Travel in time. The planets no longer just drift forward. The speed slider now has a stop in the middle: push it right to run the solar system forward, pull it left to run it backward, and the further you go the faster time moves. Stop at the center and tap the date to jump anywhere between 1800 and 2050. And the positions are now real. Every planet is placed using NASA JPL's orbital elements, so the arrangement you see on any date is the arrangement the sky actually had. Orbits are true ellipses, so the planets speed up near the sun and slow down far from it, and Pluto's path visibly dips inside Neptune's, exactly as it did between 1979 and 1999. Find the day you were born. Watch the planets line up. Then run it backward and watch it come apart.

The Grand Orrery is now built for iPad and Mac. On iPad, the whole solar system fills the screen in both portrait and landscape, with type and controls scaled for the larger canvas — and the worlds now render at higher resolution, so close-ups of Mercury, the Moon and the outer moons stay crisp. On Mac, the app runs in its own resizable window with full-screen support, a proper menu bar, and keyboard shortcuts — press Space to pause, the arrow keys to change speed, and O, L or T to toggle orbits, labels or the Grand Tour. Scroll to zoom in and out. One purchase covers iPhone, iPad and Mac.

Fixes the speed control disappearing behind a world's card in portrait. The play/pause and rate slider now stay on screen while you read, so you can speed up or slow down the system without closing the card first. (Thank you to the user who wrote in about the slider.) Closing a card is smoother too: the world now glides back to centre with the same camera move that brought you in, instead of snapping.