Radion

Stop-and-go plate tectonics Ancient crustal plates may have dived deep, time and again By Alexandra Witze Web edition : Monday, April 9th, 2012 Text Size ENLARGE HOT EARLY MANTLEA simulation of plate tectonics today (left) shows a crustal slab (green) plunging more than 400 kilometers into Earth\'s mantle. Billions of years ago (right), when the mantle was 200 degrees Celsius hotter, the slab would have barely penetrated the depths before breaking off and foundering. Geologists propose this difference led to intermittent plate tectonic activity early in Earth\'s history.J.F. Moyen et al/Geology 2012 Plate tectonics might have gotten a fitful start on the early Earth. Today, the process of Earth’s crustal movement called plate tectonics dictates nearly everything about the planet’s appearance, from the sites and heights of the mightiest mountain ranges to the depths of the oceans’ trenches. But geologists have long argued about when thin, rigid crustal plates first formed on the young planet and began jostling against one another. Now, two researchers propose that plate tectonics started and stopped over and over, billions of years ago, before running continuously. The work, published online March 26 in Geology, could explain how a sort of proto-plate tectonics on the hot early Earth evolved into the style geologists see today. “As far as I’m aware we are some of the first people to come up with this scenario to explain how plate tectonics started,†says Jeroen van Hunen, a geophysicist at Durham University in England who did the work with Jean-François Moyen, of Jean Monnet University in Saint-Etienne, France. A defining feature of plate tectonics is how one crustal plate sometimes dives beneath another, a process known as subduction. When that diving plate gets deep enough, the high pressures and temperatures inside Earth chemically change its rocks. If those rocks are later uplifted to the surface, geologists can recognize the chemical alteration and show that plate tectonics has occurred. Many scientists have spotted this signature in rocks from the Archean eon, which stretched from about 3.8 billion to 2.5 billion years ago, and so have argued that plate tectonics must have happened then. But the Earth’s mantle, or layer beneath the crust, was also several hundred degrees Celsius hotter thanks to residual heat from the planet’s birth. A hotter mantle makes subduction tough, because the diving edge of the crustal plate weakens and breaks off before the plate can get too deep. So Moyen and van Hunen decided to look for evidence of short-term plate tectonics. Some ancient outcrops, as in western Australia and in Zimbabwe, show altered rocks interleaved with more pristine rocks in layers formed every couple of million years. These repetitions may represent subduction turning on and off and on again over time, the scientists say. Next they simulated how plates might subduct under various mantle temperatures. At temperatures 200 degrees hotter than today, the calculations showed how crustal plates would make it only partway down before breaking off and foundering. “Each time a slab breaks off, you temporarily stop the whole process,†says van Hunen. “It’s not so easy to get a subduction system going. You get a kind of start-and-stop scenario.†Plates would then have to cool at the surface and become dense enough to again start sinking into the mantle, starting the process over. Only when the mantle cooled sufficiently — perhaps by around 2.7 billion years ago — could permanent, modern-style subduction take hold. Of course, “a sporadic record of subduction is not the same as sporadic subduction,†says Hugh Rollinson, a geologist at the University of Derby in England who has studied Zimbabwe’s Archean rocks. But he says the basic concept, that plate tectonics emerged intermittently, is “a good idea, and one to test.†I was doing a science report, and we have to provide our source material. The spoiler wasn\'t copied, its courtesy.

Teaching by talking non-stop is perhaps the worst method of doing so. Now, I\'m only 13, but I find I learn more from teachers who talk less, and actually interact with us during the lesson, instead of blaring on like some other teachers.

Sorry, didn\'t see that Albania has already been mentioned. I have edited the original.

Albania Antigua & Barbuda

I think I could call 15 coal power plants per week, relaxed environmental regulations, horrid pollution, crumbling industry in Manchuria, and depending on the US buying their products to survive dangerous practices.

I guess 'self-destructive' wasn\'t the best term, but actively pursuing more nuclear technology, building tunnels for your ICBM\'s, increasing your military spending while your economy grows, growing your economy on dangerous practices, both environmentally and economically, basing your entire system on finite supplies and demand, and overall repression is generally referred to as self-destructive. Besides, its not going to be a superpower anytime soon, as expressed here: http://articles.businessinsider.com/2010-05-05/markets/29990937_1_china-chinese-gdp-jiang-zemin

I am reposting it from the 'rant' thread, as I feel it is important for this to be heard. Do with it what you will, and please note that it is not 'all-inclusive,' there are many other arguments that can be made for either party. First and foremost, the United States of America is theorized to have won the War of American Independence (I\'ll be calling it that for the duration of this publication, out of respect to other wars of independence) because of several reasons. One of which, is the difficulty the British army faced in transporting their troops across the Atlantic Ocean to the closed American ports. The second reason can be attributed to terrain and tactics. The British occupying army based mostly in Boston and New York, had little in the way of experience with the terrain beyond the major cities. The British Army also used standard European tactics that were simply ill-suited to the terrain of the East Coast. The US Army used European tactics sparingly, resorting to gradual degradation of the enemy army for long periods of time, then a large attack to bring it down. Both armies made major headway, but ultimately it was a combination of degrading British morale and the entrance of the French and Spanish into the war that finally drew it to a close in 1781. Now, the War of 1812 is as much a controversial point as any other. Many Americans say the US won (despite it being more of a draw), and some (if not many, I can\'t confirm this part) British support their winning the war. The truth of the matter is that it is mostly a draw, coming to a close for again, costs, tactics, and more important matters. Major headway was again gained by both sides, including the Americans burning Toronto, and the British burning of Washington. The Battle of Fort McHenry (The inspiration of the song, The Star Spangled Banner) was a major victory and rallying point on the American side, and most British people rally towards the Washington Fiasco in regards to this war. Things can best be reviewed here as a draw, to put it concisely. Through out the rest of the 19th Century, British innovation largely outpaced that of America, until after the American Civil War, that is. After the war, various American inventions were patented (between 1865 and 1882: 2, 519, 557. The numbers grew too long to do efficiently up to 1900). However, the UK was the major superpower of the 19th Century, and it is in part that the UK did not enter the American Civil War that the Union managed to bring down the Confederacy. Now, the 20th Century can best be seen as a combination of both American and British innovation, with American innovations being more prevalent and reported over. In the early 20th Century, Americans invented the first 'flying machine,' so to speak, thus bringing in the era of the airplane. Major American innovations of the period are quite easy to find. Now, the British had their day during WWII, successfully defending themselves against the German armies. The 20th Century really exemplifies cooperation between the two nations. During WWII bombing raids, the US bomber planes went by day, and the British by night, using both of the nations\' abilities to accomplish a common goal. The US went to the Moon, and created several new space technologies that brought new inventions to the scene. The British also had their share of accomplishments. The creation of a VTOL plane, defending themselves during the 'Battle of Britain,' taking the fight to them, fighting along side US forces all over the globe, and many others. However, neither side was perfect. The United States had a little fiasco called, 'the Vietnam War,' in which it basically repeated every mistake the UK made during the War for American Independence. There\'s also the matter of the nuclear bombs of Hiroshima and Nagasaki, killing millions over the next few decades. The CIA (US Intelligence Agency (no pun intended)) armed Afghan rebels (the precursor to the Taliban) against the Soviet Union, only to later have the nation turn against it. The British were not without fault either. The Irish rebellion is a gruesome reminder of the possibility of brutality by British forces. Then, there\'s the Bengal famine of 1943 (which England has yet to recognize), during which Winston Churchill ordered mass stockpiles of food and grain to be removed from the area in case of Japanese attack, killing between 3 and 9 million Bengali (estimates vary). As for language, both versions are correct. English is the main (or group) language, much as English is part of the larger Germanic (and Indo-European) language group. Beneath 'English' are various dialects that are all correct and should not be discriminated against. American English and British English (not 'true' English, as many tout) are both correct in their respective areas. Whatever words that are spelled differently are simply a matter of custom. Yes, many words were spelled 'incorrectly' in the first version of Webster\'s Dictionary, but Webster\'s personal accounts point to him wanting to create a national linguistic identity for the fledgling seaboard republic, and to help unify it, and separate it from England (contempt for England was pretty high in the early 1800\'s). However, soon enough these misspellings became common enough that when the accents changed, and various parts of syntax and grammar as well, American English became its own dialect. In essence, one cannot claim the superiority of one nation without having to look at that nation\'s faults. Both the United States and the United Kingdom have their virtues and vices, and both have their own manner of doing things. Whenever one does something, another does something else that helps to balance things out. American innovation is not playing catch-up to that of Britain, as many would claim. The US is the world\'s only superpower (China is not a superpower, get over it. Its far too self-destructive and unmanageable), and leads the world on many issues, to the disdain of those who don\'t. Yet Britain is also important. It has a massive history spanning millenia, and has had its own centuries to lead the world. Neither has been, is, or ever shall be perfect. The important thing, is that they are both together as brethren, and the citizens should be as well. Whenever a British person yells on the internet at an American, calling them 'fat; idiot american; etc.,' I am appalled, but I am just as equally appalled at Americans yelling British stereotypes. Hopefully, this makes it clear that neither nation is superior historically, and factually neither stereotype has any true ground (besides the obesity, buts a global epidemic. Although I will admit, McDonalds is the only thing you can forget to get on the exit for and say, 'Oh well, I\'ll get the next one. Its only a few yards away.'). Thank you, and have a nice day. - Your average American.

If that\'s in response to me, I am not making that point. Of course, you are correct.

I am going to die. As an American, I am appalled at the this discourse, and will do my best to be as concise as I can without feeling I said too little. Now, if you excuse me, I\'ll be reserving this post for me soon-to-be long post. First and foremost, the United States of America is theorized to have won the War of American Independence (I\'ll be calling it that for the duration of this publication, out of respect to other wars of independence) because of several reasons. One of which, is the difficulty the British army faced in transporting their troops across the Atlantic Ocean to the closed American ports. The second reason can be attributed to terrain and tactics. The British occupying army based mostly in Boston and New York, had little in the way of experience with the terrain beyond the major cities. The British Army also used standard European tactics that were simply ill-suited to the terrain of the East Coast. The US Army used European tactics sparingly, resorting to gradual degradation of the enemy army for long periods of time, then a large attack to bring it down. Both armies made major headway, but ultimately it was a combination of degrading British morale and the entrance of the French and Spanish into the war that finally drew it to a close in 1781. Now, the War of 1812 is as much a controversial point as any other. Many Americans say the US won (despite it being more of a draw), and some (if not many, I can\'t confirm this part) British support their winning the war. The truth of the matter is that it is mostly a draw, coming to a close for again, costs, tactics, and more important matters. Major headway was again gained by both sides, including the Americans burning Toronto, and the British burning of Washington. The Battle of Fort McHenry (The inspiration of the song, The Star Spangled Banner) was a major victory and rallying point on the American side, and most British people rally towards the Washington Fiasco in regards to this war. Things can best be reviewed here as a draw, to put it concisely. Through out the rest of the 19th Century, British innovation largely outpaced that of America, until after the American Civil War, that is. After the war, various American inventions were patented (between 1865 and 1882: 2, 519, 557. The numbers grew to long to do efficiently up to 1900). However, the UK was the major superpower of the 19th Century, and it is in part that the UK did not enter the American Civil War that the Union managed to bring down the Confederacy. Now, the 20th Century can best be seen as a combination of both American and British innovation, with American innovations being more prevalent and reported over. In the early 20th Century, Americans invented the first 'flying machine,' so to speak, thus bringing in the era of the airplane. Major American innovations of the period are quite easy to find. Now, the British had their day during WWII, successfully defending themselves against the German armies. The 20th Century really exemplifies cooperation between the two nations. During WWII bombing raids, the US bomber planes went by day, and the British by night, using both of the nations\' abilities to accomplish a common goal. The US went to the Moon, and created several new space technologies that brought new inventions to the scene. The British also had their share of accomplishments. The creation of a VTOL plane, defending themselves during the 'Battle of Britain,' taking the fight to them, fighting along side US forces all over the globe, and many others. However, neither side was perfect. The United States had a little fiasco called, 'the Vietnam War,' in which it basically repeated every mistake the UK made during the War for American Independence. There\'s also the matter of the nuclear bombs of Hiroshima and Nagasaki, killing millions over the next few decades. The CIA (US Intelligence Agency (no pun intended)) armed Afghan rebels (the precursor to the Taliban) against the Soviet Union, only to later have the nation turn against it. The British were not without fault either. The Irish rebellion is a gruesome reminder of the possibility of brutality by British forces. Then, there\'s the Bengal famine of 1943 (which England has yet to recognize), during which Winston Churchill ordered mass stockpiles of food and grain to be removed from the area in case of Japanese attack, killing between 3 and 9 million Bengali (estimates vary). As for language, both versions are correct. English is the main (or group) language, much as English is part of the larger Germanic (and Indo-European) language group. Beneath 'English' are various dialects that are all correct and should not be discriminated against. American English and British English (not 'true' English, as many tout) are both correct in their respective areas. Whatever words that are spelled differently are simply a matter of custom. Yes, many words were spelled 'incorrectly' in the first version of Webster\'s Dictionary, but Webster\'s personal accounts point to him wanting to create a national linguistic identity for the fledgling seaboard republic, and to help unify it, and separate it from England (contempt for England was pretty high in the early 1800\'s). However, soon enough these misspellings became common enough that when the accents changed, and various parts of syntax and grammar as well, American English became its own dialect. In essence, one cannot claim the superiority of one nation without having to look at that nation\'s faults. Both the United States and the United Kingdom have their virtues and vices, and both have their own manner of doing things. Whenever one does something, another does something else that helps to balance things out. American innovation is not playing catch-up to that of Britain, as many would claim. The US is the world\'s only superpower (China is not a superpower, get over it. Its far too self-destructive and unmanageable), and leads the world on many issues, to the disdain of those who don\'t. Yet Britain is also important. It has a massive history spanning millenia, and has had its own centuries to lead the world. Neither has been, is, or ever shall be perfect. The important thing, is that they are both together as brethren, and the citizens should be as well. Whenever a British person yells on the internet at an American, calling them 'fat; idiot american; etc.,' I am appalled, but I am just as equally appalled at Americans yelling British stereotypes. Hopefully, this makes it clear that neither nation is superior historically, and factually neither stereotype has any true ground (besides the obesity, buts a global epidemic. Although I will admit, McDonalds is the only thing you can forget to get on the exit for and say, 'Oh well, I\'ll get the next one. Its only a few yards away.').

I helped out quite a bit with certain subjects, and acted as a tutor on occasion. I also acted with superb character, with which I received the character award that school awards to two students every graduating class (the factors are character and academics).

Yes, that\'s correct. Wait, Oh God when did I get 1000 posts!?

Oman

Oh God no! (I can cope with ponies, but Dora pushes the limit). Someone who likes cheese.

Welcome to the team that has created the Game of the Millennium. I suppose the animated kerbals are the precursor to EVA\'s?

Endela

When you\'re willing to pay 60 USD to get the Roleplay forum as a PC game.

When your post count goes from 150 to 850 in the same month Roleplay posts are counted.

Two keyboards, and typing only with the right hand.

I believe Zoxygen would work quite well, actually.

I am interested as well. *Returns to underground research facility designing*

9/10 for a nice rocket, even if the icon next to it is an advertisement.

Hmm... a diamond wallet.

You have to click it, then move your mouse over the area you want to put it. Then, you have to scroll up circa 3 mouse rolls, and position it from the top. It has a very low origin, and so you must scroll up in order to see it in the VAB.

3/10, I cannot see a thing either, but at least you tried.

Well, everyone go outside! Despite it being an hour before midnight in my timezone, I went outside, and the ground is now diamond (I tripped).