天文
月球、恒星与更远处
你要讲的内容 · 先选年级
3 年级共 5 个知识点
The Solar SystemThe Sun's family — eight planets, their moons, and lots of smaller stuff, all circling one star in the middle.开讲 →The Rocky PlanetsMercury, Venus, Earth, and Mars — the four small, rocky planets closest to the Sun, and what makes each one special.开讲 →The Gas GiantsJupiter, Saturn, Uranus, and Neptune — giant faraway planets made mostly of gas and ice, including Saturn with its dazzling rings.开讲 →Moons Around Other PlanetsEarth has one moon, but Jupiter and Saturn have dozens — a moon is anything that orbits a planet instead of the Sun.开讲 →Planets and Dwarf PlanetsThe three rules an object must pass to count as a planet — and why little Pluto got reclassified as a dwarf planet.开讲 →
往后的路 · 年级阶梯
Pick a grade · difficulty climbs 1 → 12
天文 across the grades
Grade 6Middle school
Solar System in depth · comets, asteroids, eclipses