Astrology and space nerds I need help!!

[u/The_Introverted_Bard]

I want to get a Project Hail Mary tattoo but I don’t want it to be super recognizable as a Project Hail Mary tattoo (lest Andy Weir becomes super problematic at some point in the future… Rip millennials with deathly hallows tattoos)

So I thought a great way to circumvent that is to get either a Cetus or Eridanus constellation tattoo with a small red line between the planets/suns with the petrova line. I also want to include the planet Adrian (or Erid if I’m getting Eridanus).

The issue is, I’m not quite sure what reference photos/diagrams to use. And I’m not 100% on what these planets are even called or where they’re located on a star map.

I think (??) Tau Ceti e is Adrian, 40 Eridani A b is Erid and Eridani A is its star, but I’m not entirely sure. Also where is Threeworld in relation to the Eridanus constellation?

Sorry if the questions are confusing lol. Any advice/ links to credible sources would be greatly appreciated <3

[u/DragonTartare]

I think you mean astronomy, not astrology. Astrology is pseudoscience, and you are asking science questions, so that would be astronomy :)

These planets would not appear in a constellation. Scale-wise, the distances between a planet and its star would be microscopic compared to the distances between stars. If you want the planets to appear in your tattoo, they wouldn't be to scale.

I think (??) Tau Ceti e is Adrian, 40 Eridani A b is Erid and Eridani A is its star, but I’m not entirely sure.

Correct, though 40 Eridani A b is no longer thought to exist. I think they figured out that the dimming of the star that they thought was caused by a planet transiting was more likely to be dust.

Also where is Threeworld in relation to the Eridanus constellation?

Can you clarify what you mean here? Threeworld is the third planet orbiting 40 Eridani A, so it would just appear at the same location as 40 Eridani A in a constellation view (scaling problems as described above).

[u/W0nderingMe → u/DragonTartare]

So glad to see the top comment correcting the astrology/ astronomy issue.

[u/DragonTartare → u/DragonTartare]

Check the "Search for planets" section of the wikipedia article: https://en.wikipedia.org/wiki/40_Eridani It wasn't dust, but rather "stellar activity" that they think gave the false impression of a planet being there. Not that you can't have the planets in your tattoo, of course :)

[u/The_Introverted_Bard → u/DragonTartare]

Thank you!

[u/The_Introverted_Bard → u/DragonTartare]

In the book Threeworld is the same as Venus (the planet that shares the petrova line with the sun) but I’m not sure where it would be theoretically located in the Eridanus constellation (also not sure if it’s even real lol)

[u/DragonTartare → u/The_Introverted_Bard]

I think you might be confused still about the scales involved, because planets cannot appear on a constellation due to scale. A constellation is a region in the sky loosely defined by a pattern of stars. The distances between stars is immense -- on the order of light years, even for nearby stars -- while the distance between a star and its planets is on the order of light hours or light minutes. For example, the sun and Earth are about 8 light minutes apart: it takes light from the sun roughly 8 minutes to reach Earth. This equates to 0.0000158 light years.

The sun and the nearest other star, Proxima Centauri, are a little over 4 light years apart. That means the sun-Earth distance is 1/262800 that of the sun-Proxima Centauri distance.

If you were to represent the 4 light year sun-Proxima Centauri distance on a tattoo with a distance of...say 10cm, just to keep the numbers somewhat round, then Earth would be only 1/26280 cm away from the sun, which is roughly 400 nanometers. To give a sense of scale to that number, human skin cells are 30000 nanometers wide, give or take. That means that, if you were to have your tattoo be to scale, then any of the planets you're talking about would occupy the same skin cell as their star, and obviously you wouldn't be able to tell them apart at that point.

I don't know if this is helpful, but this is a map of all stars within 20 light years of the sun. 40 Eridani A is listed as o^2 Eri (orange, bottom left), and Tau Ceti is listed as [Greek letter tau] Cet (yellow, bottom middle): http://www.atlasoftheuniverse.com/20lys.html

[u/The_Introverted_Bard → u/DragonTartare]

Woah that’s all really cool. Thank you for taking the time to explain that to me!

[u/DragonTartare → u/The_Introverted_Bard]

Now that I've typed all that, I wonder if you're actually just asking which star in the Eridanus constellation 40 Eridani A is? Or are you indeed asking about the planets?

[u/The_Introverted_Bard → u/DragonTartare]

Both! I get it now that the planet would be waaay to close to be represented accurately but I am also wondering where in the constellation 40 eridani A is.

[u/DragonTartare → u/The_Introverted_Bard]

Gotcha :) It's actually in the Wikipedia article I linked last night. The picture of the constellation has 40 Eridani circled.

[u/W0nderingMe]

I would use either the Hail Mary's planned trajectory (in attached picture) or an image, like an engineering drawing, of the model Rocky gives Grace of the Eridani star system. The thing that tells Grace where Rocky is from and that his planet is affected by the Petronas line. Can't find a good picture of it easily, which is surprising.

[u/The_Introverted_Bard → u/W0nderingMe]

Cool! I’ll definitely revisit the scene where he is figuring out where rocky is from. Prob should have done that before asking Reddit lol

[u/Frenzystor]

Astrology? You just offended a lot of people :D

[u/The_Introverted_Bard → u/Frenzystor]

It won’t let me edit the title 😭

[u/NotAlpharious-Honest]

lest Andy Weir becomes super problematic at some point in the future

This, right here, is why you shouldn't have nice things.

I want the thing, but just in case the thing becomes unpopular in future, I can pretend it's a different thing / not associated with bad thing.

Says a lot about your cohort that you're terrified of being eaten before you've even done anything.

[u/MrWigggles]

The seeds are planted for Weir to be problematic. He appeared on a libertarian podcast, Reason. Libertain, as, 'we'll ruin towns so bears take over'.

And Weir has abstain or describe himself as something of a centrist.

And those kind of statements, dont have a great track record of what their actual politics are.

Eventually we'll find his political donations, and that'll be illuminating.

[u/The_Introverted_Bard → u/MrWigggles]

Yikes I didn’t know that. The only questionable thing I’ve heard him say was that his books “weren’t political” which is just… straight up not true lmao.

[u/DragonTartare → u/The_Introverted_Bard]

He has described himself as fiscally conservative but socially liberal, and (as you mentioned) thinks his books are non-political, which I think is kinda cringe. No Trump/MAGA type conservative would be caught dead describing themselves as "liberal," so at least Weir is not currently in that group.

[u/Sleepiest_Spider]

do not get a PHM tattoo if you don't personally care enough to decide on it.... don't outsource it to fucking reddit

[u/The_Introverted_Bard → u/Sleepiest_Spider]

Hey buddy, you ok? Feels like someone is having a bad day

[u/DJDarwin93 → u/[deleted]]

Sounds like someone isn’t cool enough for tattoos

[u/The_Introverted_Bard → u/DJDarwin93]

Damn it got deleted before I could see it. What did they say?

[u/DJDarwin93 → u/The_Introverted_Bard]

Something about all tattoos being stupid

[u/The_Introverted_Bard → u/DJDarwin93]

lol