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RJG2 writes
"MSNBC has an article stating that Earth's gravitational field has changed, becoming stronger towards the equator, thus becoming flatter. The cause has yet to be determined, but it is assumed changes in ocean levels are responsible."
Flat Earth Society (Score:2, Funny)
Re:Flat Earth Society (Score:1)
If Global Warming is true, then... (Score:1, Interesting)
Re:If Global Warming is true, then... (Score:3)
Where does the melted ice go? -> equator.
What makes gravity? -> mass.
More mass at the equator means more gravitational force.
Only the Ice at the south pole (Score:2)
the Ice at the north pole is floating, mealting it won't change the sea level.
You can try this out at home with an ice cube and a glass of water.
Put some water into the glass.
Then put an ice cube in the glass.
Mark the water level at the side of the glass.
Wait for the ice cube to mealt.
Check the water level in the glass!
Nope, it flows to the equator (Score:3, Informative)
Actually one likely side-effect of long term global warming is, ironically, an ice age. The water moves to the equator, and this causes the earth to spin slightly slower. The side-effect being that this cools the earth. I forget exactly why this is because I learned it in high school physics which was just over a decade ago.
Re:Nope, it flows to the equator (Score:4, Informative)
Since the earth is spinning, the water tends to be forced to the equator by centrifugal force (although I think more correctly it's centripedal force, but whatever).
IMHO, high school physics teachers really dropped the ball in explaining this one. A whole generation of high school graduates is confused about centrifugal vs. centripedal.
A body that is spinning around an axis or orbiting around point must be under continual force. Otherwise, they would simply fly off in a straight line at a tangent to the curve. This is the centripedal force. The centrifugal force is a "pseudo force", which means that it only exists in a non-intertial frame of reference.
Basically, what happens is that when you accelerate (whether in a straight line or in a circle), your inertia feels like a force in your frame of reference. When you sit in a moving car, from your point of view you feel like you are sitting still and the car is moving. We know that when an object is at rest, the forces on it are balanced. Therefore, in your frame of reference you feel a pseudo force which balances out the force that is being applied on the car. The pseudo force is really just the effect of your inertia.
So how does this apply to the water? Well, everything on Earth has inertia, and this inertia wants to keep it going in a straight line, even though the Earth is rotating. Solid objects, such as humans are obviously kept in place by simple static friction and wind resistance. Water and air are more mobile and they are less subject to friction (although they are still very subject to air/water pressure). That is the main reason why wind and ocean currents are very obvious whereas continental drift takes centuries.
So in reality, it is the inertia of the water that makes it more buoyant at the equator. The water at the equator is spinning faster than the water at the poles, so it is slightly less subject to gravity. Therefore it bulges out, "making room" for some extra water from the poles to move towards the equator.
-a
Yo mamma (Score:3, Funny)
Yo mamma so big that... n/m
Re:Yo mamma (Score:2, Funny)
Re:Yo mamma (Score:2, Funny)
This reminds me. (Score:2, Interesting)
Re:This reminds me. (Score:4, Funny)
Re:This reminds me. (Score:2, Funny)
Sorry....
Re:This reminds me. (Score:1)
Shorter and Fatter (Score:5, Funny)
Mid life crisis? (Score:4, Funny)
Actually its pretty scary... (Score:5, Interesting)
There appears to be a movement of a huge mass from the poles to the equator over the last 4 years. The article describes how they excluded the obvious culprits: melting ice, earth movements, atmosphere etc. And finally concluded that it is related to ocean circulation. Now that gives me the creeps!
Why the creeps? Because ocean circulation changes can happen relatively quickly and are implicated in the starting / stopping of ice ages. They are crucial indicators for climate change. And when the ocean circulation changes there is nothing humans can do about it.
Hopefully it either isn't the oceans or if it is it wont have a serious effect (dont believe my own words here ... but it sounds comforting). Whatever, this requires some serious investigation, just hope they got it wrong.
Re:Actually its pretty scary... (Score:2)
Re:Actually its pretty scary... (Score:2, Funny)
I sure hope not. Wouldn't want to see everything on the surface of the planet suddenly fly off into space....
Re:Actually its pretty scary... (Score:2)
Don't panic yet. Life is resilient and humans are resilient.
Given enough time, we'll eventually develop the technology to fix our climate where we like it. (Which will probably spark heated debates about where to set the global thermostat.) And in the interim, there's no good reason to panic.
Re:Actually its pretty scary... (Score:2)
Why are you more worried about ocean circulation than melting ice, atmoshperic changes, etc.? We can't do shite about any of them...
Re:Actually its pretty scary... (Score:2)
I have to disagree here. There has to be something we can do about it- it may be expensive, it may require a hell of a lot of research and maybe some geo-engineering with 100 megaton bombs or other "long levers", but imho it seems silly to think that we can be currently unconsciously changing the world's climate on one hand (greenhouse effect) and yet be completely unable to consciously change it back.
Good Ol' Gaïa (Score:1)
Re:Good Ol' Gaïa (Score:2, Funny)
Awesome! (Score:3, Funny)
-S
Re:Awesome! (Score:2)
There are two competing factors, the force away from the center of the earth caused by the Earth's rotation, and that of gravity. The Earth is about 15km different in diameter from poles to equator, with the equator being further away than the poles. While it might be true that the Earth's gravity field (the gravitational equipotential field, or the "geoid" I believe) has been getting flatter, it still isn't round. While I haven't checked the equations lately, I think gravity still wins out over the rotational part, and you'd be _heavier_ when you moved to the poles, due to being in closer proximity to the center of the earth.
Re:Awesome! (Score:2)
Are there actually any people south of the equator anyway?? I know there are some over in that place they call Europe, but actually _south_ of the equator? Come on! They probably just _look_ human, you know, like Martha Stuart.
Re:Awesome! (Score:2)
It's the Ab Roller! (Score:1)
Re:Actually, no... (Score:2)
Re:Actually, no... (Score:2)
Re:Actually, no... (Score:2)
Since we're not experiencing shorter days, and my ever-increasing weight indicates the earth's attraction for me is not lessening, I suspect that's not the cause. Besides, we're talking about a flatter gravitational field, not a flatter earth.
Sweet spots? (Score:1)
Re:Sweet spots? (Score:2)
Discovery of the location of the "sweet spot" is left as an exercise for the reader, or a student of freshman college physics.
Computer populations (Score:1)
Re:Computer populations (Score:2)
That might explain why Linux hasn't done well on the desktop market...
earth getting fatter (Score:2, Interesting)
Re:earth getting fatter (Score:2)
Could it help science? (Score:1)
I mean, sometimes it's easier to observe something which have variable input-output then observing something which is constant. At least when you have some control over the input/outpout part.
But if they can manage to determine exactly what input on earth has changed which could impact gravity, could it help them find what is gravity? Any physicist out there more knowledegable then me? (There sure is, I'm not even a physicist...)
Earth's getting flatter (Score:1)
Whew! (Score:4, Funny)
And maybe the shrinking waistband in all my pants is due somehow to the warping effect the extra gravity is having on space?
Change In Time? (Score:5, Interesting)
I expect so.
Re:Change In Time? (Score:2)
A reference on leap seconds (Score:5, Informative)
At first, I did not believe that such a small change could account for the leap seconds, but you're right [navy.mil]:
Re:A reference on leap seconds (Score:3, Funny)
tidally locked (Score:2)
Eventually, one side of the Earth will end up facing the Sun constantly. However, it'll take a very long time.
You both have your math wrong (Score:2)
That sentence can mean many different things. It is true that the our days are curerntly slightly shorter than 86,400 seconds, and 365 times that difference adds up to about one second, but that has nothing to do with whether the days are now getting longer or shorter. The duration of one rotation of the Earth on its axis is not getting shorter by one second every year. It is getting longer by 1.4 milliseconds every century, and I would guess that that deceleration will be weaker as the Earth slows down and the moon gets farther away.
Slight correction to my own posting (Score:2)
Re:Change In Time? (Score:2)
True, but like everything, the earths rotation is more complex. Every once in a while a storm get enough wind to speed things up. (And presumably the reverse happens too) Thats why the leap seconds don't happen with any pattern.
Re:Change In Time? (Score:2)
No. Thats a misunderstanding. The earths is slowing down. But this is measured in milliseconds pr century and is completely negligible in this context.
The reason for the frequent insertions of leap seconds is that the definitions of the time-span of a second and our definition of the length of a year (in seconds) don't match up. If we adjusted our definition of a second just a little bit we could tune the length of a second to make it fit our definition of the length of a year, and then we only needed to make a correction once a century.
Re:Change In Time? (Score:2)
Re:Change In Time? (Score:2)
And how much will our future space elevators slow the Earth over time? These equatorial spokes won't be very massive but they'll extend thousands of kilometers like giant arms, and additionally, Earth'll lose momentum for every unit of mass that never returns to the surface.
I'm sure it'd still be a miniscule but measurable effect.
But hey! We could always attach giant solar sails to the ends of these spokes such the sun's solar energy would "spin" the Earth back up to equilibrium. :-)
--
Re:Change In Time? (Score:2)
BUT, to get an idea of the size of the earth, if you were to draw a big circle on a piece of paper, the crust of the earth, the part we spend all our time on and haven't ever drilled through even half of it, would be over represented by the thickness of the line. (Crustal thickness on average is say 40 Km, the earth is 6371 Km in diameter, that's about
And even if we don't ever get the weight back from space elevators, I bet the time integrated weight of all the space dust and meteors we sweep out of space over millions of years would offset it.
Anyway, I just don't think most Slashdotters understand the magnitude of the volumes and forces they are talking about. The tidal forces of the moon are much more significant, and even that's barely measurable integrated over very long time periods.
But what the hell. I'm a geophysics grad student, and am probably a little over anal about these things.
Re:Change In Time? (Score:3, Interesting)
Re:Slower rotation means.... (Score:2)
I could certainly use sleeping in a 36 hour day... Too bad daylight will last longer too ;) and latenite coding will be overwhelmingly long.
But by then, so many years will have passed that computers will be the ones coding and passing out to keep us alive, à la Matrix
Back to the Future quote (Score:5, Funny)
Ocean levels? (Score:3, Interesting)
Considering that I live at an altitude of 20 feet and one mile from the ocean, I would think I would be one of the first people to know if the ocean level was changing. From what I can tell, the level of the Pacific Ocean is still the same as it was when I was a kid.
Re:Ocean levels? (Score:2)
If you were in an area that goes up only, say, 1/10th of an inch a year, your 'the level of the sea hasn't changed' observation would mean that the sea level has, in fact, gone up 2 inches (let's assume you were a kid 20 years ago)
Re:Ocean levels? (Score:2)
Yeah, but the Atlantic is way higher.
Re:Ocean levels? (Score:2)
Derek
Re:Ocean levels? (Score:2)
Re:Ocean levels? (Score:2)
Global warming won't kill us, but it is a royal pain in the ass.
It's the SHAPE, see Net Scientist (Score:2, Informative)
http://www.newscientist.com/news/news.jsp?id
The MSNBC report is misleading - the measurement (by satellites)is of gravity, but the conclusion is about the shape of the planet. The prime suspect, currently, is ocean currents.
Ask my ex workmate, it's the NT7 :) (Score:4, Funny)
Re:Ask my ex workmate, it's the NT7 :) (Score:2)
=Brian
Does this mean (Score:2, Funny)
State borders? (Score:3, Funny)
~N
Re:State borders? (Score:2)
At least they didn't shell each other over the border dispute, that could get real messy, what with all the BMWs and cellphones around.
Climatology models (Score:2)
earth's rotation -> length of day -> amount of axial wobble change -> seasonal azimuth -> earth climate?
And if gravity is higher at the equator - won't this affect time, since time slows down in a higher gravity field?
I'm sure that these changes are all rather insignificant taken separately, but taken together, doesn't this have an impact on accuracy of scientific measurements? Will everything need to be recalibrated?
Re:Climatology models (Score:2)
Re:Climatology models (Score:2)
But that's just us. The planet as a whole has indeed been through far worse and emerged unscathed.
Re:Climatology models (Score:2)
However, you are very wrong about the normal variablity of sea level. The level of the Earth's oceans are _not_ the same level all over the world. Due to gravitational anomalies, wind, rotation of the earth, etc., you could raise the level of the ocean in some places quite a bit and never see it in other areas. The greatest variablity comes from temperature differences. Average sea level change has been measured to be as much as 40 cm in some places, and we haven't been measuring for that long. It is very possible to get higher anomalies. The area around Florida gets annual changes of at least a couple cm.
So, I will retract my rather hasty "meters" in my quick response, but you will forgive me if I don't worry about change of a couple cm, as I would have to head for the hills on a very regular basis.
Perhaps you meant integrated over the whole globe perhaps?? That would be disturbing. However that was certainly not the type of anomaly the article was referring to.
Re:Climatology models (Score:2)
Yeah. If the ocean goes up in one place and down in another, big whoop. But up everywhere...
Re:Climatology models (Score:2)
What am I supposed to do? (Score:2)
I'm serious here! WHAT THE HELL AM I SUPPOSED TO DO WITH THIS INFORMATION?!? I feel like this should be huge or something but I just don't have any kind of context for this. I'm just going to act like I didn't read this article, and maybe get back to work.
I think I need a drink, I'm leaving early today.
Re:What am I supposed to do? (Score:2)
For instance, the Earth's gravitational field takes a big dip right over India. Why? Hell if anybody knows besides "there's a density anomaly in the mantle under India". The magnetic poles of the earth flip every tens of millions of years or so.
I can drone on for a while if you want, but I think you get the picture.
The whole thing is interesting to geophysicists, but it doesn't do anything to effect everyday life.
Feel safe. Go back to coding or whatever. Have a beer.
Re:What am I supposed to do? (Score:2)
Is binge drinking sort of a hard re-boot for the brain? Does excessive beer equal ctrl-alt-delete in a neural sense? I'll tell you tomorrow.
Re:What am I supposed to do? (Score:2)
As far as the movie B.S. goes, how about something like "Honey, at those temperatures and pressures, diamonds flow like plastic. I don't think those steel drill bits would do the trick."?
See previous article. (Score:2)
dude (Score:2)
True visionaries (Score:2)
round or flat? (Score:3, Funny)
The Scientist Who Cried 'The Sky Is Falling!!!' (Score:2)
Take cover! (Score:2)
DiscWorld (Score:2, Funny)
Re:DiscWorld (Score:2)
in related news (Score:2)
.
What a line (Score:2)
Huh. I thought that was a line that was only used in Hollywood. Not only that, but it is so unbelievable that a real scientist would ever say such a phrase that I have to assume that this isn't real. Either this is an elaborate hoax, or this is all a Hollywood movie that has been kept secret from us for all these years, a la The Truman Show. Whichever, my advice is to "Hold on to your butts."
For those who were wondering, it's a joke.
Re:Magnetic Pole Changing (Score:3, Funny)
Re:Magnetic Pole Changing (Score:2)
Re:Magnetic Pole Changing (Score:4, Interesting)
Assuming you believe all that, of course. As far as I know it's just a theory.
Re:Magnetic Pole Changing (Score:2)
I hate to be pedantic (aw, who am I kidding, I love being pedantic), but in general, saying "it's just a theory" is... well... not a good idea. (The page you referenced has a lot of bullshit new-agey stuff about higher dimensions and so on, but that's neither here nor there. Remember, "newage" rhymes with "sewage".
To a scientist, a "theory" is something that explains all or most of the known evidence, is well-supported by facts, and makes testable predictions. Many well-established things like universal gravitation, aerodynamics, thermodynamics, and so forth, are all "theories".
The word you're probably looking for is "hypothesis", which means "an idea that potentially explains the facts, but isn't yet well-supported and well-tested enough to be considered a theory."
Of course, it's a pretty smooth continuum between the places where an idea is considered a "hypothesis" and where it becomes a "theory" but dismissing a scientific theory as "just a theory" is misguided at best.
Hope that helps, somehow. Check out http://phyun5.ucr.edu/~wudka/Physics7/Notes_www/n
Ummm. no. (Score:3, Interesting)
Perhaps if the moon had suddenly increased in mass a thousand-fold, but not possible due to distant stars or planets.
Re:Ummm. no. (Score:2)
Re:It's also getting fatter! (Score:2)
Re:All those dang asteriods (Score:2)
That could really, really screw us up and for a long time too. Imagine if all those asteroids suddenly had their courses changed.
Bah, I'm blaming all this paranoia on too much diet coke, heh.
Re:All those dang asteriods (Score:2)
Re:Awesome (Score:2)
Re:Correllation is not Causation! (Score:2)
Dianetics by L. Ron Hubbard
Re:Magnetic Pole Swap (Score:2)
There is some speculation that nuclear forces in the deep center that power the magnetic fields may be on their last leg, and that they might run out any time now, exposing the earth to deadly cosmic rays by lowering the magnetic "sheild" that surrounds the planet.
However, the consensus is that we have another billion+ years before that happens.
Besides, the Sun is gonna heat up soon anyhow.
The Earth is in its late 50's WRT useful lifespan. Lets just hope it does not want to retire until we do (or we move off).