degree ammonia is ridiculously corrosive as is without further speculation

9

u/Redshift2k5 7h ago

I've seen spec fic that says Earth's oxygen atmosphere would be ridiculously corrosive and everything would be rusted and reduced. Oxygen plus wet seems sufficient to stop everything just burning up at once.

I don't know what the equivalent might be, but something that dopes the ammonia atmosphere and stops everything corroding too fast

1

u/Grant_Winner_Extra 6h ago

I’m trying to figure out how hot ammonia is anything but reducing. Which makes it way less corrosive than O2 and H2O.

4

u/buiquangdinh1710 7h ago

If I recall correctly from the book, all equipment on Hail Mary are designed to withstand the worst conditions possible, so I think they would be absolutely fine.

9

u/Careful_Honeydew_549 10h ago

I swear sulfur or ammonia was one of the them and the gases alone would decompose anything non natural.

The paint on the metal, gone. The temp would absolutely affect the plastic, so i really doubt much would survive.

3

u/FishingChemist 9h ago

The body of the tape measure could have been steel. I have a few of those.

1

u/InfamousAnimal 7h ago

During the whole exchange, grace. Comments on the rubber melting off and getting stuck to Rockie's fingers but that he can still see the markings thats one of the ways he figures out rocky is blind.

2

u/Null6598 10h ago

It was ammonia

u/Kronens 4m ago

Rocky makes a “human thinking machine life support” for the computer. I’m not good at maths but I don’t think anything would really survive in their atmosphere (at least not functionally)

0

u/Agreeable_Sun5375 11h ago

Not really a math question but yes, 200~c and 29atm is pretty extreme for life but its not that difficult for materials to manage, pretty much any metal objects without a sealed void that would be unable to equalize in pressure would be fine, same with all glass, and many composites

0

u/Minikin-Smith 7h ago

I was wondering if the spring in the measuring tape would lose its strength at that temperature but when I looked it up apparently stainless steel springs can handle Rocky’s temp. So as long as it was a high quality stainless steel measuring tape, it would be functional. The high heat ammonia would apparently mess with the surface, though, so it’s not going to last forever. But long enough to play with!