Science / Science and Communication

Is the Earth shaped like a potato – Science in social media

In answer to the question posed in this blog post’s title:

Short answer – No.

Long answer – A big, unequivocal, starchy, no.

Take a quick romp around the internet, however, and you may be surprised to find that there are a myriad of sources that may say (either directly or indirectly) that our planet in fact has lumps and holes just like that popular tuber.

potato earth

 

When I first scrolled past this post on my dashboard, the look on my face could have been mistaken for an Edvard Munch painting. Of course the Earth isn’t a perfect sphere.† But lumpy?  A POTATO? No. Who made this? There had to be something I was missing. After a cursory google search, I find that the image in question was not, in fact, a model of the earth sans water, but a representation of the Earth’s gravitational potential. Also an interesting concept, but entirely different.‡

But there’s a larger issue here. When you look at the post above, your first thought may be, “Megan, why do you follow a blog by the name of 12-Gauge-Rage with sub-pages labelled ‘Guns’ and ‘Cars?’” And that’s a valid question. I don’t. Which leads me to what might be your second question, “Who really saw this and believed it anyway?”

notespotatoearth

 

The notes on this post, that is, how many times the post was wither liked or reblogged, is over 300,000 at press time (ha! I get to use phrases like “press time”). Even if we assume that a third of these notes were from bloggers refuting this potato-earth claim, it’s scary to think that 200,000+ saw this post, and now believe this is what the Earth looks like. Now, I don’t know where this person initially got this graphic. I do know that a similar image, albeit a little more famous (the Potsdam Gravity Potato) was featured as NASA’s Astronomy Picture of the Day on the 14 of December last year with almost no context. There is a good explanation of the figure in its caption, but for an outreach venture whose main purpose is to disseminate a picture, the fact that there is absolutely no title, colorbar, or framework on the image itself is troubling.

Potsdam Gravity Potato

Courtesty NASA AotD: NOT A REPRESENTATION OF THE ACTUAL SHAPE OF THE EARTH

 

Now, I’m not saying that a scientist should be held completely responsible for the interpretation of any figure she makes and uses to visually represent her research. Actually. That’s exactly what I’m saying. If anyone besides fellow earth scientists looks at the image of the Potsdam Gravity Potato and doesn’t think, “Oh, so that’s what the Earth actually looks like!” show them to me and I will give them a cookie. Clarity is one of the first –and most consistent – things we learn in science classes – label your axes; what units did you use; choose a reference frame. In social media, one of the emerging vanguards of science communication, I would argue that transparency is even more important than simplicity. It doesn’t matter how easy a concept is to understand, if you’re understanding the wrong thing. And especially in social media, where the content creators are not always primary sources, it can be essential. I’m all for creating dynamic and visually arresting representations of data in order to illustrate a point, to make research more compelling, or even to simplify a concept. But if it turns into a misrepresentation, it can be downright dangerous to the field of science communication as a whole.

 

 

†It’s actually an oblate spheroid. QUADRIC SURFACES OH YEAH

‡The gravitational potential of Earth varies at different points on the planet. Gravitation is dependent on mass of the planet, mass of the object, and distance of the centers of gravity of each of these objects to each other. These things are obviously not constant. You change your distance to the center of earth whenever you change your elevation. Your gravitational potential in Death Valley, CA (elev. 86 meters below sea level) will be different than your weight on K2(elev. 8,611 meters above sea level). The mass of the Earth is also not evenly distributed. If the density of the amount of earth between its center and your center is very high (like if there was only a thin layer of continental crust, but a thick layer of liquid outer core) there will be more gravitation than if the density is very low. So a seemingly contradictory effect of this, is that on a really tall mountain, you are farther away from the Earth’s center, resulting in a lower gravity. You are also standing on a relatively thicker layer of crust, meaning that, all else being equal, there is more mass of dirt between you and the center, resulting in a higher gravity. The potato-earth attempts to represent these gravitational fluctuations in a visual way. The red areas are spots where gravity is relatively high, and the blue areas where it is relatively low, in effect showing what your relative weight might be at a particular location.

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2 thoughts on “Is the Earth shaped like a potato – Science in social media

  1. Pingback: The Random Things I Learned Today Thread - Page 32

  2. Pingback: Megan Schutt: Our Renewable Energy | UNder the C

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