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Satellites Solve Mystery Of Low Gravity Over Canada
New Scientist ^ | 5-10-2007 | Kelly Young

Posted on 05/11/2007 4:37:41 PM PDT by blam

Satellites solve mystery of low gravity over Canada

20:16 10 May 2007
NewScientist.com news service
Kelly Young

The GRACE satellites have detected changes in the gravitational field over regions of Canada that can be attributed to the crust bouncing back after the melting of a glacier 20,000 years ago and convection in Earth's mantle (Illustration: Science/M Tamisiea)

If it seems Canadians weigh less than their American neighbours, they do – but not for the reasons you might think. A large swath of Canada actually boasts lower gravity than its surroundings.

Researchers have puzzled for years over whether this was due to the crust there rebounding slowly after the end of the last ice age or a deeper issue involving convection in the Earth's mantle – or some combination of the two.

Now, ultra-precise measurements taken over four years by a pair of satellites known as GRACE (Gravity Recovery and Climate Experiment) reveal that each effect is equally responsible for Canada's low gravity. The work could shed light on how continents form and evolve over time.

GRACE, a joint mission of NASA and the German Aerospace Center, was launched into space in 2002. The two spacecraft fly 500 kilometres above the Earth, 220 kilometres apart. Using a microwave ranging system, the two spacecraft can measure distance differences between them as tiny as a micron.

That allows them to measure tiny changes in the distribution of mass – and hence gravity – on the Earth. For example, if the leading spacecraft were to encounter an area with more gravity, it would be pulled ever-so-slightly closer to Earth than the trailing spacecraft, and that distance can be measured.

Crushing weight

A team led by geophysicist Mark Tamisiea, who performed the work while at the Harvard-Smithsonian Center

(Excerpt) Read more at space.newscientist.com ...


TOPICS: News/Current Events
KEYWORDS: canada; gravity; lumpygravy; mystery; notamystery; potsdamgravitypotato; satellites
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1 posted on 05/11/2007 4:37:42 PM PDT by blam
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To: blam

2 posted on 05/11/2007 4:38:49 PM PDT by blam
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To: blam

Sooooooooo, are they saying Canada doesn’t suck as much as the rest of the world?


3 posted on 05/11/2007 4:40:07 PM PDT by null and void (The truth. It is a beautiful and terrible thing, and should therefore be treated with great caution.)
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To: blam

I thought it was due to light weight politicians.


4 posted on 05/11/2007 4:40:33 PM PDT by Paleo Conservative
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To: blam

Bush’s fault?


5 posted on 05/11/2007 4:41:30 PM PDT by Don Corleone (Leave the gun..take the cannoli)
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To: blam

We’ve known about the rising Canadian sheild for decades. It’s one of the reasons for the cliffs around lake Superior.


6 posted on 05/11/2007 4:42:43 PM PDT by cripplecreek (Greed is NOT a conservative ideal.)
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To: Don Corleone

Bushs fault and carbon emissions fault.


7 posted on 05/11/2007 4:44:38 PM PDT by Screamname (The only reason time exists is so everything doesn`t happen all at once - Albert Einstein)
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To: null and void
Come on girls! We're going to Canada to lose weight the easy way!

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8 posted on 05/11/2007 4:46:08 PM PDT by cripplecreek (Greed is NOT a conservative ideal.)
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To: blam

When they say they have several theories as to what is happening, it means they don’t really know what is going on.


9 posted on 05/11/2007 4:46:14 PM PDT by tet68 ( " We would not die in that man's company, that fears his fellowship to die with us...." Henry V.)
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To: Screamname
the crust bouncing back after the melting of a glacier 20,000 years ago

Global warming caused by those 20,000-year-old industries.

10 posted on 05/11/2007 4:47:11 PM PDT by JennysCool ("The urge to save humanity is almost always a false front for the urge to rule." -Mencken)
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To: Paleo Conservative

No, silly. It is because Canada is close to North Pole and that is how Santa’s raindeer fly. Pffft. Who needs scientists?


11 posted on 05/11/2007 4:47:50 PM PDT by myprecious
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To: tet68; blam
Everyone knows that because they make so many movies in Canada you have more Hollywood celebrities in the area.

Since you have so many Hollywood celebrities you have more Scientologists.

Since you have more Scientologists you have fewer Thetans.

Since you have fewer Thetans you have less gravity.

12 posted on 05/11/2007 4:51:03 PM PDT by Grizzled Bear ("Does not play well with others.")
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To: blam

Airheads?


13 posted on 05/11/2007 4:52:59 PM PDT by fish hawk (The religion of Darwinism = Monkey Intellect)
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To: blam

“can be attributed to the crust bouncing back after the melting of a glacier 20,000 years ago”

Wow, that is a really long bounce!!!


14 posted on 05/11/2007 4:56:36 PM PDT by treffner
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To: blam

Oh NO! Global Warming melts glaciers, and destroys gravity. We’re all going to float away!


15 posted on 05/11/2007 4:57:16 PM PDT by norwaypinesavage (Planting trees to offset carbon emissions is like drinking water to offset rising ocean levels)
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To: blam

So Canadians are lightweights? Figures.


16 posted on 05/11/2007 5:00:52 PM PDT by SampleMan (Islamic tolerance is practiced by killing you last.)
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To: blam
Recommended compensation:
17 posted on 05/11/2007 5:06:49 PM PDT by traumer
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To: norwaypinesavage
Oh NO! Global Warming melts glaciers, and destroys gravity. We’re all going to float away!

Don't be surprised if some global warming theologian actually makes that statement.

18 posted on 05/11/2007 5:08:09 PM PDT by jmyrlefuller
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To: blam

Hm...


19 posted on 05/11/2007 5:08:57 PM PDT by Tzimisce (How Would Mohammed Vote? Hillary for President! www.dndorks.com)
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To: blam

Interesting.


20 posted on 05/11/2007 5:11:37 PM PDT by FreeRadical (Pray. Make Babies. Teach. Repeat.)
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