Project Hail Mary – Stellar Navigation Chart

(valhovey.github.io)

126 points | by speleo 1 hour ago

13 comments

  • ggreer 48 minutes ago
    Just FYI the sizes of the planets, stars, and their orbits are not to scale at all. To get an idea of how empty space is, there are 63,360 inches in a mile, and 63,239 astronomical units in a light-year. So if you scaled everything down such that Earth was 1 inch from the Sun, Neptune would be 30 inches away and Alpha Centauri would be 4 miles away.

    If you were using a 4k display and had the Sun and Alpha Centauri visible at opposite sides of the display, the orbit of Neptune would be in the same pixel as the Sun.

    • hnuser123456 32 minutes ago
      Mercury is orbiting partially inside the Sun, and Jupiter is nearly as wide as the Sun when it should be 1/10 as much, so the planet nodes should be scaled down 10x relative to the Sun.

      Also, I did a top-down pixel measurement, where I could see the distance to Tau Ceti as well as the orbit of Neptune. The radius of Neptune's orbit was 32px, while the distance to Tau Ceti was 1152px, for a ratio of 36, when in reality, Tau Ceti is 11.9 ly away, while Neptune has an orbit radius of 30 AU, which means Tau Ceti is around 25,000 Neptune orbits away, so the planet orbit scale is too big (or distance to other stars too small) by a factor of ~694 (25000/36)

      Edit: Since this was top-down, the vertical displacement didn't factor into the distance, which also contributed to Tau Ceti appearing too close on screen, so the error is slightly better than that, maybe a factor of 600.

      Edit 2: Tau Ceti is rendered at 3.652 pc × 3 world units/pc = 10.956 world units

      Neptune’s orbit radius is rendered as 30.05 AU × 0.0065 world units/AU = 0.195325 world units

      The rendered ratio is 10.956 / 0.195325 = 56.09 Neptune-orbit radii

      The real ratio should be 25,067.5 Neptune-orbit radii

      The scale error = 25,067.5 / 56.09 = 446.9×

  • ge96 1 hour ago
    I am so happy this movie did great, the book was great

    Similar to me books: Bobiverse, Long Way To A Small Angry Planet

    I'm not a heavy reader

    This site is cool, I want to get to know stellar navigation stuff for astrophotography watching a video like this where they pull up star charts to point the telescope at it pretty cool https://www.youtube.com/live/TexqPMQMyZg?si=oEnvrxW21-D0VXGV...

    Tangent I'll throw in here, I never get the fabric folding gravity well diagrams as it seems to have a "down" direction, I guess it looks like it's down since it's a slice but the effect is an inward sphere?

    • imglorp 28 minutes ago
      > I guess it looks like it's down since it's a slice but the effect is an inward sphere?

      Yes, gravity is a vector field: every point in space near a heavy body has a vector pointed at the center of the body with a magnitude of the field strength. https://en.wikipedia.org/wiki/Gravitational_field

      Whenever someone uses fabric sheet analogy, they need to shout that the X-Y of the sheet is a 2 dimensional analog of X-Y-Z space, and the Z direction of the sheet is the field magnitude, with the slope indicating direction.

      All models are wrong, but some are useful (for understanding).

      • ge96 22 minutes ago
        Other thing is I believe they say gravity is strongest at the center of the sphere/core but I would think the mass is split evenly away from the core eg. maybe 2/3 radius from the center where it's equal mass on each side. But probably doesn't make sense wouldn't be a ball.
        • recursivecaveat 11 minutes ago
          Since the strength is represented by the slope of the sheet (not the depth), it should still line up. Underneath the ball at the very center the sheet will be level, to match as you say, that the field strength is 0 there. The exact shape will probably be wrong though since it's mostly determined by the shape of the bottom of the object.
    • godzillabrennus 9 minutes ago
      I doubt my opinion will be well-received by all, but I hope that creators like the author of the Bobiverse will be able to, affordably and within their own capabilities, create new forms of content, such as AI-generated long-form content, like entire TV seasons, as the technology matures. That series is fantastic.
    • stevenwoo 37 minutes ago
      Just a question - why do you classify Long Way with PHM - because there are aliens working with humans? I don’t see any other similarities. The technology IIRC (haven’t read in years) in the Becky Chambers book is closer to Star Trek than reality, and there’s not that much of an overarching plot - which is not to say a book cannot be good without one but it’s a big difference.
      • ge96 34 minutes ago
        True less technical and space themed so maybe not fitting just a fun easy read

        Oh yeah another series would be Nick Webb Constitution (Legacy Fleet), I think I got farther into that series but didn't finish it unlike Bobiverse, maybe I did finish this trilogy, I haven't read books in a while honestly. That was a good series though I remember the depiction of the space battles.

        Trying to be better at being in the moment vs. watching youtube/scrolling a website at the same time kind of thing

    • lstodd 39 minutes ago
      it's like an inverse gas bubble underwater, or a liquid blob in gas in microgravity, but without phase border.

      see, it's not that easy to explain or visualise.

  • rdtsc 59 minutes ago
    I can also recommend https://www.youtube.com/watch?v=8FT-oz9aZU4 Time Dilation Visualized (by The Overview Effekt).

    It talks about the distances and times involved and how time compression and astrophage infection rates work out. As a fan of the book and the movie it was nice to see the actual 3D star chart of everything. (warning: there may be spoilers there)

  • dkobia 1 hour ago
    Thank you for making this whoever you are. There is a wonderful video at https://www.youtube.com/watch?v=8FT-oz9aZU4 that visualizes space travel and time dilation in Hail Mary. What I wished I had immediately after watching it was an interactive stellar chart.
  • waynecochran 54 minutes ago
    Very cool. On Voyager 2 we placed a map on the side of the probe that places the position of our sun based on an array of Pulsar stars (the map was designed by Carl Sagan). I noted in the PHM movie Rocky and Dr Grace made similar 3D maps (I think they were pulsars(?)). I guess pulsars form natural beacons that can be detected at large distances.
    • twoodfin 1 minute ago
      Pulsars also have a rotational period that provides a reference point for interpreting arithmetic notation.
  • V__ 37 minutes ago
    "Thumbs" down
  • TeaVMFan 40 minutes ago
    For other software engineers thinking of following in Andy Weir's footsteps and writing a novel, I put together my guide to self-publishing using software tools and techniques here: https://frequal.com/forwriters/
  • Deprogrammer9 52 minutes ago
    Movie was awesome & will be watching again.
  • sigmar 1 hour ago
    this is cool. My nit pick- aren't the petrova lines curving along the wrong plane? For example, in our solar system the line should start at the sun and should be pointed at where Venus used to be, but then curve towards where Venus is now (until gets to venus). Since the astrophage will course-correct over their journey and stay in the same plane as Venus' orbit.
    • slg 36 minutes ago
      It has been a little while since I read the book, but I think you have the cause of the curve wrong. These things are moving at such a high percentage of the speed of light that there isn't much visible curve from the movement of the planet. The curve is instead caused by them leaving the star at the pole (which leads to a different nitpick of the visualization since the curve isn't shaped to represent that). It's theorized that the Astrophage do this to make is easier to find their way as exiting the plane of the solar system reduces the chances of there being any occultation blocking their view of their destination.
      • sigmar 15 minutes ago
        oooph, been a while and I don't remember any of those details. Good excuse for me to re-read it!
  • retrocryptid 39 minutes ago
    NICE!
  • Lapsa 23 minutes ago
    [dead]
  • nekusar 43 minutes ago
    It can be summed up as "Ken Meets Jesus", "Ken Goes to Space", "Ken is a bumbling moron", "Ken's first friend". "Ken's White Savior moment"

    This appears to be the norm for US based scifi now. Glad I'm watching movies like The Wandering Earth and Alienoid instead.

    It had a good premise. But it also fell apart immediately. Like, they only sent 3 people, 2 whom died on this UBER CRITICAL SAVE THE PLANET idea?

    And Ryan Gosling's character is a fucking moron. You're supposed to be a molecular biologist, and you're basically a reddit-gag line?

    Edit: lol -4 , like seriously, its a pretty bad show. I listed movies I compare it to. But no I get shit like "You must be fun at parties." Personal attacks, sigh.

    • Uncle_Brumpus 18 minutes ago
      Did Ken also get his catheter yanked out like in the book? I don't plan on watching the movie but that's the only thing I would even care a tiny bit if they included, because I just felt like it was such an odd highly specific bit and I want to know if they committed for the big screen.
    • ge96 17 minutes ago
      > The Wandering Earth

      That's a movie you watch while drinking, take a shot every time you see something absurd

    • tantalor 33 minutes ago
      > White Savior moment

      ???

      • cv5005 1 minute ago
        Chinese film having 100% chinese cast = good.

        American film having a single white male lead = not good.

      • rpmisms 28 minutes ago
        White people doing anything good is actually bad. Duh.

        /s, but I think I'm accurately describing the viewpoint you're responding to.

        • lazide 11 minutes ago
          It’s a description of a common Hollywood trope (or used to be), like the ‘magical negro’ [https://en.wikipedia.org/wiki/Magical_Negro].

          Hard not to see once you know about them, and they are indeed common.

          But what should replace it? Good Nuanced writing? Good luck with that!

    • TwoNineA 38 minutes ago
      You must be fun at parties.
    • lstodd 35 minutes ago
      As a european arthouse cinema snob I must say Gosling would have made a nice stand-in for Rocco Siffredi. Maybe.
    • Bud 24 minutes ago
      [dead]
  • makach 1 hour ago
    Elite Dangerous does it better. Pretty but idk.. get the AI generated feeling.