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What is Bartosz Ciechanowski?

Bartosz Ciechanowski is a personal website that publishes interactive articles explaining science and engineering topics. Instead of static text with a few diagrams, each article embeds manipulable simulations: you drag, zoom, and move sliders to change a viewpoint or a moment in time, and the explanation updates as you do.

The site describes itself simply as "interactive articles about science and engineering," and the range of subjects follows that description rather than a single narrow field — physics, astronomy, mathematics and engineering mechanics all appear. The author's name is the site's name, so this is one person's body of explanatory work rather than a magazine, course platform or company publication.

What an article actually feels like

The Moon article is a useful example. It opens with the Moon as seen from space, which you can drag to change your angle, plus a slider for date and time. It then moves to a panorama of the sky from a point on Earth, where you drag to change your viewing direction and adjust sliders to watch the Moon's position shift across days and hours. A small figurine on a globe can be dragged to another location, and a button can place it at your current position if the browser permits.

That structure is the point: abstract ideas about orbital motion, illumination and apparent wobble become something you test by moving the controls yourself. The writing still carries the explanation, but the demonstration is the primary teaching device.

Who gets the most from it

• Curious non-specialists who bounced off textbook treatments and want to build intuition by experimenting.
• Students using an article alongside a course, particularly for spatial or mechanical topics where a static figure is hard to read.
• Teachers and explainers looking for a reference model of how to make a technical idea explorable.
• Programmers and designers interested in how interactive explanations are built, since the craft is as visible as the content.

The trade-off is that it suits patient, hands-on reading. If you want a quick factual summary or a structured syllabus with exercises and assessment, a conventional reference or course will serve you better. There is also no substitute for a textbook when you need formal derivations and problem sets.

How to decide whether to spend time there

Pick one article on a topic you already understand reasonably well and work through it with the controls. If the interaction teaches you something a paragraph alone would not — a relationship between variables, a change over time, a three-dimensional geometry — the site's approach is worth your attention for harder subjects too. If you find yourself only reading the prose and ignoring the sliders, the format is not adding much for you.

For comparison, Bartosz Ciechanowski sits closest to other interactive-explanation projects such as Distill for machine-learning research writing, while Explorable Explanations collects interactive work from many authors. three.js is the kind of browser technology behind many such simulations, if you are more interested in building one than reading one.

How can I use the interactive simulations to understand the Moon's orbit and phases?

The site’s Moon article is built around two linked kinds of interactive simulation: a space view where you can drag the camera around the Moon, and an Earth-based sky view where you control date, time and viewing direction. The first helps with geometry (what the orbit and lighting look like from outside), the second with observation (where the Moon actually appears in your sky and how its lit face changes over hours and days).

What each simulation is good for

• Space view, draggable camera: Drag to orbit the Moon and see craters and mountains from different angles. Use it to build intuition for why the Moon’s appearance from Earth depends on the Sun–Earth–Moon geometry, not on the Moon changing shape.
• Date and time slider: Move through days and hours to watch the Moon travel an arc across the sky and almost complete a loop around Earth over one day. This is the fastest way to connect “one day” with “one orbit” without waiting for real nights.
• Sky panorama: Drag the panorama to look above and below the horizon, and use the arrow to locate the Moon. This shows how much of the Moon’s daily path is above your horizon and how that changes with time.
• Location figurine: Drag the figurine on the globe, or let the page place it at your current location, to compare how the sky looks from different places on Earth. This is useful for understanding why the Moon’s path and phase timing are local, not universal.
• Zoom and lock on the Moon: The article zooms in and locks the camera on the Moon so you can see its apparent rotation over a single day and a visible wobble over many days. That wobble is what occasionally exposes parts of the far-side edges, even though we normally see only one side.

A practical way to use them together

1. Start in the space view and drag around the Moon until you can predict which side is lit.
2. Switch to the sky view, set your location and a date, then step the time slider through one day. Note when the Moon rises, when it is highest and when it sets.
3. Step the date forward across about a month and watch the illuminated fraction change. Try to predict the next phase before moving the slider.
4. Return to the space view and reproduce the same date and time. Check whether your mental model of the Sun–Earth–Moon alignment matches what the simulation shows.

Trade-offs and audience

The simulations reward curiosity and repeated play; they are less useful if you want a single static diagram or a quick answer. The space view gives you freedom of motion you never have from Earth, which makes orbital geometry clearer but can make it harder to relate to what you see outside. The sky view is more directly observational, but the Moon is small and easy to lose, which is why the article zooms and locks the camera. The article is in English and assumes you are comfortable dragging sliders and reading a globe; it suits students, teachers preparing demonstrations and anyone who learns better by manipulating a model than by reading a textbook.

If you want a concrete next step, open the Moon article and try this: pick tonight’s date, set the figurine to your location, and note the Moon’s position and phase. Then move the date forward one week and try to explain the change using only the space view before checking the sky view again. For background on the author’s other interactive science and engineering articles, see Bartosz Ciechanowski.

What interactive articles about science and engineering are available on this website?

Bartosz Ciechanowski publishes long-form interactive articles that explain science and engineering topics through manipulable simulations rather than static diagrams. The site's own description frames the collection that way: "Interactive articles about science and engineering." The clearest documented example is "Moon" (December 17, 2024), which walks through the Moon's orbit and its appearance in our sky.

What the Moon article actually lets you do

• Drag a 3D view of the Moon to change your vantage point, and use a slider to move through dates and times.
• Pan a sky panorama above and below the horizon, with an arrow marking the Moon's position.
• Drag a figurine on a globe to see the sky from different locations on Earth, or let the page place it at your current location if your browser permits.
• Watch how the Moon's illumination changes over days, and see its apparent rotation across a single day and its wobble over many days.

That mix — a free camera, a time slider, a location control — is the pattern the site applies to its subjects: you build intuition by adjusting variables and watching the result, not by reading a derivation first.

Who gets the most out of it

Readers who already know some physics or math but want a spatial, hands-on feel for a concept. A student who can recite that the Moon shows one face to Earth may still be surprised by the daily rotation and multi-day wobble the article demonstrates; the simulation makes those effects visible in seconds. Teachers can use individual demos as in-class illustrations. Casual readers should expect to spend real time with each article, since the interactivity rewards experimenting rather than skimming.

How to choose what to read

Next step: open the Moon article first as a format sample, then browse the archive to find a topic you're currently studying. If the style clicks, similar interactive-explanation work appears at Distill and Explorable Explanations, though their coverage and depth differ from this site's.

How does the Moon's libration allow us to see more of its surface?

Libration is the slight rocking of the Moon that lets observers on Earth see a bit around its edges, so we see more than exactly half of the lunar surface over time. The Moon still keeps one face pointed generally toward us, but its orientation and our viewing angle shift enough to expose extra slivers near the limb.

Bartosz Ciechanowski's interactive article demonstrates this directly. In the page evidence, he notes that across a single day the Moon seems to rotate, and over many days it "quite visibly wobbles," allowing us to "occasionally see some hidden parts on the 'edges' of the Moon" while it still shows only one side overall. The article's sliders for date, time and viewing location let you watch that wobble change the visible edge. You can explore it at Bartosz Ciechanowski.

What causes the wobble

The effect comes from several small mismatches between the Moon's rotation and its orbit:

• Libration in longitude: The Moon's orbital speed varies while its spin is nearly uniform, so it appears to turn slightly ahead or behind.
• Libration in latitude: The Moon's axis is tilted relative to its orbit, so we sometimes look slightly over one pole and then the other.
• Diurnal libration: Earth's rotation carries you from one side of the planet to the other during the night, changing your viewing angle by about the width of Earth.
• Parallax: The Moon's distance and your position on Earth's surface shift the apparent edge slightly.

Why it matters

Libration is the reason a long-term observer can eventually map more than 50 percent of the Moon. It is also useful when planning observations: a crater or mare near the limb may be invisible on one night and clearly presented on another. For a practical next step, open the article's panorama, set the date slider to move across many days, and watch the arrow and the visible edge; then compare that with a simple Moon-phase calendar to see when a limb feature is best placed.

Can I simulate the Moon's position in the sky for my location and time?

Yes. On Bartosz Ciechanowski, the Moon article includes an interactive sky simulation where you set your viewing direction and scrub through days and hours to see where the Moon sits above or below your horizon. A figurine on a small globe can be dragged to any location on Earth, and if your browser permits it, a button places that figurine at your current location automatically. The page also lets you click or tap to follow an on-screen arrow pointing to the Moon.

What you can actually do

• Drag a panorama to change your viewing direction, including below the horizon.
• Move sliders for date and time to watch the Moon's position shift across days and hours in local time.
• Relocate the figurine to see the sky from a different place on Earth.
• Use the automatic current-location option as a shortcut to your own sky.
• Switch to a separate space view where you can drag the Moon around and pan the camera freely to inspect craters and mountains from any angle.

How the two views differ

A practical way to use it

If you're planning to observe the Moon tonight, first set the figurine to your location, then drag the time slider forward hour by hour. Watch the arrow and note when the Moon sits comfortably above the horizon and how its illumination changes over the following days. Then switch to the space view to see why the lit portion looks the way it does from your angle. For an independent check of rise and set times at your exact coordinates, compare with a dedicated almanac or planetarium tool such as timeanddate.com or Stellarium.

How can I support Bartosz Ciechanowski's work on interactive articles?

The site itself lists a Patreon page among its links, so becoming a Patreon supporter is the most direct way to fund new interactive articles. The page also links to an email address and social accounts, which are better suited to feedback, corrections or sharing an article than to financial support.

Practical ways to help

• Patreon: The recurring route the site points to; useful if you want to support ongoing article production rather than a one-off.
• Share a specific article: These pieces are built to be played with, so send one to a teacher, student or colleague who would actually use it. A link to the Moon article, for example, is more persuasive than a general recommendation.
• Send a correction or suggestion: Technical accuracy matters in this kind of work, and a concrete, well-sourced note is genuinely useful.
• Use it in teaching: If you run a class, assigning one of the simulations gives the work a practical audience and shows what the format can do.

What not to expect

There is no evidence of paid tiers, gated content or a shop on the site, so treat support as voluntary patronage of an independent writer rather than a purchase. If recurring payments do not suit you, sharing the work and using it in your own teaching or study are the next most useful things you can do.

Start with the support link on the site's own page, then pick one article and pass it to someone who will use it.