4 ms·
When will the eclipse happen? A multimillennium tale of computation
- stblack 3y agoMathematica's SolarEclipse[] function, introduced in v10 and seriously updated in v14, is a gem. https://reference.wolfram.com/language/ref/SolarEclipse https://reference.wolfram.com/language/ref/SolarEclipse
- m463 3y agoI wonder if he wrote it.
- brcmthrowaway 3y agoIncredibly esoteric functions, the hallmark of Mathematica!
- 7thaccount 3y agoI'm a big fan of Mathematica even though all commercial software irritates me on some level (transparency, cost, and licensing annoyance). As a result I follow Stephen's blog and sometimes they come off as a little self serving and grandiose, but this one was terrific to me as a non physicist in better learning the history and challenges of all of this. It's hard to understand sometimes that celestial mechanics is simply not a "solved" problem these days.
- deleted 3y ago[deleted]
- javajosh 3y agoWhat a truly lovely piece of work. I'm so glad that Wolfram adores math and science, and history, so much and has the tools to craft an excellent precis like this. It's always good to go to original sources, and connect with the deep past of learning to which we are the grateful inheritors. Predicting eclipses, and the details of how it was and is done, is probably considered by many to be pointless, boring, or even harmful (stealing intelligent attention away from more pressing problems, or any number of other reasons). But I think it's beautiful to retell these stories and appreciate them and the minds behind them. There is something so entirely wholesome about a learned man appreciating the work of his forebears. Wonderful.
- BoiledCabbage 3y agoAgreed, it was a really nice read. Even simply in the role of an educator I've taken a liking to his blog posts. There is a certain combination of both breadth and depth that I've not found anywhere else. His overview of how LLMs work from last year was on of the first really good pieces describing them truly from first principles. And still shapes how I describe their workings to people outside of tech.
- huppeldepup 3y agoFYI, this site shows an nice plotted overview per region and period of time: https://www.timeanddate.com/eclipse/list.html?region=europe https://www.timeanddate.com/eclipse/list.html?region=europe
- pixelfarmer 3y agoMore specifically: https://www.timeanddate.com/eclipse/solar/2024-april-8 https://www.timeanddate.com/eclipse/solar/2024-april-8
- wrycoder 3y agoI have the Classic Wolfram app on iOS. I asked it, “When is the next partial Solar eclipse in New Hampshire?” It missed the 2024 one and started giving details about a 2026 eclipse in Spain.
- sockbot 3y agoIs there a closed form solution for this or is it an example of the three body problem?
- zamadatix 3y agoSee the "The Three-Body Problem" and several following sections. The fixed geometric approximations earlier in the article can have a closed form though.
- hinkley 3y agoI can’t believe that when the last time this eclipse happened my friends had to twist my arm into pausing whatever important thing I was doing to go outside and see it because this wouldn’t happen again for thirty years, in 2024. I would be SO OLD then and probably not living there anyway so seize the day! Fuuuuuuck.
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- Archelaos 3y agoThe author does not give sufficient credit for a particular difficulty in calculating the location of a solar eclipse. He mentions in pathing that "the rotation of the Earth is gradually slowing down" and that "exactly when a new leap second will be needed is unpredictable". More precisely, he should have said that the Earth's rotation has a tendency to slow down - in contrast to today, it accelerated somewhat in the last third of the 19th century, for example. But more significant in this context, however, is the aspect that the estimation of the degree of change for a given period of time becomes quickly more and more inaccurate when we go forward or backward in time. In the case of ancient eclipses we cannot calculate their exact location from a prior knowledge of the Earth's rotational speed. It is the other way round: since we have historical reports from a particular region about an eclipse we can deduce the change in the Earth's rotational speed between now and then. For more information about the change of Earth's rotational speed see the Wikipedia article on "ΔT (timekeeping)": https://en.wikipedia.org/wiki/%CE%94T_(timekeeping) https://en.wikipedia.org/wiki/%CE%94T_(timekeeping)
- andersa 3y agoWhat if we could add giant engines to control the rotation speed and fix this leap day/second nonsense once and for all?
- teddyh 3y agoI guess you would have to anchor those engines pretty deep. I would assume that even anchoring them to bedrock would simply cause unscheduled continental drift, and possibly only mountainous relocations.
- HowardStark 3y agoGoofing a bit, but couldn't you damn the Madeira river and then use the flow control to speed up/slow down the rotation of the earth[0]? [0] https://en.wikipedia.org/wiki/Three_Gorges_Dam#Terrestrial_impact https://en.wikipedia.org/wiki/Three_Gorges_Dam#Terrestrial_i...
- quinncom 3y agoWolfram’s Precision Eclipse website gives the wrong time for the eclipse at my location (23.7188, -105.6706). It says, “Total Eclipse begins at 1:09:31 PM CST”: https://precisioneclipse.com/Results/46/b7/46b7ed589f764aec.html https://precisioneclipse.com/Results/46/b7/46b7ed589f764aec.... In fact, C2 will be at 18:09 UT, which is 12:09 CST (-0600): https://eclipsewise.com/solar/SEgmapx/2001-2100/SE2024Apr08Tgmapx.html#map https://eclipsewise.com/solar/SEgmapx/2001-2100/SE2024Apr08T... Can anyone confirm the correct time? I wonder if precisioneclipse.com isn't considering that Mexico abolished daylight savings since Oct 2022.
- bombcar 3y agoThat’s almost certainly it - I don’t know they abolished it entirely; it used to be offset a few weeks.
- isx726552 3y agoThe US Naval Observatory has an online calculator which is accurate and time zone agnostic: https://aa.usno.navy.mil/data/SolarEclipses https://aa.usno.navy.mil/data/SolarEclipses
- quinncom 3y agoThat's a good one, thanks. It gives me `18:09 UT`, which is `12:09 CST`. The Precision Eclipse calculator does seem to provide correct results in the US (e.g., 1:40 PM for Dallas TX). So, it must be a Mexico timezone calculation error.
- heikkilevanto 3y agoThe Anticythera Mechanism was able to predict eclipses some 2000 years ago. Anyone know if its predictions would still be useful?
- dmd 3y agoThat is discussed extensively in the linked article.
- xvilka 3y ago[flagged]
- libraryofbabel 3y agoYes, great article and actually an astonishingly low amount of awkward-dad bragging by this particular author’s standards —- the closest he got was slipping in how he was ALSO at the Institute for Advanced Study “in Princeton” when Otto Neugebauer was there in the 1980s. And he probably considers himself a peer of Isaac Newton but hey, don’t we all from time to time? Maybe he’s been reading the HN discussions of his articles and decided to tone down the boasting. One can hope.
- pvg 3y agoThese tangents are fairly rare on HN and it's a good idea to keep it that way due to their exceptional boringness: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=by%3Adang%20wolfram%20derangement&sort=byDate&type=comment https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
- deleted 3y ago[deleted]
- dataflow 3y agoBest website I've seen is this: https://eclipse2024.org/eclipse_cities/statemap.php https://eclipse2024.org/eclipse_cities/statemap.php Click a location, then open the simulator for that location.