WEEK 11 - Modern Doomsday Scenarios Flashcards
What is the purpose of disaster movies?
- Designed to entertain, but based on possible global catastrophe scenarios.
- Stretch the truth for dramatic effect.
How do disaster movies raise public awareness?
- Highlight potential global disasters, increasing public awareness of these threats.
- Often based on real scientific scenarios, despite exaggerated elements.
What is the connection between disaster movies and real global catastrophe scenarios?
- Many scenarios in disaster movies are grounded in scientific possibilities, like asteroid impacts, global warming, or pandemics.
- While exaggerated, they reflect real-world concerns.
Two Disaster Films
- Deep Impact
- Armageddon
How do “Deep Impact” and “Armageddon” compare?
Premise: Both involve a large object (comet/asteroid) hurtling toward Earth, threatening a global catastrophe.
Differences:
- Deep Impact: The threat is a comet.
- Armageddon: The threat is an asteroid.
Common Message: Both movies emphasize the real threat of an impact event.
How real is the threat of bolide impact?
Past Evidence:
- Sudbury Basin (1.85 billion years ago)
- Chicxulub Crater (65 million years ago, linked to dinosaur extinction)
Modern Examples:
- While there have been no major impacts recently, the threat is always present.
- The Earth is still vulnerable to potential impact events in the future.
Tunguska Event (1908)
Event: Explosion over Siberia on June 30, 1908, at 7:17 AM.
Cause: Likely caused by the airburst of a comet or asteroid.
Impact: Not large enough to affect global population but demonstrated the possibility of impact events.
Significance: Highlights the threat of large objects impacting Earth, even in modern times.
Tunguska Event: Seismic Recordings
Seismic vibrations recorded up to 1000 km away from the explosion
Tunguska Event: Observers’ Reports
- “Deafening bangs” heard 400-500 km away from the explosion.
- A fiery cloud seen on the horizon, 400 km southeast of the explosion.
What Happened 200 km from the Tunguska Explosion?
- The object appeared as a brilliant, sunlike fireball.
- Thunderous noises were heard in this area.
What Happened 60 km from the Tunguska Explosion?
- People were thrown to the ground or knocked unconscious.
- Windows were broken.
- Crockery was knocked off shelves.
What Happened to the Closest Observers of the Tunguska Event?
- Reindeer herders about 30 km from the site were blown into the air and knocked unconscious.
- One man was killed when he was blown into a tree.
What Did the Expedition to the Tunguska Impact Site Find?
- In 1930, Professor Leonid Kulik’s expedition found immense devastation.
- Within 30-40 km of ground zero, almost all trees were uprooted, burnt, or blown flat.
- The destruction formed a radial pattern away from the blast site
What Caused the Tunguska Explosion?
The explosion was caused by the breakup of a large meteorite (~50 meters in diameter) at about 6 km in the atmosphere.
Energy released was equivalent to 1,000 Hiroshima bombs.
Analysis of tree resin particles showed a composition similar to a stony meteorite, rich in iridium.
No crater formed, as the object exploded in the atmosphere.
What real comet impact inspired Deep Impact?
- Comet Shoemaker-Levy 9
- First observed real-time collision of a large object with a planet
- Impacted Jupiter in July 1994
What happened to Comet Shoemaker-Levy 9 before it hit Jupiter?
- Discovered in 1993
- Broke apart due to tidal stresses from Jupiter’s gravity
- Split into over 20 fragments
How powerful was the impact of Shoemaker-Levy 9?
- Fragments were kilometre-scale
- Hit Jupiter at speeds of 60 km/s
- Caused massive atmospheric explosions and scars on the planet
How did the impact of Shoemaker-Levy 9 on Jupiter look?
The pieces of comet
were like flies on a
planetary windshield.
What were the effects of Shoemaker-Levy 9’s impact on Jupiter?
- Left huge impact scars in Jupiter’s upper atmosphere
- Scars were Earth-sized
- Took months to fade
Could a Shoemaker-Levy 9–type impact affect Earth?
Yes, if a similar-sized object hit Earth, the damage would be catastrophic
How often do large impacts happen compared to small ones?
- Frequency and size are inversely proportional
- Large impacts = rare
- Small impacts = more common
(Thankfully, big ones are not frequent)
What was NASA’s “Deep Impact” mission?
- Spacecraft launched by NASA on Jan 12, 2005
- Target: Comet Tempel 1 (orbit between Mars & Jupiter)
- Mission goal: study the interior of a comet
What did the Deep Impact mission do to the comet?
- Impacted the comet with a 370 kg copper mass
- Purpose: to observe ejecta and composition from the impact
What did scientists learn from the Deep Impact mission?
Observed:
- Impact crater
- Ejecta composition
-Comet behavior
- Ejecta had more rock dust and less water than expected
