Earth and Sun

https://ciechanow.ski/earth-and-sun/

by davezatch • 7 years ago

701 63 7 years ago

ciechanow.ski

excalibur• 7 years ago

Amazing how he got the clouds to stand still for an entire year :)

lxe• 7 years ago

This is excellent. Are all the interactions custom made?

sixQuarks• 7 years ago

I’d like to know what tools were used to make these. Works great on mobile, usually these things break pretty badly, I didn’t see any bugs

novaRom3• 7 years ago

Works excellent in Firefox

d6e• 7 years ago

Looks like it's just hand written javascript and webgl https://ciechanow.ski/js/earth_sun.js

airstrike• 7 years ago

One of the many ways you can tell how much passion went into this beautiful piece

novaRom3• 7 years ago

Very good made! I recently started astrophotography, it is a lot of fun. Just learning all those different stars and galaxies, it's incomprehensible how big is the space. Nice thing it's really doable to appreciate it live from your backyard. A lot of technical things are still desirable, a big opportunity for innovative ideas.

naringas• 7 years ago

really good, I wonder if there's a "Earth and Moon"?

ryanseys• 7 years ago

If you would like to make it yourself, check out my library! https://github.com/ryanseys/lune

folli• 7 years ago

Very well made and very educational!

An often used algorithm for the calculation of the apparent sun position (given a date and latitude/longitude of the observer) is SPA of Reda et al. [1]. If you're interested, I wrote an Android app (Sun Locator [2]) that implemented this algorithm.

[1] https://www.sciencedirect.com/science/article/abs/pii/S00380...

[2] https://play.google.com/store/apps/details?id=com.genewarrio...

novaRom3• 7 years ago

It's like I just read an epic story, still under impression ...

Quote: One day we’ll colonize other planets, those planets will have different suns, orbits, and rotations periods, yet a simple second will forever be tied to Earth and Sun.

I would definitely give my 'best web page 2019' to it. Bravo!

twic• 7 years ago

I remember spending a lot of time playing with a planets-and-gravity simulator on the Mac when i was a kid. I wrote a crappy clone of it as an applet for one of my first jobs!

This is the best web-based equivalent i found with a quick search:

https://hermann.is/gravity/

And this is a rather fine tutorial on writing your own:

https://css-tricks.com/creating-your-own-gravity-and-space-s...

perl4ever• 7 years ago

I played with a simple program like that for the Amiga when I was younger, and then I discovered that there was an O(n log n) algorithm[1] rather than the obvious O(n^2) one. Never was up to writing a program to use it.

https://en.wikipedia.org/wiki/Barnes%E2%80%93Hut_simulation

m0skit02• 7 years ago

I highly recommend Space Engine https://store.steampowered.com/app/314650/SpaceEngine/

bitpow• 7 years ago

What a beautiful, well designed and informative explanation of the complex earth / sun relationship. Well done!

One thing I would love to see is the path of the sun across the sky for different times of year, and different locations on earth.

Here in Seattle, the difference is fairly dramatic between winter and summer, and I've come to realize that the sun is never directly overhead, not even in summer. It would be interesting to see the difference between polar regions vs in the tropics also.

haberman• 7 years ago

Very much agreed. Things get weirder and weirder as you get towards the poles. At the poles themselves the sun spends half the year hidden, and the other half spiraling up and then down! But never gets very high above the horizon.

I've been thinking a lot about this lately and was thinking of making some educational YouTube videos about it!

TheSpiceIsLife7• 7 years ago

If you haven’t looked at that sort of thing on YouTube, don’t. Make your own videos first.

saberdancer2• 7 years ago

Perhaps you are aware, but it is very simple to calculate.

(90-your latitude) + tilt of the earth (23.5 degrees) = maximum height of the sun during the year

(90-your latitude) - tilt of the earth (23.5 degrees) = minimum height of the sun during the year.

Effectively this means if your latitude is 23.5 or less, you get the sun directly overhead at some time during the year. If your latitude is above 67.5, you get polar night as the sun doesn't rise above the horizon (short one at 67.5, but as you go further toward the pole ever longer)

For Seattle, (90-47)+23.5=66.5 maximum. (90-47)-23.5=19.5 minimum.

thaumasiotes• 7 years ago

Calling these the "maximum height" and the "minimum height" of the sun during the year makes it sound like the height of the sun will always lie between those two figures. That can't be the case -- they have night in the tropics too. Are these what I might call the "high maximum height", the yearly maximum of the maximum height of the sun on any given day, and the "low maximum height", the yearly minimum of the daily maximum height of the sun?

elliottkember• 7 years ago

At my school we had this weird climbing frame called the "Pipehenge". I climbed on it for years before we eventually did a class on it and learned that it was an astronomic map: https://www.youtube.com/watch?v=BM4d02tjTqk

TheSpiceIsLife7• 7 years ago

I’d love to make one of those

Tepix• 7 years ago

Looks they are no longer made, or are they?

zargon• 7 years ago

SunCalc (http://suncalc.net) has a visualization for sun position throughout the year and time of day. Another great app is Sun Surveyor for Android, which gives an augmented reality view of the sun's position and trajectory.

bostonpete• 7 years ago

I've come to realize that the sun is never directly overhead, not even in summer

It's only ever directly overhead in the tropics.

emmelaich• 7 years ago

.. which is defined to be between the tropic of cancer and tropic of capricorn; 23°26′12.2″ north and south of the equator respectively.

gattr• 7 years ago

The free, cross-platform program Stellarium [0] will show that (among other things).

[0] http://stellarium.org/

beders• 7 years ago

This was fantastic! Thanks!

macrael• 7 years ago

This is what the web is for. Charming, intimate. Thank you

carrozo• 7 years ago

This is so excellent. Put it on school curricula!

kwoff• 7 years ago

Very nice visualization. It'd be interesting to see it extended to the galaxy, as in https://www.physicsforums.com/threads/orientation-of-the-ear...

oska5• 7 years ago

The Earth rotates around its axis from west to east, or, when seen from above, counter-clockwise.

North is not up.

When seen from above the South Pole, the Earth is rotating clockwise.

But really doesn't make much sense to talk about the rotation of a sphere by analogy to a 2D clockface. The Earth rotates from West to East; that's all that needed to be said here.

mathgladiator• 7 years ago

Dont all maps have north 'up's? I'm curious if there are maps that invert this.

oska5• 7 years ago

We're not talking about a map here, we're talking about the real thing, the Earth, hanging in space.

(But yes, there are many maps that don't have north at the top).

kderbe• 7 years ago

An example of a south-is-up map: http://mapdesign.icaci.org/wp-content/uploads/2014/01/MapCar...

mrfusion2• 7 years ago

I’m not sure if it’s related but I can’t seem to understand the international date line.

cuspycode2• 7 years ago

The international date line is needed when you use local times instead of UTC, because the local date is incremented on midnight local time. So, if it's October 19 just after your local midnight, every timezone to the east should also have October 19, while every timezone to the west should still have October 18 because they haven't had local midnight yet. But that doesn't work, since east ultimately meets west when you track both directions far enough. So by convention we have defined a line (or rather a crooked boundary between timezones) where the date jumps back a day in the calendar when you pass over it in an eastwards direction.

mrfusion2• 7 years ago

Thanks but that much I understand. I guess for people living in that border it doesn’t make sense to me how they can jump back and forth 24 hours.

olivermarks• 7 years ago

this is wonderful

disqard• 7 years ago

I used it on an iPad. For me, this was a beautiful example of how to leverage the strengths of a touchscreen to present information. (too often, I find myself shaking my fist at how we’ve "bolted" a magazine onto a high-dpi display)

Wonderful stuff... thank you for making and sharing!

known• 7 years ago

This is the best I've seen till date;

baxtr• 7 years ago

I can’t upvote this enough. Beautifully crafted website

exiladodecapela• 7 years ago

Excellent work!

pacoverdi• 7 years ago

Wow. What a great explanation. I'd love it to be translated in other languages so I can have my younger kids spend some useful screen time on it!

trileansoftware• 7 years ago

Are all the interactive infographics custom made? Amazing.

ColinWright• 7 years ago

This is absolutely superb - just brilliant.

This is a personal reflection on the way it's presented. I'm sure that there are people who already know some of the content, and I found myself skimming over things, nodding, and thinking "Nothing new here." Then realised that there was something I missed, or an explanation that was especially nice, and I had to go back and re-read, wondering what else I might have missed.

So I found it all very smooth, clean, informative, but there was no story, no arc, no narrative, nothing to make me want to sit with a coffee (or other beverage of choice) and simply read like a novel. There wasn't the "Hook; Narrative; Reveal" structure that keeps the reader involved.

Which is a bit of a shame, because the bits I did take time over are really, really nice.

It's really nice.

justajester• 7 years ago

wow. Excellent read. much respect. Labor of love.

m0skit02• 7 years ago

Excellent visualization of these astronomy concepts, amazing job, my sincere congratulations!

srigi• 7 years ago

Last couple of months I started thinking about sidereal vs. solar year. The first one is determined by distant stars, the second one by our Sun.

The thing I'm thinking of is if small deviations accumulate over years, how night sky is changed at the same date across, let's say, 20 years?

beerandt2• 7 years ago

If you think that can get complicated, check out the different global geodetic reference systems. Between the Earth's precession, plate tectonics, the Earth changing mass cyclically (collecting space debris and off-gassing atmosphere), and the fact that the center of our planet is a freaking wobbly blob of molten iron, well, things can get tricky.

Then there are the different eliosoidal (and soon geoid with NVD22) shapes that are the basis for every other reference system, most based on similar, but slightly different geodetic network adjustments. Some systems, like NAD83, remain relatively fixed in reference to a particular land mass (North America Datum 1983). Some will then progress with the land mass as it moves on the Earth's plates, others will remain fixed based on a (the) prime meridian, or in reference to the center of gravity of the Earth as it shifts, or in reference to Polaris, etc.

So now you have multiple measuring systems each referencing different geometric/geodetic/astronomic points/lines, and further it matters what time it was when you defined those points/axises. WGS80 is the basis for many modern systems, including NAD83. ITRF is similar, but defines a yearly amount of progression since ~1980 to account for things like continental drift. They coincided around the time when they were defined, and have been diverging some number of millimeters per year since then.

Once you agree on a definition of a system, you further have to define how to measure it. Will North be a point in time, or a rolling average? Will the center of gravity of the Earth be based on changing rate of Earth's rotation, or with respect to a geodetic benchmark or network, or maybe based on millimeter fluctuations in deviations of the orbits of the NAVSTAR / GPS satellites? Should Euro/ Chinese/ Russian / Indian versions of GPS satellites be taken into account?

I'm over simplifying things, as there are additional layers of complexity involving the actual tools for surveying and measurement, the precise steps for any network adjustments or translations, rounding rules and certain geometric assumptions made for different types of math, and way, way more. (You can't actually stretch a tape measure around the equater.)

Take all of that, and then contemplate how all of this is spinning around arbitrarily in space. Sidereal vs solar is only one of 100s of aspects of how we measure these things. It's not just time, but also geometric space.

Everything's relative.

beerandt2• 7 years ago

Also, you can try to explain this to people, most of whom will complain that it's way too complicated, and we don't need anything to be that precise. They say it's ridiculous.

Then you can ask the same person for directions to their house, and they'll turn around and text you GPS coordinates to 12 digits.

cosmosa• 7 years ago

This is excellent. I had been wanting to see something like this for a long time. It was difficult for me to imagine the orbit of earth around the sun, and nothing I found showed it well. Thanks for making this!

Earth and Sun

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