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A printable worksheet for the lesson Delivery: from asteroid families to Earth (Start here: Expert). It prints on A4 without the website around it. The answers are on a separate sheet for the teacher.

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Delivery: from asteroid families to Earth

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Key words

Meteorite
A meteorite is a piece of space rock that has survived its fall through the air and landed on Earth.
Astronomical unit
An astronomical unit is the average distance from Earth to the Sun, about 149.6 million kilometres.
Kirkwood gaps
Narrow zones in the main asteroid belt with very few asteroids, cleared by orbital resonances with Jupiter.
S-type asteroid
An S-type asteroid is a stony asteroid of moderate brightness, the kind that supplies most ordinary chondrites.
Chondrite
A chondrite is a stony meteorite full of tiny round grains called chondrules, and almost unchanged since the Solar System formed.
Chromite
A hard, black iron-chromium oxide mineral found in most stony meteorites and remarkably resistant to weathering.

Choose the right answer

Circle the letter of the right answer.

  1. What do the samples from Ryugu and Bennu resemble?
    • ALL ordinary chondrites
    • BCI carbonaceous chondrites
    • CEnstatite chondrites
    • DEucrites from Vesta
  2. What is the Yarkovsky effect?
    • AA gravitational kick from a passing major planet
    • BOrbital change caused by repeated collisions
    • COrbital drift caused by uneven thermal emission
    • DPressure from the solar wind on fine dust grains
  3. Why do argon-argon ages of shocked L chondrites support the break-up event?
    • AThey show that the L parent body is still intact today
    • BThey show that L chondrites first formed 470 Myr ago
    • CThey match the ages of the limestone itself
    • DThey cluster near 470 Myr, when shock reset them
  4. What makes the fossil meteorite Österplana 065 notable?
    • AIt is the only iron in the limestone
    • BIt matches no known meteorite group
    • CIt fell during a recorded Ordovician storm
    • DIt is the oldest L chondrite ever found
  5. Why are the Kirkwood gaps nearly empty of asteroids?
    • AResonances with Jupiter remove asteroids
    • BCollisions there are far more frequent
    • CMars's gravity pulls the asteroids out
    • DSunlight there is strong enough to vaporise them

True or false?

Is the answer given right? Tick True or False.

  1. Which approaches did the 2024 studies of ordinary chondrite sources combine?

    Answer given: Dynamical modelling and spectroscopy TrueFalse

  2. In 2024, which asteroid families were proposed as the main sources of H chondrites?

    Answer given: Koronis and Karin TrueFalse

Write your answer

Answer in a word or a short sentence.

  1. What caused the Ordovician increase in L chondrite delivery?
  2. About how long ago did the mid-Ordovician surge in L chondrite material begin?
  3. What have studies of extraterrestrial chromite in older sediments found?

Task

Plot the cosmic-ray exposure ages of H chondrites as a histogram using values from published compilations. Note the peak around 7 to 8 million years and consider what kind of event could produce it.

Howardites · free to copy for use in your classroom · answers are on the separate teacher's answer sheet