Stars, Planets, and the Solar System
Look up on a clear night. Every point of light is a STAR, a PLANET, or something farther. Our own solar system has ONE STAR (the Sun) and EIGHT PLANETS orbiting it. Plus dozens of moons, thousands of asteroids, and comets. Today you'll learn the cosmic neighborhood.
The Sun — Our Star
The Sun is a STAR — a giant ball of glowing gas that fuels our solar system.\n\n- About 4.6 billion years old\n- 109 times wider than Earth\n- Contains 99.8% of all mass in the solar system\n- Gravity holds all the planets in orbit\n- Provides light and heat to Earth\n- Will keep shining for another ~5 billion years\n\nWithout the Sun, there would be NO life on Earth.
The 8 Planets
In order from the Sun:\n\n1. **MERCURY** — smallest, closest to Sun, super hot days and freezing nights\n2. **VENUS** — hottest planet (thick greenhouse atmosphere), spins backward\n3. **EARTH** — the one with life!\n4. **MARS** — "the Red Planet," smaller than Earth, has polar ice caps\n5. **JUPITER** — biggest planet, Great Red Spot is a 400-year-old storm\n6. **SATURN** — stunning rings made of ice and rock\n7. **URANUS** — tilted sideways; spins on its side\n8. **NEPTUNE** — windiest; winds up to 1,200 mph\n\nMemory trick: **M**y **V**ery **E**ducated **M**other **J**ust **S**erved **U**s **N**achos
Which planet is CLOSEST to the Sun?
Rocky vs. Gas Planets
The planets split into two groups:\n\n**INNER (rocky)**: Mercury, Venus, Earth, Mars. Small, solid surfaces. Closer to the Sun.\n\n**OUTER (gas giants)**: Jupiter, Saturn, Uranus, Neptune. Huge, mostly gas and ice. Far from the Sun.\n\nBetween them is the ASTEROID BELT — millions of space rocks.
Moons
A MOON orbits a planet (not the Sun).\n\n- **Earth**: 1 moon\n- **Mars**: 2 tiny moons (Phobos, Deimos)\n- **Jupiter**: 95 known moons! (Io, Europa, Ganymede, Callisto)\n- **Saturn**: 146 moons (Titan is bigger than Mercury)\n- **Uranus**: 27 moons\n- **Neptune**: 16 moons\n\nEurope (Jupiter's moon) might have an ocean under its ice — scientists think it could support alien life!
Asteroids and Comets
**ASTEROIDS** — rocky objects, mostly between Mars and Jupiter (the Asteroid Belt). Leftover from solar system formation.\n\n**COMETS** — icy objects with long elliptical orbits. As they near the Sun, ice vaporizes making a spectacular TAIL. Halley's Comet returns every 76 years (last: 1986; next: 2061).\n\n**METEORS** — space rocks that burn up in Earth's atmosphere. What you see as shooting stars!
Which planet has the MOST MOONS?
Build a Solar System Model
Use balls or fruits for planets, scaled roughly by size:\n\n- Sun: beach ball\n- Jupiter: orange\n- Earth: pea\n- Mars: grape\n- Mercury: tiny bead\n\n1. Lay them out in order.\n2. If the Sun is 1 foot away, Earth should be... WAY farther than you'd think.\n3. Space is HUGE.\n4. Take a photo of your model.
Star Gaze
1. On a clear night, go outside with a parent.\n2. Look up.\n3. See if you can spot a PLANET (check online — "planets visible tonight").\n4. Planets don't twinkle like stars!\n5. Use a free app like SkyView to identify what you see.\n6. That's real cosmology — and you just did it.
What mostly makes up the OUTER planets (Jupiter, Saturn, etc.)?
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