Phenomenon
Investigation Driving Question
How can we determine if an asteroid is a threat to Earth?
Storylines
The storyline process is intended to be student-driven and connect lessons within the unit. The Hazardous Asteroids investigation, including this phenomenon, would fit best into unit storylines focused on natural hazards and Solar System dynamics.
Possible storylines include:
What is the difference between a near-Earth Object and a potentially hazardous asteroid?
Why is it important to continuously monitor known asteroids?
Can we predict if an asteroid is likely to impact Earth?
What changes could an asteroid impact bring about in climate and habitability?
Instructions for Introducing Phenomenon
- Before class starts, arrange a Driving Question Board (DQB) so it is visible to all students. This can be created using sticky notes or in a digital format (see other resources here). The DQB should include the investigation driving question, “How can we determine if an asteroid is a threat to Earth?” Students will be revisiting this DQB throughout the lesson. If you have a driving question for the unit or already created a DQB board, this investigation driving question can be used as a sub-question.
- Have students read and think about the driving question before doing the activity. (3 minutes)
- To engage students in asteroids and their discovery, provide students with the video, A Swarm of New Asteroids (for teacher background – this webpage breaks down the video).
- Replay the video starting at 28 seconds to focus on the near-Earth Objects (NEOs) discovered, shown in yellow-orange. Note: in order to make it easier to spot the NEOs, you can adjust the playback speed on YouTube by slowing the motion.
- Share with students, “Rubin Observatory will uncover many NEOs, most of them asteroids and some comets — and a few could potentially be on a collision course with Earth. Rubin Observatory will uncover a few million previously unseen asteroids, including about 89,000 NEOs that have yet to be detected. By dramatically increasing discovery rates, Rubin will give scientists the earliest possible warning of any potential impact threats.
4. Next, provide students with Rubin’s Orbitviewer App, which highlights Rubin’s discoveries and visualizes the dynamic Solar System in 3D.
5. Have students make aT-Chart in their notebooks, with the left side labeled "Notice" and the right side labeled "Wonder." Ask students to use Orbitviewer, paying attention to NEOs (purple), and to record what they notice. (Optional - students could record their notice and wonder during the asteroid video and add to their chart after exploring Orbitviewer.)
6. Have students continue exploring NEOs and record their wonderings (or questions).
7. When students have completed their wonderings, place them in small groups to share their noticings and wonderings. As a group, they should work together to select their top three questions about asteroids to share with the whole class. To help students determine which questions to select, encourage them to reread the driving question and see whether any of their questions would help to figure it out.
8. Gather the class’s wonderings by asking a group to share one of their questions. After a question has been shared, ask the class if any other group had a similar question. Group similar questions together on the DQB. Some questions may be different than any other and be placed alone on the DQB. (10 minutes)
9. As a whole class, facilitate a discussion about the questions. Begin by identifying and grouping common questions into categories. (10 minutes)
10. Revisit the investigation driving question and tell students they will be completing an investigation that will help them answer this driving question and their generated questions about asteroids.
11. Begin the Hazardous Asteroids Investigation
Checkpoints - Revisiting the Phenomenon
Checkpoint 1 (End of p.8)
Draw a model in your notebook to demonstrate what makes Bennu look risky, and another model to show what makes it actually not risky. Use the investigation or Rubin’s Orbitviewer App as a reference.
Student models should include a top-down view of Bennu showing that the orbits of Bennu and Earth actually cross. The side-view model should show that Bennu’s orbit is inclined ~6° from Earth’s orbit, meaning Bennu is typically above or below Earth. The side-view model could show the intersection points, but both objects are not at the intersection at the same time. They could illustrate this by plotting one of the objects at the intersection point and one somewhere else along its orbit.
As a whole class, revisit the DQB to see if you can now answer any of the questions, or add new questions
Checkpoint 2 (End of p.17)
Bennu will have a very close approach to Earth on 24 September 2135 and again in 2182. The 2182 flyby has a 0.037% chance of impact. Draw a model and describe what could cause Bennu’s chance of impact in 2182 to change.
See NASA visualizations depicting this flyby to share with students after they draw their models. Bennus’s chance of Earth impact may increase or decrease depending on its close approach in 2135 due to its gravitational interaction with the planet.
As a whole class, revisit the DQB to see if you can now answer any of the questions, or add new questions.
After the Investigation - Making Sense of the Phenomenon
Explain why Bennu’s orbit should continue to be monitored using what you have learned about PHA’s, impact probability, and gravitational interactions.
Bennu’s orbit should continue to be monitored because its MOID is less than 0.05 and its diameter is larger than 140m, making it a PHA. Bennu’s close approach in 2135 could increase the probability of an Earth impact in 2182, as its trajectory may change due to Earth’s gravity.
As a whole class, revisit the DQB to see if you can now answer any of the questions, or add new questions.