from: WGBH Boston
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Audience Rating: NR (Not Rated)
Binding: DVD
Brand: Nova
EAN: 9781593751074
Format: Closed-captioned, Color, DVD, Letterboxed, NTSC
ISBN: 1593751079
Label: WGBH Boston
Languages: EnglishOriginal Language
Manufacturer: WGBH Boston
MPN: WGBD37009D
Number Of Items: 1
Publisher: WGBH Boston
Region Code: 1
Release Date: February 17, 2004
Running Time: 60 minutes
Studio: WGBH Boston
Theatrical Release Date: 2003
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Editorial Review:
Product Description:
Studio: Wgbh Wholesale Release Date: 02/17/2004 Run time: 60 minutes
Average Rating: 
Rating:  -
NOVA - Magnetic Storm (2003) was another good science special on the Earth's magnetic field which has been determined to be rapidly weakening based on it's current rate of change. The field may weaken to very low levels in the 21st century and then actually reverse resulting in a change in direction indicated on a compus. Also, during the very weak phase just prior to reversal, a significantly increased incidence of cancers may result in our children's lifetime which will be a problem. This is a much less serious scenario than the fictional story discussed in the sci-fi film "The Core", but still serious enough to warrant our attention.
The special discussed in some detail the ongoing transient in the Earth's liquid iron core which has been modeled by numerical integration (via time history analysis) on the super computer to weaken and reverse with time. The period appears to average out at about 200,000 years with a low of less than 100,000 years to a maximum of perhaps 1,000,000 years. Since 700,000 years have passed since the last one we are probably past due.
The reasons given for field reversals appear to have something to do with changes in liquid flow in the iron core due to convection coupled with other perhaps electrodynamic effects within the core. Some great computer graphics were exhibited demonstrating how the magnetic field is predicted to change which I wish more information had been provided on. I have done some numerical integration on the digital computer in thermal work and orbital mechanics and feel that greater detail could have been provided (on at least an intuitive level) on what is happening in the liquid core of the Earth. The film definitely deserves four stars but felt it required far more detail on exactly what is causing the periodic time history in the direction of the magnetic field of the Earth indicated by the geologic record.
Rating:  -
I enjoyed watching this DVD and learn a lot from it.
Thanks to NOVA. A great contribution to the public and people who are curious about the science.
Rating: -
The electromagnetic field of earth explains why earth's atmosphere has remained stable while Mars has lost most of it's atmosphere. It also surprises in that our North and South Poles switch places over a relatively short cosmic period of time - 200,000 years, and that we are now experiencing a rapid change with the predicted reversal in 300 years. This is a fascinating detective story that started with data from Mars showing that it had an atmosphere and water at one time, but why did it disappear? Rocks on mars showed it had a magnetic core about 4 billion years ago, but that it solidified and Mars electromagnetic field disappeared with the water and atmosphere.
From this the mystery of whether Earth will lose its field or not is solved using surprising sources. Clues from ancient clay-fired pottery, volcanic rocks, 300 year old ship logs, and many other pieces of data are put into NASA and Government computers for 6 months of processing to find that we will not lose our life-saving shield for hundreds and thousands of years, but it will continue to shift. Why it shifts is not answered, nor what happens with weather, global warming. They think there will be more "Northern" lights displays all over the world and a slightly higher incidence of cancers during the shift.
Rating: -
A marvelous collection of current research on the Earth's magnetic field. The only video I have that other science teachers keep borrowing and borrowing. It starts with reasonable questions about the possible disappearance or change of our magnetic field and clearly and logically follows the chain of research up to what we know in the current day. The use of ancient pottery, Hawaiian lava, the Royal Navy, and other compelling evidence ends with a clear and understandable picture of our current understanding. The final questions and possible futures it ends with have been starting points for some great discussions. In a decade or two research might make this show outdated, but it is currently wonderful.
Rating: -
I had seen part of the Magenetic Storm months ago on KQED. It is an amazing story about magnetic polarity of the earths core. It also gives you an better uderstanding of global warming, in directly. Very educational!
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