Newsy2011.4.5---地球重力圖

pp

Multisource political news, world news, and entertainment news analysis by Newsy.com

=================
Newsy2011.4.5---地球重力圖
Earth's Gravity Map Unveiled
You're watching multisource science news analysis from Newsy
The European Space Agency has released a 3D model showing just how lumpy Earth's gravity is. The data come from two years of observations by the GOCE satellite.
The model shows what the Earth would look like if the surface were fluid and gravity were the only force shaping it. It's a shape geophysicists call a geoid, and this particular geoid is the most precise gravity map ever made of Earth. (Video source: European Space Agency)
The gravity differences are magnified to make them easy to see. Still, the model doesn't look like the perfectly round globes we're all used to. Scientific American explains why the geoid is so lumpy.
"There are many reasons why the geoid isn't a sphere. First and foremost, the Earth itself isn't a sphere. ... But the planet isn't an ellipsoid either, because of topography. Mountains and valleys are asymmetrical distributions of mass. That mass distribution affects the gravitational field and makes the geoid asymmetrical too."
A major goal of the research is to build a shared reference for what we mean by "height." Each country measures sea level using local bodies of water, but since gravity distorts the shape of the oceans, it's hard to translate from one system to the other. Discover Magazine's Phil Plait says GOCE fixes the problem.
"It's the ultimate 'sea level'. This may seem esoteric, but this knowledge is actually important. For one thing, it gives a standard reference for topographic maps. For another, it will help scientists better understand ocean currents, circulation, sea wave heights, and other tricky measurements."
Scientists can compare this map of where the oceans should be to where they actually are. Studying the differences will help them understand how the ocean works. But the BBC says oceanographers aren't the only ones after GOCE's data.
"Those interested in earthquakes are also poring over the Goce results. The giant jolt that struck Japan this month and Chile last year occurred because huge masses of rock suddenly moved. Goce should reveal a three-dimensional view of what was going on inside the Earth."
The BBC link has a geoid you can spin yourself, so you can check whether you live in a high or low gravity area.
'Like' Newsy on Facebook for updates in your news feed
Get more multisource video news analysis from Newsy

地球的重力圖亮相
你看多源科技新聞分析Newsy
歐洲航天局發布了一個三維模型，顯示是多麼粗笨的地球引力。這些數據來自二年戈觀測的衛星。
該模型顯示了地球的樣子，如果是液體的表面和重力塑造了它的唯一力量。這是一個所謂的大地水準面的形狀地球物理學家，這特別是最精確的大地水準面重力圖有史以來地球。 （視頻來源：歐洲航天局）
重力差異被放大，使它們很容易看到。儘管如此，該模型看起來不象是完美的圓形地球儀我們都習慣了。科學美國人解釋為什麼大地水準面是如此的塊狀。
“有很多原因，大地水準面，是不是一個球體。首先，地球本身不是一個球體。...然而這個世界不是一個橢球要么，由於地形地貌。山脈和山谷的分佈是不對稱的大規模。，大規模分佈影響地球重力場和大地水準面不對稱使了。“
一個主要的研究目標是建立一個共同的參考就是我們所說的“高度”。每個國家的措施海平面利用當地機構的水，但因為重力扭曲的形狀海洋，很難從一個系統轉換到另一個。探索雜誌的菲爾普萊戈說，解決該問題。
“這是最終的'海拔'。這看似深奧，但這種知識是真正重要的。一方面，它給出了一個標準的參考地形圖。另一方面，這將有助於科學家更好地了解洋流，流通，海浪高度，和其他棘手的測量。“
科學家們可以比較這個地圖在哪裡海洋應該是他們實際上是。學習差異將會幫助他們了解如何海洋工程。但英國廣播公司說，海洋學家不是唯一的後 Goce的數據。
“那些在地震中也有興趣在鑽研戈結果。巨人震動本月襲擊日本和智利去年發生，因為群眾的巨大岩石突然感動。戈應揭露一個三維視圖是怎麼回事地球內部“。
英國廣播公司鏈接有一個自己的大地水準面你可以旋轉，這樣你可以檢查你是否生活在一個高或低重力區。
就像'Newsy在Facebook上更新您的新聞供稿
獲得更多的多源視頻新聞分析Newsy