SpaceSim is a free browser-based Solar System explorer. Travel continuously between source-attributed 3D views of the Sun, Mercury, Venus, Earth, the Moon, Mars, Jupiter, Saturn, Uranus, and Neptune, change simulated time, and pull back into a real-scale Solar System atlas with checkable scientific state for every world.
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Keyboard controls: use the arrow keys to orbit and Page Up and Page Down to change distance. Escape opens the Atlas through a short continuous journey, or returns to the current world. Moving the pointer or pressing a key reveals contextual controls. Reduced motion presents the journey as user-advanced steps.
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The destination preview is generated promotional artwork, not scientific evidence.
Before there were planets, oceans, or memory, there was the Sun. A star of plasma, it holds nearly all the mass in our Solar System, and its light powers almost every living thing we know.
Mercury keeps two kinds of time: a year of 88 Earth days, and a solar day twice as long. With almost no atmosphere, its surface swings from furnace to freezer, yet ancient ice survives in craters where sunlight never reaches.
Venus looks serene from Earth, but beneath its clouds lies a furnace. Carbon dioxide traps heat until the surface is hotter than Mercury's, while crushing pressure turns our near-twin into a warning about worlds that diverge.
Seen from the dark, Earth's borders disappear. Weather moves over water, cities kindle on the night side, and a magnetic field helps shield the atmosphere. It is the only world known to be alive.
The Moon is ancient stone: bright highlands, dark lava plains, and craters that remember impacts Earth has forgotten. It turns once per orbit, keeping nearly the same face toward us, while its gravity raises our ocean tides.
Mars once held rivers and lakes. Its organic molecules are not proof of life, and no discovery has shown that Mars was inhabited. If life survives there today, underground refuges may be its safest shelter.
Jupiter is gravity made visible: a world of hydrogen and helium, turning in about ten hours. Its swift rotation bands the clouds and drives storms larger than Earth, while its moons form a system of their own.
Saturn's rings are a bright architecture of ice and dust, each particle circling alone. The planet itself is mostly hydrogen and helium, light enough that its average density is less than water.
Uranus rolls around the Sun on its side, likely after an ancient collision. Methane gives its atmosphere a blue-green tint, and its extreme tilt turns each season into a decades-long experiment in light.
Neptune is a blue world at the edge of the known planets, driven by winds faster than any on Earth. It receives little sunlight, yet its atmosphere remains fiercely active. Distance does not mean stillness.
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