Asteroids Overview Quiz

Asteroids

• Definition: Fragments of rock left over from solar system formation.
• Discovery: First asteroid discovered in 1801 by Giuseppe Piazzi.
• Number: Over one million identified.
• Size: Ranges from less than 1 km to hundreds of km wide.
• Composition: Rocky material; varying shapes with craters.
• Ceres: Largest asteroid (considered a dwarf planet), 1,000 km in diameter; spherical shape.
• Types:
  • C-type (chondrite): Most common; clay and silicate rocks; dark color.
  • S-type (stony): Nickel-iron and silicate; somewhat bright.
  • M-type (metallic): Nickel-iron; bright; some have volcanic lava.
• Origin: Leftover rock fragments from solar system formation.
• Location: Primarily found in the asteroid belt between Mars and Jupiter (believed formed from colliding planetary bodies due to Jupiter's gravity).
• Trojans: Asteroids that orbit planets.
• Near-Earth: Asteroids that sometimes approach or enter Earth's orbit.
• Orbit: Elliptical; mostly between Mars and Jupiter; some can be pulled toward a larger body during orbit.

Meteors

• Definition: Rocks from space entering Earth's atmosphere.
• Appearance: Burn up and produce fireballs (shooting stars).
• Size: Range from dust speck to asteroid size.
• Composition: Rocks, metal, or a combination.
• Meteorites: Meteors that survive atmospheric entry and reach the ground; can have a burned, metallic outer layer.
• Origin: Pieces broken off larger bodies (asteroids, comets), or other planets/moon.
• Meteor Showers: Meteors from comet debris; occur when Earth passes through a comet's debris trail.
• Meteoroid: A meteor in space (before entering the atmosphere).
• Meteor: A meteoroid burning up in the atmosphere.

Comets

• Definition: Remnants from solar system formation; made of dust, rock, and ice.
• Characteristics: As they approach the sun, they heat up and release gases, forming a glowing head (coma) and a trailing tail of material.
• Visibility: Can be visible for days or weeks when passing near Earth.
• Historical Significance: Sometimes seen as bad omens.
• Size: A few miles to tens of miles wide.
• Comets Closer to the Sun: When near the sun, their head can grow planet-sized, and the tail can stretch millions of miles.
• Composition: Nucleus (center) of frozen gases; coma (atmosphere) created when gases are released.
• Origin: Mostly the Oort Cloud (a large cloud of ice and dust).
• Types:
  • Long-period: Orbit the sun in over 200 years; from the Oort Cloud.
  • Short-period: Orbit the sun in less than 200 years; from the Kuiper Belt (disk-shaped region outside Neptune's orbit).

Differences Between Asteroids, Meteors, & Comets

• Asteroids vs. Comets: Asteroids are primarily rock & metal, while comets contain rock, ice, and dust. Comets have a "coma" and tail, asteroids typically do not.
• Asteroids vs. Meteors: Asteroids are large, orbiting bodies; meteors are smaller rocks/space-debris entering the atmosphere.
• Meteors vs. Comets: Meteors burn up in the atmosphere, comets are largely frozen celestial bodies until they encounter the sun. Comet debris can form meteors if Earth crosses the debris path.
• Impact on Earth: Meteor impacts are generally minor, while asteroid/comet impacts can cause major damage, potentially leading to mass extinctions (depending on object size & composition).