Real Star Systems

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 2056.1 Hz, 769 cents sharp of E6, the nearest tine on the comb. The next fifteen are its overtones, and each one draws its own figure: sand gathers on the lines that stay still.

Tap to see it edge on, as from Earth. Pick a system, speed and spacing in the Splash tab.

Real planets round other stars, from the NASA Exoplanet Archive: TRAPPIST-1, a cool red dwarf 40 light-years away with seven rocky planets, all closer to it than Mercury is to the Sun; TOI-178, whose six planets go round in a chain of near-simple ratios; and 55 Cancri, with a planet whose year is shorter than a day. The inner Solar System is there to compare.

The orbits' sizes and periods are measured, and the planets move at those rates, sped up. Star and planets are drawn far larger than to scale. Nobody knows these planets' colors, so they show their size: gray-brown for rocky, blue for mid-sized, tan for giants. Tap to see the system edge on, as we see TRAPPIST-1 and TOI-178: their planets were found as they passed in front of their stars.

Real planetary systems from the NASA Exoplanet Archive: each planet's orbit size and period are the archive's, and the planets go round at those rates, sped up as labeled. The star's and the planets' sizes are enlarged and their colors unknown, and the splash says both.

1. Correct

   The planets' orbit sizes, periods and radii are the NASA Exoplanet Archive's composite values.¹

   tools/sp2-systems.mjs reads them from the archive's Planetary Systems Composite Parameters table through its TAP service.

2. Correct

   Each planet goes once round its star in its measured period (sped up by the chosen factor).²

   The drive adds the elapsed days over each planet's period to its angle; the test checks the angles after 12 days.

1. 1NASA Science Data License, NASA
2. 2Planetary Systems table columns, NASA Exoplanet Archive

Simplified

The star and the planets are drawn far larger than the orbits' scale (said in the splash).

Simplified

Orbits are drawn as circles in one plane; the real ones are very slightly oval and tilted a little to each other.

Simplified

The planets' colors are not known; they are colored by size class (said in the splash).

Simplified

Each planet starts at an arbitrary place on its orbit, not where it is today.

Simplified

Spread out (not to scale) places the orbits by the square root of their sizes.

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