Doomsday Asteroid Video

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This 1997 video from NOVA (transcript available) presents evidence that dangerous meteorites continue to strike our planet. The video also describes what we would have to do to detect these meteorites before they hit us, and some possible ways for us to defend ourselves.

Part 1.
1. What happened in 1908 in Siberia?

2. Describe what the scientist found when he investigated the Tunguska     disaster.
  

3. When did the meteorites hit Wethersfield CT?

4. What are comets and asteroids?

5. Where are most asteroids? Comets?

6. How are asteroids and comets different?

7. What happened 3 billion years ago?

8. Define a meteorite:

9. What happens to meteorites as they go through the atmosphere?

10. How fast do meteorites enter the atmosphere?

11. Hundreds of thousands of tons of rock fall to Earth each year as:

12. What evidence is there about a meteorite that hit Australia 5,000      years ago?
   

13. What did the ancient Incas in S. america witness? What modern      evidence is there of this?

14. What evidence is there for meteorites before the age of science?

15. Why was catastrophism relegated to science fiction?

16. What brought "fireballs" back into mainstream science?

17. Describe the shape of an impact depression:

18. Why does the Moon provide a record of the rate of meteorite      impacts?

19. Why doesn't the Earth look like the Moon?

20. How many impact craters have been identified around the world?

21. How do scientists look for Earth-orbit crossing asteroids?

22. Why do asteroids in the asteroid belt leave that area?

23. Where do comets come from? Why?

24. Describe the first evidence that it was an asteroid that killed      the dinosaurs.

25. Why were dinosaur scientists skeptical of the meteorite impact      theory of dinosaur extinction?

26. How much energy would be released by a 10 km meteorite? How many      times the worlds entire nuclear arsenal is this?

27. How was the dinosaur killing crater found? Where is it?

28. Describe some of the possible effects of the dinosaur killing      impact.

29. How much of the life on Earth was destroyed?

end part 1

   
                     ENVIRONMENTAL EARTH SCIENCE
                       DOOMSDAY ASTEROID VIDEO

Part 2

1. How often can large meteorites be expected?

2. How often can smaller, but still destructive meteorites hit?

3. What percent of the possible Earth-crossing meteorites have been     identified?

4. How long will it take us to find all the asteroids that cross     Earth's orbit?  Why?

5. How many rocks are probably out there?

6. Why is it difficult for astronomers to spot asteroids?

7. How is the military involved in the search for impact evidence?

8. What does the old Strategic Defense Initiative (SDI) have to do     with meteorites?

9. How could we use nuclear weapons to nudge an asteroid so it misses     the Earth?  How much warning would we need?

10. What questions need to be answered before we can use missiles to      defend Earth?

11. What problems and risks are there to building an asteroid defense      system?

12. What do we need to find out in order to design an asteroid defense      system?

13. Describe what we know about the near-Earth asteroid Toutaitis:

14. Describe the satellite mission to Eros (the very successful mission of the spacecraft NEAR Shoemaker ended when it landed on Eros Feb. 12, 2001):

15. Why did we need to send a satellite to an asteroid?

16. Why was the discovery of the comet heading for Jupiter so      significant to the growth of scientific knowledge?

17. Compare the explosion at Tunguska with the explosion of the      largest comet fragment.

18. How big were the black spots caused by the explosion of the comet      fragments?

19. Why have people been treating the risk from impact as silly?

20. The risk from a meteorite impact is similar to the risk from:

21. How much would you be willing to spend each year to expand our      knowledge of meteorites and comets, and to plan our planet's      defense in case we discover one heading for Earth?

22. Explain why you would spend that much and not more or less.

22. If everyone in the United States was willing to spend this much,      how much would that be each year?
   

    
23. Write a letter below to try to convince a Senator of your opinion      on the amount of money we should spend on meteorite defense.   Use     evidence (facts) from the video to make your point.

   
Part 1.
1. What happened in 1907 in siberia?
   a large meteorite blew up in the atmosphere
   

   
2. Describe what the scientist found when he investigated the Tunguska     disaster.
  

3. When did the meteorites hit Wethersfield CT?
    1982, 1972

4. What are comets and asteroids?
   small bodies are remnants of early solar system, leftover icy or rocky materials

5. Where are most asteroids? Comets?
    asteroids in belt in inner, comets in outer

6. How are asteroids and comets different?
    asteroids rocky, comets icy

7. What happened 3 billion years ago?
   the main bombardment ended, allowing life to evlove
                                                                        8. Define a meteorite:
an object from space that falls to the planets surface.

9. What happens to meteorites as they go through the atmosphere?

outside melts, forming fusion crust

10. How fast do meteorites enter the atmosphere?
    40 * speed of sound, 11,000 km/sec

11. Hundreds of thousands of tons of rock fall to Earth each year as:
    dust

12. What evidence is there about a meteorite that hit Australia 5,000      years ago?
    aborigine legends, names for 13 craters
   

13. What did the ancient Incas in S. america witness? What modern      evidence is there of this?
200m rock,  wall of flame rollled for miles, burned everyhing.  teardrop scars in Pampas

14. What evidence is there for meteorites before the age of science?
early writtten records - chinese records, blame fireballs on angry gods, hurling of gods thunderbolts, heavens seen as source of potential disaster.

15. Why was catastrophism relegated to science fiction?
age of enlightenment, Newton's laws of gravity, uniformitarianism, presented image of the universe as operating like a clock, Huxley's debate with Bishop Wilberforce that Huxley won, since then, catas. discredited,

16. What brought "fireballs" back into mainstream science?
1950's - crater in Arizona proved to be meteorite by relating structure to nuclear crater by Shumaker

17. Describe the shape of an impact depression:
rocks pushed out, peeled up and overturned, rocks collapse downward, raised center, ring depression,

18. Why does the Moon provide a record of the rate of meteorite      impacts?
no weather, no erosion,

19. Why doesn't the Earth look like the Moon?
weathering wears them down, filled in,

20. How many impact craters have been identified around the world?
almost 200

21. How do scientists look for Earth-orbit crossing asteroids?
telescopes scan large part of the sky, look for streaks on photos against starry background,

22. Why do asteroids in the asteroid belt leave that area?
    orbits get disturbed by Jupiter

23. Where do comets come from? Why?
    Oort cloud distrupted by passing star, Kuiper belt also.

24. Describe the first evidence that it was an asteroid that killed      the dinosaurs.
    iridium was found in the layer that separates the layers of dino fossils from those later.

25. Why were dinosaur scientists skeptical of the meteorite impact      theory of dinosaur extinction?
    no clear proof, no crater, preffered gradual change explanations, paleontologists not familiar with more recent info on meteorite

26. How much energy would be released by a 10 km meteorite? How many      times the worlds entire nuclear arsenal is this?
all nukes in the world going off at once - 1 billion megatons of energy

27. How was the dinosaur killing crater found? Where is it?
Yucatan penisula - they were looking for oil by measuring faint varaitions in mag field - found a ring 1 mile below surface dated to 65 mya with uplift in center -
                              

28. Describe some of the possible effects of the dinosaur killing      impact.
    enviro shock - debris affecting all hemis - could have tons of sulfur rock, ignited skies, fire throughout planet lava flows, darkness, lighting, high temps, millenia of destruction

29. How much of the life on Earth was destroyed?
90 % bioamass burned, 2/3 species extinct,

end part 1                
                     ENVIRONMENTAL EARTH SCIENCE
                       DOOMSDAY ASTEROID VIDEO

Part 2

1. How often can large meteorites be expected?

2. How often can smaller, but still destructive meteorites hit?

3. What percent of the possible Earth-crossing meteorites have been     identified?
  

4. How long will it take us to find all the asteroids that cross Earth's orbit?   Why?

5. How many rocks are probably out there?

6. Why is it difficult for astronomers to spot asteroids?

7. How is the military involved in the search for impact evidence?

8. What does the old Strategic Defense Initiative (SDI) have to do     with meteorites?

9. How could we use nuclear weapons to nudge an asteroid so it misses     the Earth?  How much warning would we need?

10. What questions need to be answered before we can use missiles to      defend Earth?

11. What problems and risks are there to building an asteroid defense      system?

12. What do we need to find out in order to design an asteroid defense      system?

13. Describe what we know about the near-Earth asteroid Toutaitis:

14. Describe the proposed satellite mission to Eros:

15. Why do we need to send a satellite to an asteroid?

16. Why was the discovery of the comet heading for Jupiter so      significant to the growth of scientific knowledge?

17. Compare the explosion at Tunguska with the explosion of the      largest comet fragment.

18. How big were the black spots caused by the explosion of the comet      fragments?

19. Why have people been treating the risk from impact as silly?

20. The risk from a meteorite impact is similar to the risk from:

21. How much would you be willing to spend each year to expand our      knowledge of meteorites and comets, and to plan our planet's      defense in case we discover one heading for Earth?

22. Explain why you would spend that much and not more or less.

22. If everyone in the United States was willing to spend this much,      how much would that be each year?
   

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