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'Potato' Earth's Deep Secrets (Gravity Map)
BBC ^ | 7-24-2003 | Jonathan Amos

Posted on 07/24/2003 5:44:37 PM PDT by blam

'Potato' Earth's deep secrets

By Jonathan Amos
BBC News Online science staff

It is a map the like of which you have probably never seen before.

Gravity highs are marked red; gravity lows are blue

The sweep of colours shows minute variations in the Earth's gravitational field.

If you were to fly over the red areas, you would be tugged ever so slightly downwards; the blues mark regions where the planet's attraction is much weaker.

These gravity anomalies, as they are known, are imperceptible to the human senses, and so the scientists have wrapped the data on to a sphere and exaggerated the highs and lows.

This gives us a stunning visual representation of the subject under study.

It might look a bit odd - but don't be fooled by this "virtual potato". The map and the others that will follow it are going to give extraordinary new insights into how the oceans move and influence the climate.

Understanding precisely how greenhouse warming could change our planet will depend on these bumps and pimples.

Sharp focus

The map has been produced by the US-German Gravity Recovery and Climate Experiment (Grace) mission.

This model is the first full science product to come out of the mission which gathers its data from two spacecraft orbiting more than 450 kilometres above the Earth.

One of the wedge-shaped twins in preparation prior to launch

The Grace twins, which were launched last year, are still being tested but already their gravity map easily surpasses the detail of any other previously obtained.

"I'd say this model is an order of magnitude more accurate than any of the previous ones built from satellite data," said Dr Byron Tapley, the principal investigator on the mission.

"In just 30 days, we collected enough information from Grace to improve what we'd done in 30 years by other methods by about a factor of 10. It's a dramatic improvement in what we know about the Earth and there is more to come," the University of Texas, US, researcher told BBC News Online.

The Grace satellites obtain their data by executing a carefully calibrated pursuit in orbit.

Mass movement

As one spacecraft lurches and drags through the Earth's uneven gravity field, the second follows 220 km behind, measuring changes in their separation to the nearest micron (a thousandth of a millimetre).

It is the size of those changes detected by the twins that describes the nature and scale of the gravity anomalies over which they pass.

GRACE GRAVITY MAP "It's a dramatic improvement in what we know about the Earth and there is more to come"

Enlarge Map

Obvious hotspots are discernible, such as the Himalayas where mass continues to increase - and with it gravitational attraction - as rock is piled into the region by plate tectonic movements in the Earth.

But it is in the fine detail that Grace excels, particularly with the oceans which are a constant shifting mass.

"The ocean's surface, while appearing flat, is actually covered with hills and valleys caused by currents, winds and tides, and also by variations in Earth's gravity field," said the US space agency's Dr Lee-Lueng Fu.

"Scientists want to separate out these gravitational effects, so they can improve the accuracy of satellite altimeters like Jason and Topex/Poseidon, which measure sea surface height, ocean heat storage and global ocean circulation.

"This will give us a better understanding of ocean circulation and how it affects climate."

Deep down

The first model produced from the Grace data is a static map - a snapshot of the Earth's gravity profile. But of course this profile is changing with the movements in the solid Earth, the oceans and the mass of the atmosphere on top of them.

So Grace, every 30 days, will send down new map data that will give a time-variable view of the gravity profile.

They will permit researchers to monitor changes - such as the major event in 1998 when satellites detected a sudden reversal in the shrinking of the Earth's girth that has been going on since the last Ice Age.

The probable cause was a surge in polar ice melting which, along with shifts in ocean circulation, sent a huge movement of water towards the equator.

"It's looking pretty certain that a lot of what was happening was due to something going on in the deep ocean," said Dr Chris Hughes, from the UK's Proudman Oceanographic Laboratory.

If it happens again, Grace will be able to provide more definitive answers.

"Grace allows us to see the parts of the ocean that are hardest to observe by any other method," said Dr Hughes, who will be using Grace to study deep circulation patterns.

"This is the only satellite technology that can actually see through the surface of the ocean; everything else gives you a measure of what's going on in the top metres.

"But with this, you actually see straight to the bottom."


TOPICS: Culture/Society; News/Current Events
KEYWORDS: astronomy; catastrophism; champ; deep; earth; grace; gravity; gravitypotato; potao; potsdamgravitypotato; science; secrets; techindex
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To: blam; *tech_index; MizSterious; shadowman99; Sparta; freedom9; martin_fierro; PatriotGames; ...
Nice picture!

OFFICIAL BUMP(TOPIC)LIST

21 posted on 07/24/2003 6:25:31 PM PDT by Ernest_at_the_Beach (Recall Davis and then recall the rest of the Demon Rats!!!)
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To: tscislaw
I did notice a serious, serious lack of gravity in the vicinity of France!
22 posted on 07/24/2003 6:26:56 PM PDT by Arkie2 (It's a literary fact that the number of words wriiten will grow exponentially to fill the space avai)
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To: SpaceBar
    bouger anomaly

Correctly put, that should be Bouger anomaly with the 'B' capitalized ...

23 posted on 07/24/2003 6:28:03 PM PDT by _Jim (First INDICT the ham sandwhich ... the next step is to CONVICT it ...)
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To: SpaceBar
Moreover, correctly spelled the term is Bouguer anomaly named for Pierre Bouguer, a French mathematician (1698 to 1758).
24 posted on 07/24/2003 6:31:33 PM PDT by _Jim (First INDICT the ham sandwhich ... the next step is to CONVICT it ...)
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To: Arkie2
>>...I did notice a serious, serious lack of gravity in the vicinity of France!..<<

Yeah, Frenchmen do seem to be a little "light in the loafers".

25 posted on 07/24/2003 6:39:33 PM PDT by FReepaholic (My other tag line is hilarious.)
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To: _Jim
Pierre Bouguer. You're putting me on, aren't you?
26 posted on 07/24/2003 6:41:42 PM PDT by fhayek
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To: fhayek
Ahhh .. yeah. I'm putting you on (like I know these things?) ...
27 posted on 07/24/2003 6:44:12 PM PDT by _Jim (First INDICT the ham sandwhich ... the next step is to CONVICT it ...)
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To: blam
Hildebeast could stand on a scale in the blue zones and still peg the meter.
28 posted on 07/24/2003 6:47:20 PM PDT by HighWheeler
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To: fhayek
Pierre Bouguer
29 posted on 07/24/2003 7:06:54 PM PDT by blam
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To: All

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30 posted on 07/24/2003 7:07:40 PM PDT by Bob J (Freerepublic.net...where it's always a happening....)
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To: blam; MeeknMing
COOL. Check this out, bro, I think the world is pullin' on me more than you...
31 posted on 07/24/2003 7:17:15 PM PDT by maxwell (That's DOCTOR Max to YOU, bud.)
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To: blam
Lucky guess on my part huh?
32 posted on 07/24/2003 7:17:58 PM PDT by _Jim (First INDICT the ham sandwhich ... the next step is to CONVICT it ...)
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To: maxwell; blam
Interesting, thanks ! I never figured such anomalies occurred with gravity.

33 posted on 07/25/2003 2:18:42 AM PDT by MeekOneGOP (Bu-bye Dixie Chimps! / Coming Soon !: Freeper site on Comcast. Found the URL. Gotta fix it now.)
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To: blam
Know if there is any matching of areas on opposite sides of the earth? Does low gravitational force in the Gulf of Mexico match a low density in Nepal?
34 posted on 07/25/2003 2:51:28 AM PDT by DPB101
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To: blam
Understanding precisely how greenhouse warming could change our planet will depend on these bumps and pimples.

I'm going to hurl...
35 posted on 07/25/2003 2:55:09 AM PDT by GodBlessRonaldReagan (where is Count Petofi when we need him most?)
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To: farmfriend
BTTT!!!!!!
36 posted on 07/25/2003 3:02:24 AM PDT by E.G.C.
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To: GodBlessRonaldReagan
Make sure you do that in a low gravity area.
37 posted on 07/25/2003 6:34:58 AM PDT by Arkie2 (It's a literary fact that the number of words wriiten will grow exponentially to fill the space avai)
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To: blam
Does this mean I should go to Cuba or Canada to lose those last 20 pounds?
38 posted on 07/25/2003 6:39:15 AM PDT by hispanarepublicana (successful, educated unauthentic latina--in Patrick Leahy's eyes, at least)
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To: Arkie2
I've noticed a disturbing gravity high always in the vicinity of good bourbon.

You too? I've noticed a high-gravity cell in my den, concentrated around the area where my reclining sofa is, and the problem seems to be compounded by the introduction of a Bloody Mary or other Polish vodka-based libation. I need millions in Federal grant money to further study this phenomenon...

39 posted on 07/25/2003 6:43:56 AM PDT by HenryLeeII
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To: 75thOVI; Abathar; agrace; aimhigh; Alice in Wonderland; AndrewC; aragorn; aristotleman; ...
Note: this topic is from 7/24/2003. Thanks blam.
See the keyword potsdamgravitypotato for more.

40 posted on 07/05/2018 10:04:45 AM PDT by SunkenCiv (www.tapatalk.com/groups/godsgravesglyphs/, forum.darwincentral.org, www.gopbriefingroom.com)
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