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 ...
Only north of Lake Winnipeg, if you want the full no-suck effect. Of course, that would be one of the western provinces, not so close to Ottawa...
It’s all those hosers.
Ohhhh....
Does this mean my theory about more canuks smoking dope isn’t valid?
That’d be good enough for a couple of extra trips to Tim Horton’s, eh?
Soooo...does it follow that gravity is lower in San Francisco, too? Lot’s of folks are light in their loafers there.
OH No!!!!
LOL!!!!!!!
'Theologian' is waaaaaaaay too kind. Shaman is more appropriate. (NOUN: A member of certain tribal societies who acts as a medium between the visible world and an invisible spirit world and who practices magic or sorcery for purposes of healing, divination, and control over natural events)
Oh Happy Days!!!!
I understood what you said.
Your logic is brilliant and makes me jealous.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.