The real universe

Estelar Online’s universe is built only from real data. Every star is where astronomers measured it, every planet outside the Solar System is a confirmed exoplanet, and the distances are the real ones: a kilometer in the game is a kilometer. No made-up systems or planets to fill the map.

Where the data comes from

Source	What it gives the game
HYG Catalog v4.1 (David Nash, astronexus, CC BY-SA 4.0 license)	The stars: position, brightness, spectral class, temperature, radius and name.
NASA Exoplanet Archive (Caltech, for NASA)	Confirmed planets around other stars: radius, mass, density, temperature, orbit, year and discovery method.
JPL orbital elements	The positions of the Solar System planets.
Solar System Scope (CC BY 4.0 license)	The textures of the Solar System planets.

The game’s catalog has 112,144 stars and 6,338 exoplanets in 4,199 systems with confirmed planets. It’s complete out to about 250 light-years from the Sun; beyond that, only the brightest stars, out to about 10,000 light-years.

Real scale

Everything is at true scale. A light-year is 9.46 trillion kilometers, and the game uses that math: Earth is one astronomical unit (about 150 million km) from the Sun, and Proxima Centauri is 4.2 light-years away. Speed is shown in km/s and distances in km, AU or light-years, depending on size.

To cross those distances there’s warp:

In-system warp: goes to the target and brakes on its own. From Aurora Station to Mars takes about half a minute.
Interstellar warp: to another star, up to 1 million times the speed of light. The neighboring star is about 3 minutes away. It charges 10 fuel on departure, on top of the normal warp burn.

Physics is real wherever you can feel it, too: near a planet or moon, a stopped ship has to push against gravity, and the positioning thrusters in the FLIGHT panel get used up. With no reserve, the ship falls with the acceleration that body’s gravity dictates.

Sectors

Space is divided into sectors, cubes 4 light-years on a side. The SYSTEM panel shows the sector you’re in (for example, SECTOR 0 · 0 · 0, the Sun’s) and your position relative to its star.

One system per sector. When a sector has more than one catalog star, the one with confirmed planets becomes the system; among equals, the brightest. The others stay in the sky.
One kiosk per sector, even in empty space: a safe spot every 3 minutes of warp or so. See Stations and kiosks.
Pirate level rises with distance from the Sun: near home they’re weak; level 100 is around 250 light-years out. See Pirates and spots.

The sky

The background sky draws every star in the catalog in its true direction, with the apparent brightness from where you are. As you travel, the constellations distort the way they really would, and the Sun becomes just another star.

The star map ([M] by default), in the NEARBY SYSTEMS tab, lists the stars closest to you, with the type and number of planets of each.

The Solar System

The game starts at the Sun, the only system built by hand:

The eight planets in their real positions on September 25, 2026, the date of the game’s universe, calculated from JPL orbital elements. The universe stays frozen on that date, so every pilot sees the planets in the same place.
Real rotation: on screen, the planets spin at their true speed, which means almost not at all.
Real moons, with true radius and distance: the Moon (at its real position for the date), Phobos and Deimos, Io, Europa, Ganymede and Callisto, Enceladus, Rhea and Titan, Ariel, Titania and Oberon, Triton and Nereid.
Two belts with asteroid fields to mine: the Main Belt, at 2.7 AU, and the Kuiper Belt, at 42 AU.
Two stations orbiting Earth: Aurora Station, where every pilot starts, and Sol Arena, the home of matches.

Exoplanets

The planets of other stars come from the NASA archive. The game classifies each one by radius, mass and equilibrium temperature: hot Jupiter, gas giant, sub-Neptune, super-Earth, rocky planet in the habitable zone, lava world, icy world and so on.

What science doesn’t know yet, the game doesn’t make up:

Data missing from the catalog (radius, mass, temperature or orbit) is estimated from physical relationships and shows with a “~” in the record, so it isn’t passed off as measured.
The planet’s position in its orbit around other stars is unknown for most of them: they all sit at a conventional position, and the record says so.
No rings, tilt or moons on exoplanets: no exomoon has been confirmed.
Only the Solar System has asteroid fields: no belt has been observed around other stars.
Stars without confirmed planets are star-only systems. Some have a station orbiting the star itself.

Planet colors are the only free part: the catalog doesn’t say what color an exoplanet is.