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Project Hail Mary – Stellar Navigation Chart

valhovey.github.io

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Re: Project Hail Mary – Stellar Navigation Chart

#221

Post by adolph »

rob74 wrote: post #204
speleo wrote: post #56

Hi there! This is Val, I made the star chart. There's a little "about" blurb you can open in a modal on the site, but I wanted to mention that this demo uses the amazing GAIA DR3 dataset from ESA. I have a Python script that renders all 1.8+ billion stars into custom images, which is what I used for the skybox. The star positions and colors all use the GAIA data (save for a few bright stars not in the set). The data…

Cool! One question: what do the planes represent? I thought it was the galactic plane and planes parallel to it, but then I saw that the "band" of the galaxy is (almost?) perpendicular to it, which doesn't fit somehow? EDIT: TIL that the ecliptic plane of the Solar System is at an 60.2° angle to the galactic plane ( https://en.wikipedia.org/wiki/Galactic_plane#/media/File:Mot... ) - until now I somehow assumed that t…

Thank you for posting this. I wonder if anyone has made a physical galactic orrery. It seems that the concept is used in the video game Warhammer.

Something implicit in the diagrams of the galactic plane but not explicitly stated is that the solar system travels clockwise (retrograde) around the galaxy [0]. I find this unexpected as I thought the same "right hand rules" of planetary motion [1] were somehow connected to those of electromagnetism [2] and would apply upwards in scale.

  The Sun follows the solar circle (eccentricity e
0. https://en.wikipedia.org/wiki/Local_standard_of_rest

1. https://en.wikipedia.org/wiki/Poles_of_astronomical_bodies

2. https://www.arborsci.com/blogs/cool/three-right-hand-rules-o...

Re: Project Hail Mary – Stellar Navigation Chart

#222

Post by waynecochran »

hgoel wrote: post #169
waynecochran wrote: post #7

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.

I thought the maps they made were of the neighborhood of stars around Tau Ceti, marking their respective home stars with the petrova line.

I believe you are correct. Way too close to use pulsars…

Re: Project Hail Mary – Stellar Navigation Chart

#223

Post by narag »

noir_lord wrote: post #212
p-e-w wrote: post #192

Earlier quoted context omitted.

It just boggles the mind how you can simply write a 3D program with a ready-made library today, instantiate tens of thousands of objects in 3D space, and the whole thing will render in real time on a phone without you ever having to worry about how that incredible performance is possible. The power of computers comes at least partly from the fact that for many practical problems, they let you effectively pretend that…

It does, it helps to stop and smell the roses occasionally and remember how far we’ve come. My first proper computer (defined by programming on it) was a 3.5MHz single core processor with 48KB of RAM. My current one is 16C/32T that can boost to 5.7GHz and has 64GB of RAM. Considerably more than a million times the RAM and about a million times the processing power (if you factor clock speeds, core count, OOE, branch…

My pet realization: most of the power increase has been spent on graphics at an ever growing resolution, including in resolution not only the number of pixels, that's a squared number, but also color depth and FPS.

Dealing with graphics has shadowed how hugely powerful the modern computers are. We're noticing now because of AI.

Re: Project Hail Mary – Stellar Navigation Chart

#224

Post by narag »

adolph wrote: post #221
rob74 wrote: post #204

Earlier quoted context omitted.

Cool! One question: what do the planes represent? I thought it was the galactic plane and planes parallel to it, but then I saw that the "band" of the galaxy is (almost?) perpendicular to it, which doesn't fit somehow? EDIT: TIL that the ecliptic plane of the Solar System is at an 60.2° angle to the galactic plane ( https://en.wikipedia.org/wiki/Galactic_plane#/media/File:Mot... ) - until now I somehow assumed that t…

Thank you for posting this. I wonder if anyone has made a physical galactic orrery. It seems that the concept is used in the video game Warhammer. Something implicit in the diagrams of the galactic plane but not explicitly stated is that the solar system travels clockwise (retrograde) around the galaxy [0]. I find this unexpected as I thought the same "right hand rules" of planetary motion [1] were somehow connected…

I wonder if anyone has made a physical galactic orrery.

Maybe it's harder than it seems. Does a definite galactic plane even exist? The ecliptic is defined by Earth's orbit, not a mean of all the planets. IIRC Sun's rotation plane is not aligned, not should it matter.

If there's a way to measure galactic plane, independently of Sun's orbit around the galaxy center (that also seems difficult to determine) it would involve measuring positions and trajectories of many very distant objects.

Re: Project Hail Mary – Stellar Navigation Chart

#225

Post by dwheeler »

speleo wrote: post #168
dwheeler wrote: post #145

Those interested in this might also like my "Project Hail Mary Stellar Map" at: https://dwheeler.com/essays/project-hail-mary-map.html My page shows a stellar map (from the viewpoint of Polaris) and a sky chart showing the key stars from Earth's viewpoint. Source code (MIT license for my stuff) is at: https://github.com/david-a-wheeler/plot-stars

Thank you so much for the blog post! I credited you in the about page, I used your charts as reference for the Astrophage infection graph view with the Petrova mode. I shared your blog with my friends, it was a great read.

Thanks for the credit, I appreciate it! Glad it was helpful.

I wouldn't call it a "blog post" though, it's simply an essay. I update my essay whenever I decide it needs updating, and "blog posts" are usually chronological and fixed in time once posted.

Take care!

Re: Project Hail Mary – Stellar Navigation Chart

#227

Post by dylan604 »

joemi wrote: post #191
dylan604 wrote: post #100

Earlier quoted context omitted.

Are you comparing game bindings to vim bindings? Isn't that an apples/oranges thing?

Considering we're not discussing a game, it seems like a perfectly valid comparison.

"if you're into Unreal Engine key bindings." :shrug:

Re: Project Hail Mary – Stellar Navigation Chart

#228

Post by adolph »

narag wrote: post #224
adolph wrote: post #221

Earlier quoted context omitted.

Thank you for posting this. I wonder if anyone has made a physical galactic orrery. It seems that the concept is used in the video game Warhammer. Something implicit in the diagrams of the galactic plane but not explicitly stated is that the solar system travels clockwise (retrograde) around the galaxy [0]. I find this unexpected as I thought the same "right hand rules" of planetary motion [1] were somehow connected…

I wonder if anyone has made a physical galactic orrery. Maybe it's harder than it seems. Does a definite galactic plane even exist? The ecliptic is defined by Earth's orbit, not a mean of all the planets. IIRC Sun's rotation plane is not aligned, not should it matter. If there's a way to measure galactic plane, independently of Sun's orbit around the galaxy center (that also seems difficult to determine) it would inv…

Yes, an example is "Local stellar kinematics from Hipparcos data" [0]. Afaict: stars have color (red or blue shift) which represents relative motion; Hipparcos is a large large dataset from an eponymous satellite; fancy math determines relative motion based on position and inferred distance.

0. https://arxiv.org/abs/astro-ph/9710077

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