Dan_Harris Posted December 12, 2003 Share Posted December 12, 2003 Story about Earth's magnetic field What is going to happen to those of us that do not use GPS and rely on the old fasioned method of map and compass? Provided it happens and I'm still around. Quote Link to comment Share on other sites More sharing options...
Lambone Posted December 12, 2003 Share Posted December 12, 2003 post this kind of stuff in Spray por vavor Quote Link to comment Share on other sites More sharing options...
Alpinfox Posted December 12, 2003 Share Posted December 12, 2003 Dan_Harris said: [What is going to happen to those of us that do not use GPS and rely on the old fasioned method of map and compass? Â OH SHIT! IT'S THE APOCALYPSE!!! WE'RE ALL DOOMED! SOCIETY WILL BREAK DOWN! CARROTS WILL GROW IN TO THE EARTH! PIGEONS WILL GET LOST!!! DOGS AND CATS, LIVING TOGETHER! EEEKEKEKKE!!!! Â oh wait... what's this bezel thing... oh, I can just turn it 180 degreees!?!?! problem solved! Â Quote Link to comment Share on other sites More sharing options...
cj001f Posted December 12, 2003 Share Posted December 12, 2003 Alpinfox said:oh wait... what's this bezel thing... oh, I can just turn it 180 degreees!?!?! problem solved! No! You have to buy the special Southern Hemisphere compass! Quote Link to comment Share on other sites More sharing options...
Alpinfox Posted December 12, 2003 Share Posted December 12, 2003 Â Well, ain't you a smarty pants! Â Â "An interesting detail is that there are northern- and southern-hemisphere compasses. This has to do with the fact that the magnetic field lines, to which a compass needle aligns, point into the earth at the north and south magnetic poles. In the northern hemisphere the north end of the needle is pulled downwards, and the south end is counterweighted to balance the needle. When you use a northern hemisphere compass in, say, Australia, the south end of the magnet is pulled downwards by the magnetic field, and is also heavier than the north end - resulting in a needle that catches and drags on the bottom of the compass housing when the compass is held horizontal. " Â Source: some website. Quote Link to comment Share on other sites More sharing options...
Dan_Harris Posted December 12, 2003 Author Share Posted December 12, 2003 Lambone, I posted it here since many people use compass and map. Tambien, cuando hablando en espanol, la palabra es por favor. Â Alpinfox, so that is what the little spinny ring on my compass is for! Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted December 12, 2003 Share Posted December 12, 2003 NOVA had a really interesting program on the subject. There is a guy who has been doing computer simulation of the earth's core which show that as the magnetic field is getting ready to reverse polarity it gets weaker, as it is doing now and it also becomes chaotic with as many as four "poles" forming that move rapidly about almost any part of the earth's surface. Â They visited this place in Oregon called Steen's Mountain where they took a bunch of cores from rocks which had been molten during one of these transistions. They found differences in rocks which had solidified only hours apart. If one had been there at the time with a compass, you could watch the needle rotate at up to 6 degrees per hour. Quote Link to comment Share on other sites More sharing options...
Dru Posted December 12, 2003 Share Posted December 12, 2003 see what the geeks have to say about pole reversal! Quote Link to comment Share on other sites More sharing options...
Dan_Harris Posted December 12, 2003 Author Share Posted December 12, 2003 CBS, cool. Is there any local magnetic problems at Steens Mtn.? Dru, what is the site you linked to. My work denies me access. Quote Link to comment Share on other sites More sharing options...
cluck Posted December 12, 2003 Share Posted December 12, 2003 Excellent.... my SUV is causing the Greenhouse Affect and destroying the magnetic field! Finally, my diabolical scheme has come to fruition!! Quote Link to comment Share on other sites More sharing options...
chelle Posted December 12, 2003 Share Posted December 12, 2003 Pretty interesting Dan. Thanks. Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted December 13, 2003 Share Posted December 13, 2003 I forgot to mention what I thought was the most interesting theory from the NOVA show. Mars has only 1/100 of the atmosphere of earth and its magnetic field has ceased to exist. Recent measurements by spacecraft orbiting Mars have detected islands of residual magnetism in rocks on the surface that are thought to reflect the former magnetic field of the planet. The theory goes that because Mars is smaller than Earth, its core cooled off faster and the iron core solidified and stopped flowing. This extinguished the magnetic field. Without the magnetic field to direct charged particles towards the poles and away from the atmosphere, the air was eroded and carried away into space bit by bit, resulting in a dead planet. Â When earth's magnetic field undergoes reversal, the same thing happens to its atmosphere. However the total amount of time over which this state exists is relatively short on a geological scale. Not enough atmosphere is lost in those brief periods to be significant. However if you happened to be around during those periods you would be treated to fantastic aurora displays anywhere on the planet at any season. Quote Link to comment Share on other sites More sharing options...
klenke Posted December 13, 2003 Share Posted December 13, 2003 I've often conjectured that the extinction of the dinosaurs might have been due to an abnormally prolonged duration in one of these non-field states. Or maybe I just thought it made for a good story. Nonetheless I remember learning about the Earth's pole reversals as a kid and thinking it was one of the coolest things I ever came to know. It still is that way, more or less. Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted December 13, 2003 Share Posted December 13, 2003 The extinction of the dinosaurs 65 Million years ago was the first mass dying that was attributed to an asteroid impact. In this case, the impact was thought to have occurred in Honduras and the theory is supported by the discovery of a layer of the rare precious metal, iridium at the so-called K-T boundary. Â The much earlier Permian extinction, in which 90% of species were wiped out, is also thought to have been the result of an asteriod impact. For some reason there is no iridium layer at the Permian-Triassic boundary, as one would expect. New evidence in the form of "shocked quartz" lends support to the theory. My guess was that the Cretaceous extinction was caused by an iron metorite, whereas the Permian was caused by a comet impact or less likely a stony metorite, if such a thing exists of sufficient size. Quote Link to comment Share on other sites More sharing options...
klenke Posted December 13, 2003 Share Posted December 13, 2003 The asteroid/comet cause for the extinction is still a theory. Your first sentence intimates to the contrary. I will agree with you that the asteroid/comet theory holds the most water (at least in our current understanding). Â It's like global warming: that the causes are anthropomorphic is stil just a theory, despite what the media (and non-scientists on this site who learn only through what they hear in the media) want you to believe. "It's real it's real it's real!" they blast. It's possible, maybe even probable, but definitely not certain. Quote Link to comment Share on other sites More sharing options...
scrambler Posted December 13, 2003 Share Posted December 13, 2003 catbirdseat said: The extinction of the dinosaurs 65 Million years ago was the first mass dying that was attributed to an asteroid impact. In this case, the impact was thought to have occurred in Honduras and the theory is supported by the discovery of a layer of the rare precious metal, iridium at the so-called K-T boundary. Â The much earlier Permian extinction, in which 90% of species were wiped out, is also thought to have been the result of an asteriod impact. For some reason there is no iridium layer at the Permian-Triassic boundary, as one would expect. New evidence in the form of "shocked quartz" lends support to the theory. My guess was that the Cretaceous extinction was caused by an iron metorite, whereas the Permian was caused by a comet impact or less likely a stony metorite, if such a thing exists of sufficient size. Â Â It's more correct to say that the bolide impact was the final nail in the coffin. The 'dinosaurs' were already in decline before the K-T event and for a variety of factors including the rise of angiosperms, changes in continental configuration, etc. Â Same with the Permo-Triassic mass extinction. A host of changes were occurring over time. The aggregation of the continental landmasses to form the supercontinent, Pangea, effectively reduced the area of continental epeiric seas thus eliminating many shallow water fauna. Other associated changes occurred such as changes in upwelling. The fossil record is biased towards shallow water marine invertebrates with regard to preservation, thus the percentage of species extinction is set at 96%. Â You're not looking at single causes but instead a dynamic earth with secular and cyclical changes within its coupled earth systems. Â Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted December 13, 2003 Share Posted December 13, 2003 Scrambler, your knowledge of the subject vastly exceeds my own. Quote Link to comment Share on other sites More sharing options...
Harry_Pi Posted December 13, 2003 Share Posted December 13, 2003 Hello capitalist! The earth is also flat. You people sound just like my brother, a total geek Post Hole Digger. Thank you for allow asian to post. Quote Link to comment Share on other sites More sharing options...
Fairweather Posted December 13, 2003 Share Posted December 13, 2003 catbirdseat said: NOVA had a really interesting program on the subject. There is a guy who has been doing computer simulation of the earth's core which show that as the magnetic field is getting ready to reverse polarity it gets weaker, as it is doing now and it also becomes chaotic with as many as four "poles" forming that move rapidly about almost any part of the earth's surface. Â They visited this place in Oregon called Steen's Mountain where they took a bunch of cores from rocks which had been molten during one of these transistions. They found differences in rocks which had solidified only hours apart. If one had been there at the time with a compass, you could watch the needle rotate at up to 6 degrees per hour. Â I watched that show last week. Amazing. I believe that they came to the conclusion that even if we are in the early stages of a flip, the consequences are not all dire for humanity. A higher cancer occurance rate for sure, but not mass death and starvation. (The show did not address the consequences of an unusually large solar eruption during the 'down' period though.) Â That computer simulation was run inputing 'all known data', but the show was light on specifics re that data. I've always been curious about the role that our unusually large moon and it's gravity plays in the formation of our planet's strong magnetic field. Catbird? Quote Link to comment Share on other sites More sharing options...
JoshK Posted December 13, 2003 Share Posted December 13, 2003 klenke said: It's like global warming: that the causes are anthropomorphic is stil just a theory, despite what the media (and non-scientists on this site who learn only through what they hear in the media) want you to believe. "It's real it's real it's real!" they blast. It's possible, maybe even probable, but definitely not certain. Â I'm not saying you are arguing otherwise but the vast majority of the scientific community believes an overwhelming amount of evidence points to humanity having a good part to do with global warming in the past 100 years. I'm not sure how or if we'll ever have the data to model what the environment would be like without or presence, but the fact remains that nearly every expert in the field will tell you that the evidence is good enough to support doing something about it, and doing it now. Â Despite this, president bush and his pathetic cabinent collect enough quotes and support from the naysayers to claim legitimate reason for abandoning global economic treaties, opposing higher fuel standards, and giving patheticly half hearted support to alternative energy sources and plans to wean us off the tit of fossil fuels. Â But why would we care about that? After all, he is making the world a better and safer place for us! Oh...wait... Quote Link to comment Share on other sites More sharing options...
JoshK Posted December 13, 2003 Share Posted December 13, 2003 Speaking of the moon, does anybody have any good links to info on the tidal water energy production technology? I saw a brief blurb on it and it looked interesting... Quote Link to comment Share on other sites More sharing options...
EWolfe Posted December 13, 2003 Share Posted December 13, 2003 JoshK said: Speaking of the moon, does anybody have any good links to info on the tidal water energy production technology? I saw a brief blurb on it and it looked interesting... Â Here's a good one. Quote Link to comment Share on other sites More sharing options...
Dan_Harris Posted December 13, 2003 Author Share Posted December 13, 2003 (edited) I have a friend who worked on a research ship doing Ocean Thermal Energy Conversion studies. Seems to me to be a good source of electrical energy. Edited December 13, 2003 by Dan_Harris Quote Link to comment Share on other sites More sharing options...
klenke Posted December 13, 2003 Share Posted December 13, 2003 JoshK said:I'm not saying you are arguing otherwise but .... safer place for us! Oh...wait... Case in point. Quote Link to comment Share on other sites More sharing options...
JoshK Posted December 14, 2003 Share Posted December 14, 2003 klenke said: JoshK said:I'm not saying you are arguing otherwise but .... safer place for us! Oh...wait... Case in point. Â Ya lost me there... The brain is working on 3 cylinders today, help me out. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.