The Earth Is Not Round. (Gravitational Field/without water)

originally posted by: Sublimecraft
I first learned about this at the Maritime college when studying Celestial Navigation - because the Earth is flattened at the poles and bulges at the equator, geodetics engineering represents the shape of the earth with an oblate spheroid

How oblate?

This isn't a hoax, this is a map of the gravitational field of the Earth. Here is an older map using GOCE data.


Direct link to video

By capturing the planet's gravity rather than its physical appearance, the geoid shows the shape that mean sea level would have if it could somehow be extended over the entire surface of the globe, said John Wahr, a geophysicist at the University of Colorado.

New Gravity Map Reveals Lumpy Earth

originally posted by: cmdrkeenkid
This isn't a hoax,

The thread title says:

The Earth Is Not Round.

That is the hoax. The Earth is more or less round.

a reply to: Arbitrageur

The thread title also states that it's pertaining to the gravitational field and without water.

Edit to add: The body of the post is even very clear about this. Not a hoax, not even misleading.

originally posted by: cmdrkeenkid
a reply to: Arbitrageur

The thread title also states that it's pertaining to the gravitational field and without water.

Edit to add: The body of the post is even very clear about this. Not a hoax, not even misleading.

What?????????

This is what the OP says, your statement completely false. This does not make that clear at all:

As seen without water (or looking at the gravitational field of Earth) the Earth is not spherical at all but a lumpy mass like a potato.

a reply to: Arbitrageur

You're entitled to your opinion. It was clearly stated in both title and body of the OP that this was a gravity map of the Earth. Both the links you and I provided explain geoids.

a reply to: cmdrkeenkid

Do you really think the OP is "not even misleading" when it says:

the Earth is not spherical at all but a lumpy mass like a potato.

Both the Earth itself and the Earth's gravitational geoid with or without water are much more closer in shape to a sphere than a potato. Are you seriously arguing it's more like a lumpy potato than a sphere and saying that is not misleading?

The potato shape is arrived at by exaggeration of the variances, depending on what illustration you look at it could be by a factor of 7000, so that's very misleading.

You could take a perfect circle, put 4 tiny bumps on it and it will look like a circle with 4 tiny bumps on it. If you then magnify the bumps by a factor of 7000 you could give the circle some other shape maybe more like a square. But altering your illustration by a factor of 7000 doesn't alter the actual object, an illustration showing a square-like shape would be a misleading illustration if the actual shape is a circle with 4 tiny bumps on it. This is what's going on with the potato shape being illustrated, it's a gross distortion of the actual shape of the geoid.

www.slate.com...

The actual graphic is hugely exaggerated on purpose, making it easier to see the Earth’s lumpy gravity field.

So it's not what the Earth would look like without water, nor is it what the Earth's geoid would look like without water, hence it's very misleading. It's the Earth's geoid, with minor deviations hugely exaggerated to the point of being misleading, especially if people actually believe the geoid is actually shaped anything like a potato.

You're entitled to your opinion.

Not opinion, fact.

I think the correct expalnation for the graphic is:

This is a scientific model made to measure gravity. It does not have anything to do with taking oceans away. It shows what the earth would look this lumpy only if you removed all of the factors that help shape Earth’s surface, such as tides, weather, and wind, which will reveal that gravity varies across the globe.

- www.sciencealert.com...


Maybe it will look more like something like this:





Not sure how accurate those models are. Interesting either way.

Considering the amount of water actually on the Earth, I don't imagine too much variation from it's average 'circumference'.

Supposedly it is not round but a slight geode or an ellipsoid.

"The shape of the Geode, as it is called, is nearly a perfect sphere, but because the earth is spinning, it is about 21.5 kilometers flatter at the poles, and bulged-out at the equator by about the same amount."

"The possibility that the Earth's equator is an ellipse rather than a circle and therefore that the ellipsoid is triaxial has been a matter of scientific controversy for many years" en.wikipedia.org...

There are plenty of dents in the fenders.
I think we would probably not have fared as well without the waters finding their levels.
Seems like a pretty nice planet to me.

originally posted by: nOraKat
Not sure how accurate those models are. Interesting either way.

As explained here, from the deepest ocean trench to the highest mountaintop, the smoothness of the Earth's surface would be within the tolerance for a billiard ball, and you can rest assured if those illustrations were the size of billiard balls they wouldn't be acceptably smooth for a billiards game, that should be obvious, right? The other thing that's self contradictory is that the amount of water shown relative to the size of the Earth is probably about right, but obviously that amount of water would not fill up the oceanic depressions shown, so we know they must be greatly exaggerated.

"The shape of the Geode, as it is called, is nearly a perfect sphere, but because the earth is spinning, it is about 21.5 kilometers flatter at the poles, and bulged-out at the equator by about the same amount."

"The possibility that the Earth's equator is an ellipse rather than a circle and therefore that the ellipsoid is triaxial has been a matter of scientific controversy for many years" en.wikipedia.org...

I searched that source "Figure_of_the_Earth" for the word "geode" and that word doesn't appear in that link. Geode is a type of rock and the first thing it says at that link is "Not to be confused with geoid." but I think you confused them.

The third wiki link about the "controversy" dates back to 1962, when we didn't have the satellite measurements we do now, so I would take that 1962 source as merely pointing out what wasn't known in 1962. We know much more today.

They can show you what it looks like without water but they cant show you how the earth would finally end up after adjusting without the weight of the water pressing down on it.

a reply to: Arbitrageur

Thank you. The image and thread title and op confused me. So I guess my last post is not very relevant then.

a reply to: 3n19m470
I think your graphic is relevant in the sense that the OP refers a graphic of exaggerations of variations in the Earth's geoid, and you posted a graphic of exaggerations of variations in the Earth's surface. In both cases the exaggerations are intentional because without them the shape we would see with the naked eye would be fairly spherical. As long as we understand the illustrations are exaggerated, the exaggerations may be useful, but I fear some people might take the exaggerations too literally and think that's what the earth's surface or the earth's geoid really look like when they are not accurate representations.

This is why I call this topic a hoax; the Earth's geoid is not shaped like a potato, as the OP claims. The illustration is shaped like a potato, but the illustration is not accurate.