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Moon

ciechanow.ski

3,128 pointstodsacerdoti250 comments

This is wonderful!!! Generalizing here but we really do take the moon for granted.

I bought a 'big ass telescope' a few years ago in an effort to bootstrap a hobby that I'd flirted with for decades but never really committed to. It's a Celestron 11" SCT and I really had no idea what I was getting into. When I think of space I think of things that are really small in the night sky, planets, galaxies, nebula...(turns out most of them aren't *that* small and I overshot the targets I had in mind)

I kept trying to photo galaxies and star clusters and all of these exotic things but had a bunch of trouble with tracking with long exposures. Out of frustration I ended up just pointing it at the boring ol' moon to at least get used to the equipment and workflows.

I fell in love with Luna.

The magnification of this scope really allowed me to explore the surface in a way I never had before. I got to know the 'map' and suddenly related to our celestial neighbor in a whole new way. It was also the very first image I was actually not embarrassed to share - https://imgur.com/a/t9b1Uug

I since then improved my knowledge and technical skill but the month of the moon at the end of 2021 was really pretty spectacular for me.

> turns out most of them aren't that small

I haven't realized Andromeda is 4x bigger than the Moon until I tried to take a picture of it

https://mikkolaine.blogspot.com/2014/01/size-of-deep-sky-obj... (not my picture)

That’s incredible. Illustrates how incomprehensibly big galaxies really are. There’s a thing 2.5 million light years away which still appears 4x bigger than the Moon.

Very much incomprehensible, not only for outer celestial objects since we most probably will never fully discover our own physical earth planet or human body, let alone our thinking brain and our elusive consciousness.

Andromedia the closest galaxy to Milky Way (MW) is estimated to have one trillion stars while MW itself is estimated to have 250 billions. God really knows how many of them really exist and who's counting anyway? It's a blind faith at its worst to pretend we know the numbers since it's most likely that the earth and its sun bound astronomers (including the farthest distance ever Voyager spacecraft) are several orders of magnitudes off the marks.

It's also estimated that's more than a trillion number of stars inside the two galaxies (Andromeda and MW), not number of planets, not even the number of moons (the very title of this HN post).

Overall it's also estimated that there's more than a trillion number of galaxies (not stars) inside our universe.

To make matter even more complicated, all of these celestial objects are moving in very high speed relative to each others and none is static. These galaxy are millions or billions light years away from earth and by the time their EM signals has reached earth, they probably have already dissappeared or morphed into something else.

How about non observable part of the universe?

How about other parallel universes that physicists claim to exist?

My personal conclusion to this mind boggling facts is that to assume and conclude there is only earth that has living creatures is very much premature and naive.

> just imagine if you could see all those galaxies and nebulae with your naked eye

I think I’d wind up buying the Vision Pro if it can realistically portray seeing the world in a wider spectrum than our eyes can. I don’t want cartoonish images of objects pasted into the sky. I want to see what I would perceive if we e.g. gene therapied a few extra cones into our eyes to see more of the EM spectrum.

Oh boy if you're willing to spend money to look at the night sky - but feel like AR falls short currently - I highly recommend looking into NODs, something like a PVS-14, you might be able to pick one up second hand for the price of a new vision pro. Unfortunately photomultiplier are still quite expensive even if they are only gen2 :( some really cool tech though.

Hmm, spending that much on seeing the stars vs. augmented reality... I might lean toward the stars

Definitely not arguing with you! Though I have a soft spot for analog tech in this area. I think AR might still have a very bright future, especially if you're learning about the night sky. I've spent many hours scanning the sky with an app I found that had an AR feature that allows you to point your camera at the sky and get an overlay on everything (including sattelites!).

I’m interested in that app if you have a link.

It's called Star Walk 2 https://play.google.com/store/apps/details?id=com.vitotechno... Just a FYI that if you choose to purchase the app you will still have to purchase the "all in one bundle" inside the app, I believe it's ~$5 and it gives you the sattelites, extended solar system, deep space objects and more. There's also a free ad supported version that offers the same base catalogue.

Night vision goggles have made immense improvements in recent years. Although the new technology in night vision is also very expensive. If they ever become accessible to the average consumer, they will change the world profoundly. Because you can walk during night as if it was day.

For astronomy, they probably won't make a difference, but it shouldn't be impossible to make goggle technology that converts astronomically interesting wavelengths to the visible spectrum.

It's not the wavelengths that are the problem but the exposure times; even with our best sensors we still need long exposures to capture compelling images of galaxies and nebulae. I don't think it will ever be possible in real time.

that's not a problem with displaying that information.

the post you replied to is not wanting to see like Geordi LaForge from Star Trek: The Next Generation; in real time. they're (at least I think they are) wanting to visualize already captured information, such as x-ray and radio emissions overlaid a view of the night sky.

> ...I want to see what I would perceive if we e.g. gene therapied a few extra cones into our eyes to see more of the EM spectrum.

Maybe I misunderstood this part then?

For people thinking of getting into moon gazing try binoculars first!

Laying down on your back, plopping a nice pair on your eyes and just looking at the moon is a fantastic experience. Aside from much better UX, binoculars also have depth-perception which makes the visuals all that more engaging.

If you have really nice clear sky in your area you can easily do that with stars and some planets as well.

I was a kid living in Botswana when Halley passed earth.

We watched it every night through binoculars.

Marvelous clean air - humidity around 0%, just some dust. No light pollution (there wasn't an electricity grid in some 100km around, just a handful of small diesel aggregates).

The binoculars were more than enough to see the comet, its tail. And even get a feeling of the tail arcing in three dimensions.

If you got good bins try looking at Jupiter as well. Typically on a clear night you can see several of the moons.

I was able to take pictures of them with a DSLR with a decent zoom lens! I used Stellarium to check the positions, waited for a very clear night, and was able to get a very nice photograph of that and of the Pleiades.

This blew my mind a few years ago when I got some decent binoculars. Depending on their positions you can see all four of the Galilean moons - even from a vantage point in a major city.

I saw them entirely accidentally. I was looking at the moon through bins and checked out The Other Bright Thing nearby and was shocked to see what looks like little dots next to the big one. As Galileo himself would have done, I immediately went on the internet and consulted a sky chart, which confirmed that I was seeing the moons of Jupiter.

I still occasionally drag my friends out to look at the moons on a clear night. It's my favorite bit of practical astronomy to share.

Depth perception? I would think objects as far away as the moon shouldn’t produce a meaningful difference between the left and right eye. But that does tell your brain they are far away, so perhaps that’s what you mean.

It's not really depth perception, but there is a significant difference in how objects are perceived when looking with both eyes. It's also applicable to binocular splitters used with a single mirror/lens telescope.

Your brain can also do 1+1 and end up with 2.5 or even 3 in the brain :) I have really bad eye sight on both eyes, one can not see enough alone but both together see much better than I would expect on the same distance.

This is great advice! It's really amazing how much more you can see with a regular decent pair of binoculars. I treasure the memory of being able to see some of the star clusters that I could only vaguely make out with the naked eye for the first time, now I basically bring them every night walk :).

I think the problem is that I would like to have an image stabilized version of that. Even small ticks of you fingers amplify quickly into shaky images.

I think instead of an eyepiece (or in addition to one) most consumer telescopes should include a usb image sensor that can screw into where the eyepiece is.

A lot of binoculars have a mount for a tripod which I can definitely recommend trying out of you happen to have both, or at least consider if you are planning to pick up a new pair.

There are also image stabilized binoculars. I have an older Canon 10x30 that I absolutely love (enough to tolerate the plasticizer now breaking down on the rubberized exterior)

I have the same, about 10 yrs old and agree the image stabilization is awesome.

You can buy generic replacement electric eyepieces that fit

Some suggestions of mark/model of binoculars good for that? With a budget of 1000$ /€(I could stretch it a bit more if it's worth the extra money)

I have the Cannon 10x30 IS from a long time ago and they are the best binoculars I’d ever tried. I’m pretty shaky so the image stabilizing is game changing. I’m sure the more powerful pairs are incredible and in that case image stabilization is a must. https://www.usa.canon.com/shop/lenses/binoculars

Are binocular superior to monocular for that use case? I thought binocular were good for depth perception which I'd assume doesn't matter here?

Any specific binoculars you can recommend?

The most important is that they capture enough light, for which the lenses must have a large diameter. 50mm is typical. Magnification around 10x is good. This is referred to as 10x50. I have a Celestron Skymaster 15x70 myself, which is specifically for night sky observation. The 70mm is very good, but the weight and the magnification make it difficult to hold still without a tripod, though you can still use it without, e.g. lying on your back

Try a good monopod. They're significantly more portable and give just enough stability in most cases to give good views whille allowing less restricted movement than most tripods.

I have a set of Vortex Diamondback HD 10x50s that are pretty affordable and do a good job with the moon (and hunting near dawn and dusk). The optics are definitely better than I expected for the price.

It really is a great shot. I always daydream of showing today's technology to the great the great minds from centuries ago. Not sure why, but I do.

I’m sure it’s different for everyone but I think it would just be the unbridled enthusiasm and love for the subject that they would show, the tidal dopamine surge of all the mysteries that have been unlocked, the validation of all the mysteries that remain. It would be amazing.

I have the same fantasy. I think it’s appealing because I imagine they’d be able to appreciate all the amazing things behind it more than most people, dead or alive.

Me too. Sometimes in big concerts I can't help but think about what would the avg roman say if he would just appear here?

"Wow so many lights" is the first answer I can think about right away

And I'm here for it! :D

Similarly, I came to learn some selenography writing a "voxel" (well, ray-casting) web game ... where you shuttle about the moon from crater base to crater base.

I became kind of fascinated with the craters, names of the craters (and history of those names), the "dark-side" and all the wild topology there. (Although I think I have tiles for the entire Moon, you don't have the fuel to get there.

I really like that one, so sad that the framerate tanks after one or two flights. Tried all the settings on the debug menu but only reload helps as you stated in the documentation. Happens both in firefox, firefox developer without plugins and in chrome.

I remember playing another moon lander 35 years ago in school on the swedish computers "Compis". Was a very basic version but I still loved it, it's something with slow heavy objects where you need to plan ahead what, when and how much you need to do.

Did you publish it? Can we see?

I was curious too. GP's github is in their profile and it looks like this is what they were talking about:

https://github.com/EngineersNeedArt/Mooncraft2000

What a cute game, loved trying it out!

if y'all only care about the game: https://mooncraft2000.com/

If you're curious about the naming of the Lunar craters, the first full English translation of the Almagestum Novum is being worked on here:

https://www.amazon.com/dp/1739314565?ref_=pe_3052080_3975148...

Welcome to the hobby (even if a few years late). Pretty much everyone has the same experience as you. You buy the telescope, and then realize you need to buy a telescope for your telescope to use as a guide scope for accurate tracking for longer exposures.

However, those long exposures are much more likely to get photobombed by an airplane or satellite. So you're really better off taking shorter exposures with the highest ISO you can get away with, and then just stacking them.

I have a much wider scope that I can do 30s exposures unguided before trailing starts to become noticeable. If you can get away with 15s, you'd be amazed at what you can achieve with newer sensors.

Just some hints to help the disappointment at bay and maybe get you playing with the toys

An 11" SCT is a commitment to use. Do you have it on a permanent mount?

No, but i did just get a wedge so I could start tinkering with polar alignment.

I also bought a Seestar S50 last year and have been having an absolute blast with it. Feels like a renaissance in astronomy is upon us.

What a beautiful photo! You have a good eye.

I really like the way you caught the craters along the terminator, including the one at the bottom where you see sunlight on one rim and the rest is visible only because of Earthshine.

The Moon is such a great subject that you can also get some nice shots with just a camera and a telephoto lens. Here are a couple of mine.

Moon over Menlo: https://www.flickr.com/photos/geary/24118398766/

Moon, Mars, Venus: https://www.flickr.com/photos/geary/16598905865/

Thank you! You as well!

The shadows are very much my favorite part of this kind of shot. It provides so much visual texture to the surface, showing not only how rough it is but how smooth it is. the 'scar' to the bottom right (aka Alpine Valley https://en.wikipedia.org/wiki/Vallis_Alpes) is always one of my favorites.

Thanks again!

Is there an information resource to find local telescope owners who give access to the public for viewing?

(startup/app idea!)

Good God, no.

Pretty much every telescope owner will happily show you the sky - after you've made an effort finding out where they gather, or if you just happen to walk by. The instagrammification of astronomy, with hordes of influencers rolling by without concern for the subject matter, just to insert themselves everywhere, is too horrible to consider.

It's not hard to find. Type "<city> astronomical society" into your search box. They have public websites, horribly outdated. Reach out to them, join the group, and you're more than welcome. But may there never be "an app for that"

Just search for local star parties in your area. Although, be willing to bend the definition of local depending on how light polluted your area is. My local is 4 hours away. Also, some colleges have viewing nights available. Even in light polluted areas, you can still see things for public viewings. They just suck for anyone wanting to image.

There are tons of sites listing them, but I doubt there's an absolute exhaustive list as it's all self-reporting to each of the sites. Your app idea would just be another in a list of places, sort of like the xkcd app about yet another standard.

https://www.go-astronomy.com/star-parties.htm

https://skyandtelescope.org/astronomy-resources/annual-starg...

Here in the EU you can look for "dark sky parks" which are basically parks or areas in nature designated for night sky viewing because of the low amount of light pollution and they are great spots to meet people, I'm pretty sure you have these in the US as well. I advise bringing a red light if you have to do some walking. Another recommendation would be to see if you have any actual observatories near you, some of them have events for the public every now and then. The people in this community are some of the friendliest I ever met and love sharing their interest and enthusiasm.

Sometimes the most meaningful connections are with what’s been right in front of us all along

Can you see Saturn in good detail? I'm interested in picking up a telescope.

i have the 6" celestron sct, and on a clear night this is pretty much the amount of detail i can make out directly:

https://www.reddit.com/r/telescopes/comments/pmlbne/jupiter_...

i'm sure with tracking and stacking it would be much more.

Just to clarify is that the detail you can make out with the naked eye or a digital censor? If you meant digital censor, how much of a difference with the naked eye would you say it is? I've had this telescope on my list for some time but am not sure if my expectations are realistic.

Yeah, naked eye, although with a 6” telescope, I’d expect it to be a bit fainter - certainly that is the case through my 9.25” scope. I can often see a band in its rings.

It also depends a lot on atmospherics, if there is a lot of turbulence in the atmosphere it makes things less crisp (well, “dancey”, like looking through a heat haze.)

Look up your local astronomy group and go along one night, and see for yourself before buying anything. Saturn isn’t great at the moment (assuming London-ish latitudes) but Jupiter is around all night and you should be able to see it through a variety of scopes and eyepieces if you went along to a sky party.

Honestly, the first time I saw Saturn through a telescope I nearly cried. Truly amazing.

An SCT11 should have no problem making out the rings of Saturn and maybe a band or two. But it's not a good beginner scope. Long focal lengths are hard to manage if you don't know what you're doing

Why everyone is taking black and white pictures of the Moon? It's 2024!

Fantastic photo - you made me think about getting a telescope

It’s a lovely shot.

Bartosz has a patreon where you can sponsor these works, and on it he posts very detailed explainers of why and how he created each page.

The one for Moon is at https://www.patreon.com/posts/on-moon-118130286

Thanks for pointing this out. Bartosz absolutely deserves some paid support for his efforts.

Thank you for sharing! Big fan of Bartosz's articles and somehow didn't think of looking him up on other platforms

You don't have to, the link is at the end of the article :)

You guys are reading articles to the end?

To be fair on this one, most of the times I complain people haven't got to the end of some short story before asking. This is an enormous and dense resource. Great, but I started scrolling and got surprised.

100%, it is definitely a commitment but it is a really incredible blog. I wish I could find more like it! I saw the mechanical watch post the other day for the first time and was hooked.

Does this come with the page/code to store, or is there a good way of doing this? I looked a while back for properly archiving pages and their code but things were all in the works, maybe that's more solved now.

This kind of thing seems like a truly outstanding resource, and I'm happy to pay for it, with the desire to have this for when my kids get older.

Related: last Sunday (December 15th) was the *luna*stice - the northernmost endpoint of the moon's 18.6 year cycle during which the rise/set points move between north and south. On Sunday it was as far north as it gets, and for the next generation it will move slowly south and then back again.

This cycle has been known to some humans for more than 3000 years, and appears to have helped structure architecture/layout at various American locations such as Chaco Canyon (New Mexico) 1000 years ago. It takes a minimum of 3 generations to establish the cycle, which indicates something about the level of social and scientific organization in these societies.

As a big fan of both the Moon and ciechanow.ski this article is right up my alley.

During the 2024 solar eclipse I was explaining to people how an eclipse must occur during a new moon, and this article would have really helped. The discussion also made me realize how little most people spend thinking about the solar system and the relationship between the moon, sun, and earth. These things fascinate me (I think it's just the sheer scale of it all), and I hope to be able to get more people interested as well. The solar eclipse was great for that!

People are impressed if you can name the current moon phase and tell them what it'll be next. But it only takes a mental model of where the sun, earth, and moon orbits are relative to each other. I also find people are intrigued by the concept of earthshine, and often haven't noticed it until you point it out.

For a waxing moon the circular arc is on the right hand side and for a waning moon the circular arc is on the left hand side [Here in the Northern Hemisphere]. It would have been nice if the mnemonics Decreasing & Cresting worked but they don't. I personally use Developing & Collapsing to refer, respectively, to the waxing and waning moon. Has anyone a better couple of words than these?

In French we have "premier quartier" and "dernier quartier" for "first quarter" and "last quarter" respectively. The mnemonics work with lower case letters: p and d.

In English, the "d" for "decreasing" also works in lowercase, I guess that you can use "p" for "progressing".

Earthshine is such a cool phenomenon to point out

> People are impressed if you can name the current moon phase and tell them what it'll be next

I'm speechless

And once you internalize this, every image where there are moons pasted into the sky without understanding this will trigger you. It's like bad kerning. Once you see it, you can't unsee it.

> solar eclipse I was explaining to people how an eclipse must occur during a new moon

Hey, that's the first the time I realized this.

And a lunar eclipse only during full moon…. These constraints made it easier to predict eclipses in the past.

Similarly - as full moon must be opposite to the sun, full moon moonrise happens around sunset and moonset happens around sunrise.

Also full moon rises the highest in winter, contrary to the sun - when it’s at it’s lowest[1].

Funny things happen at the poles where sun is above/below horizon for half a year: https://astronomy.stackexchange.com/a/27750

[1] the further from equator you are the more pronounced it is.

The really satisfying thing for me was when I was on a sailing course and was instructed in how the moon causes the tides, and how the phase of the moon corresponds to springs and neaps.

Thinking about how the Moon, a body over 380,000 kilometers away, can perfectly block the Sun (something 400 times larger than itself) because of their relative distances is just mind-blowing for me

Really excellent. Since I live in a high rise I've marked the cardinal directions on the floor and walls and been trying to develop a spatial intuition for the ecliptic, essentially trying to be able to easily imagine myself tilted in the northern hemisphere subtropics rotating around a sphere rotating around the sun. End goal would be an automatic intuition of where to look for the Sun, Moon, and all the visible planets. This sounds insane typing it out but its very passive and genuinely satisfying. Not being on the equator and the natural tilt of the Earth are the two factors that make this most difficult, of course.

I get this. You’ve got me wondering how to get this project Wife Approved Status

My wife came with 9 telescopes in various states of disrepair.

That's okay; we don't kinkshame here.

Nerds often marry other nerds ;)

It's not insane in the least. I try to always make a point of observing the ecliptic when I travel, it creates a wonderful interconnectedness to places all over the planet. There are going to be some lovely conjunctions in the next few months that will provide a great opportunity to share this with people. It's actually pretty intuitive when there are 3 or 4 visible planets in a row once someone points it out.

I built an ecliptic pathfinder in the Black Desert in Egypt a few weeks ago. It's a piece of land art comprising three piles of rocks on the near horizon, each marking the position of sunrise (if you are stood in an approx 200 metre by 5 metre strip) for the summer solstice towards the north east, the spring and autumn equinoxes to the east and the winter solstice towards the south east.

That is fantastic.

Check out the North Paw Directional Anklet. It’s basically a compass that vibrates whenever you face magnetic north. From what I’ve read people seem to develop a sense of direction pretty quickly.

The one they gave me seems to vibrate when I face any direction but only when I leave the house.

You'll be sad to find out the company went out of business a long time ago

Ciechanowski is likely the best content producer of our time, absolutely fascinating reads. Imagine having such a person as a teacher - he could probably excite students about any scientific topic.

I'd love to spend my time working on such articles when I'm retired :)

This isn’t an exaggeration ! We get but one or two of his articles per year but they always delight the kids and big kids too.

No cookie banner, no pop ups, no sponsored links or ads. Just amazing hand-crafted web content.

Can we give reference of these articles to LLMs and get them to write articles like this for educational contents and produce similar WebGL graphics code to render images. I mean, just use this style and produce educational content using AI. that might make the studies more interesting.

The Moon also plays currently a very special role in my life and my work days are dictated to a large extent by the current Moon phase :)

It's not discussed in the article but we have detailed models (ROLO[0] and LIME[1]) for how much light is reflected from the Moon and can be captured by a telescope. Like this one can radiometrically calibrate a telescope, that is, find a mapping between the digital numbers coming out from the sensor and actual radiance values.

[0] https://www.usgs.gov/media/files/rolo-lunar-model-and-databa... [1] https://acp.copernicus.org/articles/24/3649/2024/

> my work days are dictated to a large extent by the current Moon phase

Could you explain further?

At my current employer, Kuva Space, I'm among other things responsible for the commisioning and in orbit calibration of the payload. The Moon is a major calibration target for us, and between waxing and waining crescents I spent a lot of time analyzing Moon shots to perform radiometric calibration and camera parameter optimizations. The Moon doesn't know about weekends and images are not always downlinked at the most convenient times so that makes my life a bit more hectic.

My wife is a social worker at the county welfare office and swears there is a strong correlation between phase of the moon and the nature of her work with the homeless. To the point where where she checks the calendar to schedule more time for crisis handling around the time of the full moon.

Werewolf hunter? Sorority nurse? Doctor specializing in Cushing syndrome?

If you are interested in shaders, you can look at the source code. https://ciechanow.ski/js/moon.js

Like with all the other articles, it is straight up readable JS, with WebGL graphics, no dependencies.

This guy is a legend.

One file? Yeesh

Only kidding. Cool stuff, wish it were split up though

The very first interactive element is a great example of why ciechanow.ski is so great. Similar animations from other sources would probably limit to 28 frames and fake the image (using a simple mask). On ciechanow.ski there are hundreds(?) of frames and uses a bump map(?) to show accurate crater shadows on the moon's surface.

It goes way further than simple bump mapping. In terms of texture, there is a color texture and a height map, and the final rendering use real-time physically based rendering (PBR) techniques that takes into account the properties of the lunar regolith, as explained near the end of the article.

Color space is taken proper care of, and for images as rendered from the Earth point of view, there is a model of the atmosphere, so that the sky looks blue during the day and the Moon looks red at the horizon.

There are no pre-calculated images and only 3 photos. All the shading is done in real time using realistic models.

Which technology or frameworks is he using? The animations and interactivity are great.

Plain js and webgl

https://ciechanow.ski/js/moon.js

Just as the founding fathers intended.

I have same question. Is it simple <canvas>

WebGL.

One thing which isn't clear (from the animations at least) is how moon revolves around sun.

https://en.m.wikipedia.org/wiki/Orbit_of_the_Moon#/media/Fil...

When looked from distance, it looks more like revolving around sun while getting effected by earth. Which is to say, th motion does not look like a spring/spiral at all, but like a wave instead.

https://physics.stackexchange.com/questions/266426/what-does...

Minutephysics did a video about this: https://www.youtube.com/watch?v=KBcxuM-qXec

It looks like a dodecagon with rounded corners, but the video goes into more details.

This is the future of STEM education.

Well written, decently comprehensive interactive documents.

I think such formats should be prioritised instead of textbooks for creating learning materials.

I am really surprised almost no one is doubling down on something like this. Brilliant comes close, but its not at this level.

Everyone in Edtech seems to be running towards AI gimmicks.

Thank you Ciechanowski!

I've seen these called "explorables" or "explorable explanations" before and I really like them. I've been collecting notes on them here: https://simonwillison.net/tags/explorables/

Here's the website that coined the term: https://explorabl.es/

This is a really nice collection. Thanks for putting them together. I'm very partial to this writing style as well.

I took a crack at making it slightly nicer to write this style of blog post via markdown with codeblocks you can mark to execute instead of display (and hot reload + gist rendering support)

It makes the source easy to read, even on GitHub preview, etc.

It's what I've been using to write my recent posts.

https://github.com/jasonjmcghee/mdxish

But at the end of the day, content itself and the code that powers it is more important than any framework you might use.

That's a really neat system. Reminds me of Observable Framework, which I tried here https://github.com/simonw/observable-framework-experiments/b... to create this: https://simonw.github.io/observable-framework-experiments/pa...

ah ` echo` is smart - I didn't realize that would properly render in markdown editors / github, hence the comment approach.

That observable system you made here sure renders beautifully.

Thank you for collecting and sharing these. I was so impressed by the submission that my first thought was to find some repository that contains the samples of a similar caliber.

I consider Kerbal Space Program to be the most rewarding game I have ever played. Going into this page I was already somewhat familiar with many of the concepts it presented because I had encountered them during gameplay. However, having the ability to modify parameters was very helpful for visualizing different kinds of gravity assists. The game does not provide a way to do this, so it augments my understanding massively.

I agree that these interactive learning materials are incredibly promising towards actually understanding what is being presented. In other words, this is how I actually grok the concept.

Brilliant.org[1] does a good job of using explorables in their learning materials, some of the best I’ve seen in that category.

That said, Ciechanowski is on another level entirely.

[1] https://brilliant.org/

> I am really surprised almost no one is doubling down on something like this.

I've thought a lot about this – every time a new one is posted. I wish we could live in a world where this is what STEM education looks like. I think that, ultimately, it's just very high labor cost, and edtech is not known for being highly lucrative.

Bartosz does these as a labor of love, and the world is better off for it.

I do think that explorables are useful in understanding, but man I feel overwhelmed with them. I feel like I do my t know when and where to stop. I feel less anxious with a plain PDF or similar. I guess it's a skill issue.

We used to have those educational multimedia CD-ROMs back in the '90s. Look up Microsoft Encarta 97 on YouTube.

Wow, hats off to Bartosz! He has clearly poured so much time and effort into crafting this incredible blog. Hold on, though—check out their other articles too. Each one is a gem! Let's show some respect for his hard work—here's his sponsor link. Go ahead and support him!

https://www.patreon.com/posts/on-moon-118130286

Related personal story:

On January 6, 2023, at approximately noon, I happened to take a flight from Svolvær, Norway to Bodø, Norway, which, took me from 21.8 degrees latitude to 22.8 degrees latitude, which took me from [just inside polar night] to [just inside daytime].

I saw the moon at takeoff and the sun at landing.

It was an absolutely miraculous, specatular coincidence -- the latitudes I was flying over, the time, the date, the moon phase, the flight path.

This flight allowed me to have a full 3D view of space -- the moon, the Earth, the sun, all within an hour.

It was the first time I felt that the moon and sun weren't just discs flying around the sky randomly, but rather that I was the one flying through space, had a 3D sense of where the moon was behind me and where the sun was peeking ahead of me, and that the Earth felt curved as I moved out of the view of the moon and into the view of the sun.

My pictures and whiteboard illustration:

https://imgur.com/TYFAdoP

I’ve always wondered how different human culture would be if we had multiple moons. Related: the relationship between lunar and menstrual cycles is an open question, eg see https://pubmed.ncbi.nlm.nih.gov/3716780/ or https://pmc.ncbi.nlm.nih.gov/articles/PMC7840133/

Whenever these get posted I always play with it a bit, then look at the scroll bar and notice I'm about 10% through, if that. Has anyone ever read one of these to the bottom?

I guess in my mind this is just entertainment. I enjoy the visuals and interactivity, and marvel at the technical implementation, but I don't need to spend hours going through it. The only reason I would is if I actually wanted to learn this stuff, but so far nothing has come up that I need/want to learn at that level of detail.

I guess my question is, is this actually useful for education? Has anyone felt like they've really learnt something (ie. they could teach it to other people), after reading through one of these?

I have worked through a significant portion of the GPS one, and I learned a lot. I didn't do it in one go, though. Learning takes time.

It really is a marvel. I'm grateful society has such subject matter experts, that they have the technical skills to share it, have a passion to share it, and dedicate the time and effort to do so at such a level.

Bartosz Ciechanowski is a subject matter expert of everything, given enough time: https://ciechanow.ski/archives/. I still remember reading 'Gears' and being completely blown away.

On an unrelated note, on the Sunday we had a major lunar standstill i.e. the full Moon at its highest orbit (as seen from northern hemisphere). It happens every 18.5 years.

Wonderful ! Even if I am not super interested in the topic, the explanations are so clear and the animations so nice that I have admiration for the work done. Full mastery of the web medium that makes an explanation way clearer that any paper could. Would love to work on a similar projet on economics & personal finance. Thanks for sharing !

years back i came across this moon-related modeling problem on stackoverflow (i'm not the original poster)[0] and it's stuck with me that this seems like something that should have an easy solution.

An HN thread about how cool the moon is seems like a good place to resurface it.

But the question is this:

The crescent of the moon face is tilted based and the angle of that tile depends on the viewer's latitude on earth. Is there an equation that maps viewer latitude to the tilt of the moon crescent?

[0] https://stackoverflow.com/questions/22392045/calculating-moo...

This is why the internet is amazing!

Awe-inspiring. Beautiful.

How does the author build these pages? Looks like it is React. The entire blog must be custom built, no? Or is this built on top of an existing CMS?

No React to be found (and good riddance). It's two vanilla JavaScript files:

https://ciechanow.ski/js/base.js

https://ciechanow.ski/js/moon.js

Funnily, this JavaScript would not pass through most modern job interviews.

For those of us not in the know, why not?

Inconsistent style. Once global functions (that's so 2000), once prototypes (that's so 2010). No lazy loading, no modularization, no state management. Mixing variable declarations with initializations, one "var" declaration in the code. He probably haven't heard about TypeScript, transpilation, and doesn't understand static typing. Fells like a show off. That guy is an absolute no-no.

Was going to ignore this comment until the last 2 sentences. I rarely come across sites / articles that do this good of a job at explaining something I think calling it a "show off" and saying the author is an "absolute no-no" is a bit rude and I don't agree with it either. If anything I appreciate the code as it is, it's very readable at least to me.

My comment was /s of course. JavaScript from 2000-2010 era can do wonders especially if you leverage modern APIs and enormous performance of modern browsers, instead of silting it up with transpilation, frameworks, and layers of modules. Unfortunately simplicity is signalling a beginner and amateur in enterprise working environment.

Dang my bad, I feel silly for not catching the sarcasm in hindsight. Apologies.

17.6k LOC just for one post to educate and entertain people. Beautiful.

As usual, it's not the tech.. it's the business model.

Cheers...Chrome dev tools must have tricked me.

Also nice that the author didn't minify it. Interesting to read through.

Hand crafted, artisanal JavaScript.

You definitely don't need a CMS for a blog. I'd expect most HNer blogs you see here are either html files or markdown processed/styled into html files. I bet various templating solutions are popular too, which just output html files.

IME the reasons to have one are that you want people to comment and you want other people to write posts sometimes.

What an amazing exploration, from watching the sun set over moon craters in the first graphic to the simulation of how the Moon formed and the lucid explanations of tidal locking and axial precession.

As with many of the author’s posts, the underlying code can be an interesting read as well: https://ciechanow.ski/js/moon.js

I've already had the pleasure of learning from his previous post on 'Sound', and this one on the Moon is equally informative and beautiful. In the age of slop and pop-ups, it fills me with joy that there still exists on the internet such a brilliantly crafted blog that informs and educates the curious mind.

Something has gone terribly wrong when such beautiful, but essentially simple interactive graphics feel like an expensive and exotic gift, rather than something readily supported by widely used editors. A decade or more ago, I would've turned to Flash to create something like this, but now I wouldn't even know where to start.

Well, you could read his source code. He doesn't "use" anything, but if you want libraries I think Processing and Three.js are popular.

There's a collection of little facts I imagine being useful if a human got stranded somewhere in the universe and helpful aliens weren't sure where to take you. Without books and electronics, what could you memorize that would help them search and identify Sol/Earth in their big astral database?

This is one of them, the seemingly-pure-coincidence of solar eclipses where the apparent size of the moon equals the apparent size of the sun.

Ratios in general would be handy, since they would not depend on difficult-to-calibrate units: The moon is ~1/6 times the mass of our Earth; the biggest planet Jupiter/#5 is 2.5x the mass of all the rest and 5.2x the distance from the sun compared to Earth/#3, etc.

Once more extrasolar surveys are done it would be cool to see how unique we are. If something (possibly LLM based) could rate your description and see how many systems you'd have to visit to find Earth again.

"Eight major planets, the outer four are gas giants. Planets 2 and 3 are nearly the same size. All of the other planets, edge-to-edge, fit just inside the orbit of my planet and its moon."

> If something (possibly LLM based)

Whoah, hold the "AI" hype train there: I didn't design it that way, but an LLM is close to the worst possible thing you could use for this.

1. LLMs are incapable of real math or symbolic logic, so they aren't able to you whether your statement is approximately-true, and they can't tell you if it's useful either. (Lots of planets are spherical.)

2. You're trying to communicate with literal aliens that won't have any of that English training data the LLM draws from. They don't have any preconceptions about a "second" and "year" being related but one is bigger, they won't see the same colors or even have a 1:1 color sense, and they absolutely won't be inferring that Jupiter and Saturn are connected by pantheon-naming.

A lifetime exile from your entire species and culture is not something you want to leave to an LLM.

Ah, I think I wasn't clear enough and you misinterpreted me! I'm absolutely not suggesting an LLM for solving the "describe to aliens what our system looks like" problem or doing the assessment of our description.

I was trying to describe how, in the future when we have surveys of thousands of other star systems, it would be fun if there was a website that played the role of the aliens. We would describe to it in plain language what our system looked like and it would tell us if we did a good enough job to get home or not. To me, this means finding how many rows match in a database. I'm not sure how to turn plain language into a database query but, if pressed, today I'd reach for an LLM.

The initial simulations might give you a slightly wrong idea about the shape of Moon's orbit around the Sun. It doesn't form any loops (you can see that in the later more precise simulation) and is in fact convex (this one is a bit harder to see).

I can't tell you how excited I get everyone time he does a new one of these. They have all the delight and wonder of a child's pop-up book, but with the depth of a college text book. Consistently one of the best things on the internet.

I had to wait ten or fifteen minutes for a couple orbits to see if it would stick, but a little moon formed in the accretion example:

https://postimg.cc/Y4LTzLBk

This made me happy.

This is what JavaScript is for.

Is there a name for this category of website? I am seeing content like this — elaborate, animated, interactive — more often here and I wonder if its part of a new corner of the internet I am not familiar with. Looks dope.

I think this category is named ciechanow.ski.

https://explorabl.es/ calls them "Explorable Explanations".

It's hypertext - a text-based format enhanced with other elements.

Amazing idea!

There are even dedicated markup and scripting languages for this. I predict this technology will be hot in 2025.

I've even heard rumors of a data transfer protocol based on the concept.

Everything will be XML!

The moon is so interesting, easy to forget how much it affects life on Earth because we see it all the time.

Like others in the thread, I have a telescope and it's a wonderful experience pointing it skyward while it's still light out and the moon is visible. Then I can really see all the craters and "pock marks" on the surface. (My telescope isn't good enough to be able to see anything during a full moon, it all just becomes washed out.)

Huge fan of Bartosz. I love their posts. I saw the post link and it instantly put a smile on my face 'cause I know I would love it even before opening the link and the post did not disappoint.

In the 2nd graphic, they use of location to display the tiny person on the globe chef's kiss. The attention to details is brilliant. I am 40% through with the post and I couldn't contain my excitement to post here. This is lovely.

Could anyone recommend some introductory reading on orbital math? I had an idea rolling around in my brain for a while to make a little website simulating how various mathematicians and philosophers visualized the moon's orbit over the centuries, but I'm not great at math, lunar history, or math lunar history, so I'm curious where I'd get started on the reading.

Mathematical Methods of Classical Mechanics by Arnold is a good introductory book.

I'm guessing it will get nowhere close to as well considered, written, and structured as what Bartosz makes himself.

I don't know how people don't see how poor quality so much AI writing is, even when referencing good quality work.

Also making effective visualizations that do a good job of illustrating a concept is not just a matter of being able to write the code.

One thing I've noticed while looking at the Moon, the "dark" part is lit enough to see that it's an orb and not really being eaten by darkness. This webpage doesn't do that, I guess it's from a different perspective without the earth shining on the Moon.

I guess you alreay know this, but for reference this is caused by earthlight (light diffused and reflected by the earth): https://en.wikipedia.org/wiki/Earthlight_(astronomy)

Sometimes it's clearly visible, but often I agree that it's hard to tell if you're imagining it or not.

There's a short paragraph on "earthshine" towards the end.

I often wonder if it's just my imagination or is it really like that. I am still not sure.

Think of how when the moon is in the sky at night the ground on Earth is lit up and not fully black. Same with the moon, it’s not totally dark on the night side of the moon if the Earth is in the sky from the moon’s perspective.

Very cool. Question about the interactive image at the top of the page: why do the craters appear more distinct near the boundary of the dark and bright side of the moon and kind of much less on the brigh side surface far away from the boundary?

The craters appear more distinct because the low angle of sunlight casts long shadows. Where sunlight hits more from above, shadows are minimal, making the craters less pronounced.

Without even clicking I now know what it is going to be. Single word title and lots of votes.

I wonder if single word titles helps with SEO

https://www.google.com/search?q=Moon

right on front page #7 . good job

I could spend a lifetime trying and still not create a web page as spectacular as this.

I'm glad to know the author and me share the same earth (and the moon)!

Great as usual!

But I do prefer metric units.

As with all of his stuff, you can click on the unit to switch it to metric

You might also enjoy minutephysics video: https://www.youtube.com/watch?v=KBcxuM-qXec

Any time I see a new article on that domain, I know I'm going to be distracted from work for an hour or so while I have a great time. Bartosz, your work is amazing.

Amazing interactive article. It actually gave me hope in humanity, over LLMs. I could feel the love, creativity and effort that was put into it.

Some of those interactable visualizations on scale and seeing the sun/moon/earth rotate at the same time is the best anywhere.

“And still, after all this time, the Sun has never said to the Earth, "You owe me." Look what happens with love like that. It lights up the sky.”

― Rumi

We like the moon! Because it is so close to us.

And now I want a hot toasty sandwich.

Do you know Which technology or frameworks is he using?

The animations and interactivity are great. I'm really impressed.

It’s almost all handmade. And he uses a lot of scripts to generate his scripts.

Pretty cool post! I thought I knew the moon, but after your post I guess I was wrong haha

Your journey from frustration to fascination with the moon is truly inspiring and beautifully captured!

The other side of the moon looks quite different to the tidally locked side we see from earth.

Miles deep in to what seem like a subject we take for granted in everyday life.

This is a fantastic example of why the Internet can still be a magical place

the author is different gravy

It is fascinating how much the Moon matters to us, yet it is largely ignored.

His blog posts are always amazing, very detailed and exceptionally visual

The solar system is like a mechanical clock, a timepiece.

This feels like a beautiful work of art! Great job, OP!

Moon should be a state

Thank you, I am going to show parts of this to my daughter!

This cracks me up. "Look at these beautiful orbital paths. Cover your eyes when it's explaining the barycenter. Cover your eyes!"

as a kinesthetic learner I really cannot say how invaluable the interactive widgets are, so wonderfully done.

De revolutionibus orbium coelestium

wow. can you imagine the amount of work that was put into this website?

A big ass ham sandwich too.

I haven’t read the article but Bartosz articles are so good and enjoyable to read that I get excited whenever I see a new one pop up. I have already set some time aside tonight to read it with care.

Bartosz if you are reading this: thank you so much for these articles. You truly are an inspiration and I can only hope one day I get to be as good a communicator as you are.

Wow! Just wow! Very good.

Wonderful! A masterpiece.

Bartosz, your website is the most beautiful, glorious thing to ever grace my browser. I’m not even sure how to put it into words, but I LOVE YOU for doing what you do. Thank you for your brilliance. Thank you for making my day every time I visit. Never change. Please, just keep on being your awesome self.

ciechanow.ski on the frontpage? Instantly upvoted.

Holy crap! only afew hours ago i was scraping his site and hoarding the delicious javascript. I wondered how long its been since the airfoil post and, bam! , a new article! More juicy javascript to hoard!

> It was also the very first image I was actually not embarrassed to share - https://imgur.com/a/t9b1Uug

I was goofing around with the ciechanowski moon model and noticed that either this image or ciechanowski's simulation is flipped 180 (mirrored not rotated).

https://ciechanow.ski/moon/

So I googled moon images to see which one might be flipped (it would be amazing if the ciechanowski model was inverted) but after looking at about 100 images, 90/100 or more seem to be composites based on the same image. Not just that the moon presents the same face, but all the google results look based on literally the same image. So what if that image is flipped?

On an oblique note, I assume google reports such repetitions to almost any search— I've noticed there's a web dark pattern for results repetitions; see Amazon and Netflix. And AI results appear to be an obscenely amped-up repeater.

I'm interested in repetitiond news too: take Google news without any personalization— how the web may create an appearance of copious information that's actually very limited, and maybe very biased or completely wrong— e.g., Mandela Effect.

For example news of U.S. foreign affairs is routinely absurdly biased and narrow, such as the new leader in Syria leading "rebels" as in SW rebel alliance and not noting we've got a $10,000,000 bounty on his head for being a terrorist.

(Ask what you can do for Russia, not what Russia can do for you)

I keep second-guessing my own perceptions, like I'm cherrypicking, but the effect seems rampant, where very narrow and obviously contestable views are repeated as truisms and appear as such across many outlets.

I just saw a documentary called "The Program" which one more in and endless series of hype products about UFOs— this one tries to politicize the topic as a huge coverup a la JFK.

But what seems funny to me is term UFO! It's a fascinating term in its own right as it is used as a determinative noun based on an acronym where the key trait is "unidentified". In the truest sense all studies of UFOs must reveal nothing, by definition. And they do reveal nothing. As did this documentary. You may have never noticed, but nothing is something!

The moon is sort of like this: the biggest nothing in world. Does it even matter which is right (vs left vs correct) view?— I can't be bothered to look up. Besides some guys went there and all they found was rocks. Who would have guessed?! They brought some back and they've been completely forgotten about and misplaced out of boredom and irrelevancy.

It was more interesting when the noon could still possibly be green cheese. Now it's just orbital mechanics— a celestial pinball machine. A giant fusion reactor pours energy out across a gradient and somehow gives rise to everything we are. (Yawn, I'm sleepy).

Newton on gravity:

The last clause of your second Position I like very well. Tis unconceivable that inanimate brute matter should (without the mediation of something else which is not material) operate upon & affect other matter without mutual contact; as it must if gravitation in the sense of Epicurus be essential & inherent in it. And this is one reason why I desired you would not ascribe innate gravity to me. That gravity should be innate inherent & essential to matter so that one body may act upon another at a distance through a vacuum without the mediation of any thing else by & through which their action or force {may} be conveyed from one to another is to me so great an absurdity that I beleive no man who has in philosophical matters any competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly according to certain laws, but whether this agent be material or immaterial is a question I have left to the consideration of my readers.

Fantastic!

Amazing!

Amazing

bravo, really clear

Another masterpiece I am sure!

Wake up babe, new Bartosz Ciechanowski post dropped

Easily one of the best sites on the internet, in my opinion

Meredith, clear the rest of my day.

I saw the domain name and thought the same thing. Always an event to see a new post of his.

I was just thinking about him yesterday while browsing HN, wondering when the next post would drop.

There was a post earlier today about mechanical watches, of course this site was linked again.

Early Christmas present!

An order of magnitude above and below the speed of a falling object - exporting the JSON file that has its unadulterated gravitational force data. Dark matter and Newtonian mechanics are epiphenomenal modes of interlocking processes.

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