Magnetic Dipoles
iron filings tracing a magnetic field

What you see on every new tab

Magnetic Dipoles turns the New Tab page into a near-black plate covered in thousands of short brass-coloured filings, one roughly every 15 pixels. Three bar magnets sit on the plate, each shown as a soft warm glow with a red north tip and a blue south tip, and every filing turns to point along their combined magnetic field.

One magnet follows your cursor. The other two circle the middle of the screen and spin as they go, so the loops between the poles stretch, merge and split again as the magnets pass each other.

• Three magnets: Your cursor magnet is slightly stronger than the two wanderers, which take over a minute to circle the screen and turn in opposite directions.
• Brighter near the poles: Filings close to a magnet glow brighter and grow longer; far out on the plate they fade to faint short dashes.
• Field-line loops: Between a red tip and a blue tip the filings bend into the arcs you get by sprinkling iron filings on paper over a magnet.
• Never quite a grid: Each filing is nudged off its square by a fixed random amount, so the plate looks scattered by hand rather than printed.
• Idle drift: When your mouse leaves the page, the cursor magnet wanders in a slow loop around the centre instead of stopping.

One fragment shader draws the whole plate: for every pixel it checks the nine nearest filings, works out the field from all three magnets at each filing, and draws that filing as a short smooth-edged line.

What it reacts to

• Mouse: The nearest magnet slides after your cursor, catching up in about half a second, so the filings swing round behind it as it moves.
• Music: With music sync on, bass makes all three magnets up to 90 percent stronger, so the filings brighten and lengthen; a sudden kick makes every filing shiver on its axis for a moment.
• Night: In Auto mode an indigo veil fades in around sunset and lifts around sunrise; the Day/Night button in the Themes panel can force either.

Free or Pro?Pro

Ambient New Tab is free to install, with five free themes. Magnetic Dipoles is a Pro theme. Pro is $5.99 a month or $39.99 a year, cancel anytime, or $59 once for Pro Forever, and it unlocks every Pro theme, music sync, and every new theme as we release it. You can preview Magnetic Dipoles full screen before you buy: open the Themes panel and rest your mouse on it. Changed your mind? 14-day refund, no questions.

How to get it

1. Add Ambient New Tab to Chrome.
2. Open a new tab and click the Themes pill in the bottom-right corner.
3. Pick Magnetic Dipoles. Done.

Questions

Is the magnetic field physically correct?

Yes, for a flat plate. Each filing points along the sum of the standard dipole field, B = (3(m·r̂)r̂ − m) / r³, from the three magnets. Very close to each magnet the distance is softened by about two filing spacings so the field does not shoot to infinity at the pole.

Is Magnetic Dipoles free?

It is a Pro theme. Pro is $5.99 a month or $39.99 a year, cancel anytime, or $59 once for Pro Forever. It unlocks every Pro theme, music sync, and every new theme as it is released.

Why does the cursor magnet lag behind my mouse?

It eases toward the cursor rather than snapping to it, closing most of the gap in about half a second. That delay lets you watch the filings re-align in a wave behind the magnet, much as real filings shuffle into place when you slide a magnet under the paper.

Why do the red and blue tips turn?

Every magnet spins slowly while it moves. The two wanderers turn in opposite directions, roughly one full turn every 18 to 25 seconds, and your cursor magnet turns more slowly still. As the poles rotate, the field lines between them flip from tight loops to long open arcs and back.

Does it work on my phone?

No. It's a desktop browser extension for Chrome on Windows, macOS, Linux and ChromeOS. If you're reading this on a phone, send yourself the link.

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