Science Made Cool

The Biology of Lilliput

I recently posted a brief rant about Gulliver's Travels on my other blog, and it reminded me of an unpublished nonfiction piece I wrote about the biomechanics of Lilliput. Here are a few things Dr. Lemuel Gulliver failed to notice while in that kingdom (or maybe he just forgot to put them in his book):

The Absence of Stairs
Lilliputians don't need staircases. They can simply jump from one floor to the next. Here's how: muscular strength is proportional to the cross-sectional area of the muscles, as is bone strength. Weight is proportional to the volume of the body. So strength is in the proportion of 1/N², where N is the scaling factor, while weight is in the proportion  of 1/N³. Divide strength by weight and you get a jumping height of N.

According to Gulliver the Lilliputians were 1/12 the height of Englishmen, so N=12. That means a Lilliputian is 1/144 as strong as Gulliver, but weighs 1/1728 as much. The Lilliputian can jump proportionately 12 times longer, but since he's 1/12 Gulliver's size it cancels out. Gulliver and the Lilliputian can jump the same height in actual inches. If we assume Gulliver can manage a 1-foot standing jump with little effort, then so can the Lilliputians -- and that means they can easily jump up to the second story of their homes!

Getting down is even easier -- just step out of a window. Terminal velocity for a Lilliputian is proportional to the square root of mass over area, which means a Lilliputian's maximum falling speed is about 56 miles per hour in air. However, a Lilliputian's greater strength-to-mass ratio should mean they can handle high-speed landings more easily. If the factor of 12 holds for landing speed, then for a Lilliputian, a fall of any height is roughly the equivalent of Gulliver dropping about a foot.

Of course, Lilliputians can also carry immense-looking burdens. A fairly burly adult Lilliputian weighs about 2 ounces. He can comfortably carry four times that!

The Immense And Frequent Meals
The Lilliputians need to be able to carry big loads because they're going to be moving a lot of supplies to feed themselves. If we assume their body temperature is comparable to Gulliver's, they've got only 1/1728 as much heat-producing body mass and 1/144 as much surface area -- in other words they're losing heat 12 times as fast! It's a good thing Lilliput is in a fairly warm part of the world. Still, the inhabitants probably dress warmly at all times, and keep fires burning even in summer.

Even so, they're going to need a lot of food. A Lilliputian needs about 13 food calories (kCal) per day. Even if they stick to high-energy foods they're going to need about six meals a day just to get around the limits of their tiny stomachs. No wonder the twin kingdoms of Lilliput and Blefuscu are constantly at war -- they're both desperate for enough food to support their people!

Lilliputian agriculture must focus on high-energy foods -- lots of nuts, lots of sugar, lots of meat and dairy products. I doubt Lilliputians consider leafy vegetables to be food at all, and would only eat grains and starches in the direst conditions. It also seems likely that Lilliput and Blefuscu rely heavily on seafood, especially if they can land "giant" normal-sized fish. A single mackerel would feed 150 Lilliputians!

This also means that feeding Gulliver wasn't quite as tremendous a task for the Lilliputians as it might seem. Sure, he's a giant, but he only eats as much as a hundred Lilliputians -- and he's happy with barely-edible stuff like bread and potatoes.

The Short Lives
There's a rule of thumb in biology that most creatures get about a billion heartbeats, and that an organism's heart rate scales with its linear dimensions. So unfortunately the Lilliputians can expect a lifespan of no more than eight years, with the average closer to five or six. Gulliver noticed that the Lilliputians used months as their standard measurement of time, but evidently he got confused about that when recording how long the Emperor of Lilliput had been on the throne.

Lilliputians are probably mature adults at the age of 1 year. They undoubtedly have a lot of children, especially since gestation is likely only 23 days (which is comparable to that of rats). Because of their sensitivity to cold, I expect most young Lilliputians are born in the warmer months of the year, and the adults use contraception or practice rigid abstinence during the winter. Gulliver doesn't mention it, but there may be a drop-off in sexual activity during cold weather.

Their short lives and large appetites may also explain some of the social phenomena described by Gulliver. To Lilliputians, short-term gain is all that matters. There really isn't much point in planning beyond the next winter. Their quarrelsomeness and pettiness are a rational response to their biology.

It's Beginning To Look A Lot Like . . . NORAD

In just over 6 hours, as I write this, the phased-array radars and Keyhole look-down satellites of North American Air Defense Command will begin performing the task for which they were really created -- you didn't fall for that whole "Cold War" cover story, did you? Yes, on Christmas Eve the NORAD Santa Tracker system goes on line once again. And now you can even get updates to your mobile device, in case you feel like following Santa around in person.

And to all, a good night.

 

 

A Holiday Card from the International Space Station

Commander Scott Kelly of NASA and Flight Engineers Cady Coleman of NASA and Paolo Nespoli of the European Space Agency send all of us on Earth some Christmas and New Years wishes. Sweet, but they don't look very merry up there...

Interesting Data

A French satellite called DEMETER detected an increase in ultra-low-frequency radio emissions over Haiti during the months prior to the incredibly destructive earthquake there last January. For a long time there's been speculation about a connection between unusual electromagnetic effects and earthquakes -- unfortunately this speculation often slides right off the cliff into crackpottery. DEMETER was launched to keep tabs on ULF activity everywhere, so that scientists could then see if there is any correlation with quakes.

They've certainly found one in connection with the Haiti quake. The question is whether it's a strong correlation or a weak one -- in other words, do you get these effects only when a big quake is in the offing? Or does this kind of ULF activity happen when there's no geological activity? Because an earthquake detector which can give you a positive "something's going to happen in the next six weeks" is much more useful than one which says "maybe you're going to have an earthquake, maybe not."

Checklist

Neural Interface? Check.

Powered Exoskeleton? Check.

Jet Backpack? Check.

Armor? Check.

Mr. Stark, please call your office. You've suddenly ceased being a fictional character.

More Salt!

The always incisive Carl Zimmer weighs in on the arsenic-based life issue at Slate. Apparently a lot of scientists are not happy with the announced results. There are rumbles about flawed technique. It could get ugly. Start making popcorn.

Some Grains of Salt For a Halophile

The geekosphere has been buzzing over yesterday's announcement from NASA about the discovery of arsenic-based life. Specifically, a species of single-celled archaean living in hyper-salty, hyper-alkaline, arsenic-laced Mono Lake in California can actually use arsenic instead of phosphorus in its biological processes. If you Google it, there are already thousands of articles talking about how this dramatically expands the possibilities for life beyond Earth. In other words, we have an example of Life Not As We Know It.

Right?

Well . . . no.