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NOVA Magnetic Storm
1. Why are scientists concerned about the present situation of the Earth’s magnetic field?
The strength of the Earth’s magnetic field is rapidly decreasing
2. Was Mars always a sterile planet?
No, there is evidence that there was water, volcanoes, and a magnetic field
3. What happened to Mars’s atmosphere and oceans?
The atmosphere and oceans disappeared. This may have been caused by impacts from meteorites or solar
winds
4. What evidence told Mario Acuna that the Martian magnetic field ceased to exist about 4 billion years ago?
There is evidence in the crust to show us the changes in Mar’s (now nonexistent) magnetic field
5. Why are ancient pots called magnetic time capsules?
The rocks line up according to the magnetic poles. When the poles switch, so does the arrangement.
6. What did the ancient pots tell us?
The ancient pots tell us that the magnetic field is weakening.
7. Prof Dan Latham modeled the Earth’s magnetic core using molten spinning sodium to create a self-sustaining
dynamo. What material in the Earth has to stay in constant motion in order to sustain the dynamo effect?
The liquid metal in the core needs to stay in constant motion in order to sustain the dynamo effect.
8. What is Dan’s hypothesis as to why Mars’s magnetic field died?
Solar winds, impacts from meteorites, and the cooling core may have caused the magnetic field to die.
9. How long will it take for the Earth’s core to cool?
It is estimated to take 4 billion years for the Earth’s core to cool.
10. If the strength of the Earth’s B field is being lost quickly yet it is not due to the cooling of the core then what
is causing the rapid decrease of the B field?
Solar flares may be causing the Earth’s magnetic field to decrease. Also, it might be due to the length of time
since the magnetic poles last switched places (780,000 years).
11. Mike Fuller studied lava flow at the sea coast of the big island of Hawaii. The millions of years of lava flow is a
hidden chronicle of the earth’s magnetic field. It told us that 780,000 years ago, the field was _opposite_. Older
and older lava told us something else. It showed a reversal occurs on average once every _200,000 years__.
12. Gary Glatsmire’s computer model had spontaneous reversals happen every 100,000 years or so of simulated
time. What happened to the field strength of Gary’s model just before the field reversal?
The process began the same way every time the poles reversed. The magnetic field was at its weakest.