This globe—the BBC has a spinnable version—shows you how the strength of gravitational pull differs in different places around the Earth. The yellow areas were where gravity is strongest. The blue spots is where it is weakest.

The picture you see here isn’t meant to be a totally accurate representations, it’s just meant to get across the simple idea of differences in gravity, separate from other planetary systems. The BBC describes the finished product as looking something like a potato.

Technically speaking, the model at the top of this page is what researchers refer to as a geoid. It is not the easiest of concepts to grasp, but essentially it describes the “level” surface on an idealised world.

If you were to place a ball anywhere on this potato, it would not roll because, from the ball’s perspective, there is no “up” or “down” on the undulating surface. It is the shape the oceans would adopt if there were no winds, no currents and no tides. The differences have been magnified nearly 10,000 times to show up as they do in the new model.

Even so, a boat off the coast of Europe (bright yellow) can sit 180m “higher” than a boat in the middle of the Indian Ocean (deep blue) and still be on the same level plane. This is the trick gravity plays on Earth because the space rock on which we live is not a perfect sphere and its interior mass is not evenly distributed.

Continued here:
Mapping the pull of gravity on Earth

Is the Paleolithic Diet—the fad regimen that suggests we should all eat more meat and no grains, ostensibly mimicking the diets of our ancestors—really healthy for the average human living today? Is it even actually representative of what human ancestors ate? Good tackles these questions and more, in a round-table interview with a group of anthropologists and evolutionary biologists.

Taken from:
Does the Paleolithic Diet make sense?

My new Publishers Weekly column has just gone up, documenting the progress with my DIY short story collection, With a Little Help. This month, I talk about the Baroque process of getting a book listed on both Lulu and Amazon:

Getting the book on Amazon was much harder than I anticipated. At first, I considered selling the book using Lulu’s wholesale channel, which can feed into Amazon. But once both Lulu and Amazon had taken their cut of the book, my net price would have been in nosebleed territory, somewhere in the $20 range. Add to that a $2 royalty for me and the book would be remembered as one of the most expensive short story collections in publishing history.

In order to list on Amazon at a decent price point, I needed fewer wholesale discounts. For me, that meant cutting out Lulu and listing directly on Amazon through CreateSpace, Amazon’s own POD program. But CreateSpace, frankly, is a pain in the ass. First, it refuses to print any book that already has an ISBN somewhere else, a very anticompetitive practice. To overcome this, I had to create an “Amazon edition” of the book with a slightly different cover and some additional text explaining the weird world of POD publishing.

But the fun was just beginning. CreateSpace also has a cumbersome “quality assurance” process that effectively throws away all the advantages of POD. For example, every time I change so much as one character in the setup file, CreateSpace pulls the book out of Amazon. A human being must recheck the book, and then I am notified that I have to order (and pay for) a new proof to be printed and shipped from the U.S. to London. I then have to approve the proof before CreateSpace will notify Amazon that the book is ready to be made available again. It can then take three to five days before the book is actually back for sale on Amazon. Practically speaking, this means that fixing a typo or adding an appendix with new financial information costs about $20 upfront, and takes the book off Amazon’s catalogue for two weeks.

With A Little Help: Hitting My Stride