Asteroids, Comets and Meteors
Identify other objects in the solar system beyond planets: asteroids (rocky bodies mostly between Mars and Jupiter), comets (icy bodies with tails when near the Sun), and meteoroids/meteors/meteorites (space rocks that enter Earth's atmosphere)
What a learner can do afterwards
- Describe asteroids as rocky bodies mostly found in the belt between Mars and Jupiter
- Describe comets as icy bodies that develop a glowing tail when they approach the Sun
- Explain the difference between a meteoroid (in space), meteor (streak of light in atmosphere), and meteorite (lands on Earth)
1 · Read
You already know the eight planets orbit the Sun. Space also has smaller objects called asteroids. Asteroids are chunks of rock and metal. Most of them travel in a wide belt between Mars and Jupiter.
One night, Alex sees a quick streak of light zoom across the sky. That is a meteor, a tiny space rock burning up as it rushes through our air. If a piece survives and lands, it becomes a meteorite.
Comets are different from asteroids. A comet is made of ice, dust, and frozen gas, like a dirty snowball. When it gets close to the Sun, the heat turns some of that ice into gas and dust, which stream out and form a long glowing tail.
Asteroids are rocky bodies mostly between Mars and Jupiter, comets are icy bodies that grow a tail near the Sun, and a shooting star is really a meteor, a space rock burning up in the sky.
More to read
13.1 Asteroids
Asteroids are rocky leftovers from when the solar system formed. Most orbit the Sun in a belt between Mars and Jupiter. They range from tiny pebbles to Ceres, which is about 940 km across and is also a dwarf planet. Asteroids have irregular shapes because they are too small for gravity to pull them into spheres. Spacecraft have visited several asteroids and found they are made of rock and metal, some with water-bearing minerals.
13.4 The Origin and Fate of Comets and Related Objects
Comets are dirty snowballs: ice, dust, and rock mixed together. They come from two cold regions far beyond Neptune: the Kuiper Belt and the Oort Cloud. When a comet gets close to the Sun, the ice turns to gas and forms a glowing head and a long tail that can stretch millions of kilometres. The tail always points away from the Sun because solar wind pushes it. Some comets return regularly, like Halley's Comet every 76 years.
Solar System Glossary
Meteoroids are small rocky or metallic bits in space. When one hits Earth's atmosphere, it burns up and makes a streak of light called a meteor or shooting star. If any piece survives and lands on the ground, it is a meteorite. Dwarf planets like Pluto, Eris, and Ceres are round like planets but have not cleared their orbits of other debris. They share their neighbourhood with many similar objects.
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Where it sits
Learn first
Nothing; this is a starting point.
Optional connections
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Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.