Vol. Science · Astronomy · Interactive map

Solar system
map

A clickable schematic of our neighborhood — Sun through Neptune, with Pluto labeled as a dwarf planet. It opens in 3D (drag to orbit; the flat map is the 2D control). Set a day and local time (defaults to now) and the planets move to approximate positions for that moment. Play walks the date forward; set the speed from one hour per second up to ten years per second. Also see the Moon phases dial, why that same face still shows past the limb (libration — a locked spin, eccentricity 0.0549, and a lunar equator tilted 6.68° to its orbit), why eclipses are rare (the Moon’s orbit is tilted about 5°, so most new and full Moons miss), why most shores on a smooth-Earth cartoon see about two high tides a day (spring when the Sun lines up, neap at the quarters), and why the year has seasons (axial tilt, not distance), why sunrise and the three twilights fall where they do (twilight — astronomical dawn at −18°, nautical at −12°, civil at −6°, sunrise at the standard −0.833°, from NOAA’s solar calculator), why a star near the horizon is dimmer and lifted (airmass — Kasten and Young, Table II 38.0868 at the horizon, Bennett about 34′), why that axis slowly walks a cone so the pole star changes (precession — about 26,000 years, and the tropical year is shorter than the sidereal year), why the noon Sun traces a figure-8 (analemma — declination and the equation of time), why a sidereal day is shorter than the mean solar day (sidereal — the stars gain about four minutes a night), why new Moon to new Moon outlasts one orbit of the Moon (synodic month — the Moon is back among the stars and the Sun has moved on), why Mars can seem to back up (retrograde — Earth overtaking on a faster inner orbit, not a reversed path), why an outer planet stands opposite the Sun at opposition (Earth between the Sun and Mars — the bright geometry, not a reversed orbit), why a larger orbit takes longer (Kepler — for a circular orbit around the Sun, P² = a³ when P is in years and a is in AU), why a circular orbit is slower than escape by √2 (escape — orbital speed and escape speed at one altitude, Newton’s cannon as a schematic), why the cheap path between two circular orbits is half an ellipse (Hohmann — two impulsive burns, fact-sheet distances, Earth to Mars in 258.88 days), why speed anywhere on one ellipse is vis-viva (v = √[μ (2/r − 1/a)], Earth’s perihelion 30.29 km/s and aphelion 29.29 km/s), why an Earth satellite’s period, speed, ground track, and horizon follow from altitude (satellites — the cited 420 km station circle is 92.97 min, and geostationary is 35,786.05 km), why that ellipse is stretched by eccentricity (r_p = a(1−e) and r_a = a(1+e); Earth’s e is 0.0167, Mercury’s is 0.2056, Halley’s is 0.967, and periapsis is faster), why the same impulsive Δv buys more energy deep in a well (Oberth — Δε = v·Δv + ½(Δv)², and escape from a circle still costs v_c(√2 − 1)), why that Δv costs propellant (rocket equation — Δv = v_e · ln(m₀/m_f), ideal, constant exhaust speed, no gravity losses and no drag), why a flyby can raise or lower heliocentric speed without a burn (gravity assist — an unpowered hyperbola turns v∞ while the planet keeps moving; a classroom Earth pass at 5 km/s and 400 km turns 89.16° and the heliocentric change is 7.019 km/s), why a hyperbolic departure is counted as characteristic energy (C3 — C3 = v∞²; at 400 km, C3 = 0 is a 3.178 km/s burn and a classroom v∞ of 3 km/s is C3 = 9 km²/s², a 3.585 km/s burn), why five points keep a fixed pattern in the rotating frame (Lagrange — L1 through L5, a Hill approximation beside the numerical collinear root, Sun–Earth L2 at 1,501,538 km from Earth), why a moon inside a critical distance cannot hold together (Roche — a fluid limit and a rigid one, Rhea outside, the Moon far outside, Phobos between them), why a secondary carries a sphere of influence (Hill — r_H ≈ a (m/(3M))^(1/3), Earth’s sphere 1,496,565 km with the Moon inside it, Jupiter’s 53,147,220 km, Phobos deep inside Mars’s), why the Moon and the Sun can share a size (angular size — δ = 2·arctan(d / 2D), a mean-perigee Moon is 32.880′ and can cover the Sun, an apogee Moon is 29.458′ and leaves a ring), and what an aperture and an eyepiece decide (telescope optics — focal ratio, magnification, exit pupil, Rayleigh’s 1.22 λ/D, and Dawes’s 116/D), why Venus shows phases (Venus — an orbit inside Earth’s, crescent through gibbous, not a moon), why the other planets do not all do that (planet phases — Mercury’s crescent, Mars’s gibbous disk, Jupiter from Earth and from a spacecraft; a page each for Mercury, ratio 0.387, Mars, ratio 1.524, Jupiter, ratio 5.204, Saturn, ratio 9.573, Uranus, ratio 19.165, and Neptune, ratio 30.178), then continue with the local sky (city or ZIP, default Campbell), a stars types & lives color lesson, stellar magnitude (apparent m, absolute M, and why five magnitudes is a factor of 100), a meteor shower rate (HR = ZHR × sin(h) / r^(6.5 − LM) × (1 − cloud); the IMO row at 30° is 50; not a forecast), an impact scaling (diameter, density, speed, and angle; Collins et al. 2005 transient and final crater diameters; not a hazard assessment), an HR diagram (effective temperature versus luminosity, hot on the left, with a schematic main sequence, giants, and white dwarfs), stellar lifetime (mass, the Eker et al. 2018 mass–luminosity fit, and t ≈ 10 Gyr × M/L), black holes (Schwarzschild radius, photon sphere, and ISCO for a non-spinning hole; the nominal solar mass is 2.953 km), redshift (z = (λ_obs − λ_rest)/λ_rest; at z = 1 the relativistic β is 0.6; Hubble’s law only nearby), nearest stars, the parallax yardstick that turns Earth’s orbital shift into a parsec, the distance ladder (modulus with extinction, Cepheids, Type Ia, and cz/H₀), a cosmology calculator (age, lookback time, and the cosmological distances), exoplanets, the transit and radial-velocity numbers (depth, duration, and K), a habitable zone (stellar flux, equilibrium temperature, and the Kopparapu et al. 2014 limits), and a Milky Way starter. Light itself — radio through gamma — has a literacy desk at EM spectrum. The force that schedules this map has its own literacy desk: Gravity. Part of the science desk; also see Earth’s atmosphere.

Educational schematic. The 3D view uses NASA JPL approximate Keplerian elements (eccentricity and inclination) for the eight planets. Pluto uses the same style of fit. Distances can be log-compressed or true to the AU. Planet sizes are exaggerated in both views so the bodies stay visible. Moon gaps, when shown, are stretched. The 2D control keeps the original flat map: circular orbits and approximate mean heliocentric longitudes. Not a JPL Horizons ephemeris. Periods and mean distances follow NASA NSSDCA fact sheets.

3D · log-compressed distances · inclinations kept · sizes exaggerated.

WebGL is unavailable in this browser, so the flat map is shown.

Astronomy desk