Off kilter

I got an interesting email a few days ago, which I quote (with permission):

I keep running into references to places called "gravity hills" or "magnetic hills" where supposedly some force plays hell with your sense of what's up and what's down.  Trees and walls appear to lean, it's hard to stand up right, stuff like that.  But people say it's more than an illusion, because cars put in neutral at the bottom of an incline roll uphill, and balls placed on what appear to be level surfaces start to roll.

I can't come up with any way any of this could be real, but there are a lot of claims, so it's kind of the "can they all be false?" thing.  What do you know about this, and has it been explained scientifically?  Or is there really something paranormal going on?

I've heard about this phenomenon for years myself, and saying "there are a lot of claims" is a bit of an understatement.  In fact, Wikipedia has a list of reports of such "mystery hills" everywhere from Azerbaijan to Uruguay, and they all kind of have the same characteristics -- that the laws of gravity don't seem to apply, or that there's a strange "magnetic force" pulling stuff (including your proprioception) off kilter.

Let's clear one thing up from the get-go, though; if there is anything going on here, it has nothing to do with magnetism, because our sense of balance is controlled by the semicircular canals, fluid-filled tubes in your inner ear that use the movement of the liquid under the pull of gravity as a way of communicating to your brain "that direction is down."  Messing with this will make you dizzy and/or nauseated, which is why people get motion sickness; the apparent forces caused by spinning around on a carnival ride cause the fluid to slosh about, sending mixed signals to the brain and making some people violently ill.  (Why certain people seem to be more or less immune to motion sickness, and others get nauseated walking across the room, is unknown.)

So even if there was some mysterious "magnetism" at work here, it wouldn't affect your sense of balance unless your inner ears were made of cast iron.

But let's get down to specifics.  Here's how one of the most famous "mystery hills," the "Oregon Vortex," is described in John Godwin's book This Baffling World:

Situated thirty miles from Grant's Pass, the vortex -- which measures roughly 125 feet in diameter -- constitutes, according to its promoters, an electromagnetic phenomenon.

Within the "Oregon Vortex" there stands a hut, dubbed "The House of Mystery."  Its owner, John Lister, says, "Nowever in the area does the visitor stand upright.  Inevitably one assumes a posture that inclines toward magnetic north, beginning with a minimum of divergence from normal at the edge of the area, and increasing to an acute angle as "The House of Mystery" is entered.  So gradually is this latter stage reached that visitors seldom realize the phenomenon until the seemingly impossible posture of the guide or their friends brings a realization of their own tilting."

Suspended from the roof of "The House of Mystery" hangs a heavy steel ball, but that ball presumably doesn't hang straight down.  It would seem to lean inward, pulled toward the center of the hut by some weird gravitational shift.  It is claimed that a person who enters the hut will feel the odd pull quite distinctly; it is further alleged that the power which is exerted will force one to lean over at a ten-degree angle.  Viewers have alleged that a rubber ball, placed on the floor here, will roll uphill.

Another famous one is Magnetic Hill, near Moncton, New Brunswick, where a landmark (a light-colored telephone pole) appears to be the lowest point in the road when viewed from one direction, and the highest when viewed from the other.

[Image licensed under the Creative Commons Jim101, Magnetic Hill Moncton Front, CC BY-SA 3.0]

And of course, these stories are always accompanied with claims of other sorts of paranormal occurrences -- UFOs, ghosts, "skinwalkers," and the like -- and, in the United States at least, the inevitable stories about how the Indigenous people thought the place was cursed or haunted or a sacred burial ground or whatnot.

Now, to address the question -- is there anything to this?

Simple answer: no.

It turns out that humans are remarkably bad at piecing together visual cues with the information we get from our semicircular canals and coming up with a coherent picture of what the space around us is doing.  All it takes is a little messing about with the information we're receiving, and it befuddles us completely.

Take, for example, the following rather simple drawing:

[Image licensed under the Creative Commons Fibonacci, Zöllner illusion, CC BY-SA 3.0]

The diagonal lines running from the upper left to the lower right are all parallel, despite the fact that (1) they don't look it, and (2) even when you know what's going on and have proven it to yourself with a ruler, they still don't look it.  This is called the Zöllner Illusion, named after its discoverer, the astrophysicist Johann Karl Friederich Zöllner, and is a good indication that our ability to orient visually is not all it's cracked up to be.  (This is why the first thing pilots-in-training are taught is, "trust your instruments, not your senses.")

The "gravity hill" phenomenon is actually nothing more than an optical illusion as well, created by tilted surfaces that appear to be flat (or vice-versa) because the horizon is obscured, landmarks themselves are at an angle, or something is causing the eyes to misperceive the angle of inclination.  The whole thing was the subject of an extensive investigation that resulted in a paper in the journal Psychological Science, which concluded that the phenomenon is the result of a place's odd spatial layout combined with our faulty sensory-perceptive equipment.

So there's no alteration in the pull of gravity in these spots, or a mysterious electromagnetic anomaly, or a Great Disturbance in the Force, or whatever.  I'm not saying they're not fun; optical illusions are endlessly fascinating to me, but it's from the perspective of "wow, our brains are super easy to fool," not because of anything paranormal going on.

Anyhow, thanks to the reader who sent the question.  I always appreciate inquiries.  My opinion is that all of science starts from a desire to go from "We don't know" to "That's curious" to "Let's find out how it works."  

And even if in this case, the answer turns out to be less exciting than a rip in the space-time continuum, it's still pretty interesting.

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The forest primeval

A couple of days ago my friend and fellow writer Andrew Butters sent me a link about a new fossil discovery.  He hastened to point out that he'd thought of me because he knows I'm interested in paleontology, not because my name comes to mind when he thinks about antiquated relics.  There may have been a touch of local pride involved as well, because the discovery was made in his home province of New Brunswick, Canada.

There's no doubt that it was a remarkable find.  The fossil was unearthed in a quarry near the town of Norton, where there is a layer of 350-million-year-old sandstone deposited when Atlantic Canada was a tropical swamp.  This was near the beginning of the Carboniferous Period, a time when the Earth was significantly warmer and wetter than it is now.  The high temperatures and carbon dioxide levels boosted plant growth, causing the oxygen levels to rise to an estimated 35% (compared to today's 21%).  This had the effect of allowing animals that had previously been held back by their inefficient respiratory systems, especially arthropods, to become huge, leading to millipedes 2.5 meters long and dragonflies with 75-centimeter wingspans.

The plants, though, were also pretty different from what we've got around now; by far the most common ones today are flowering plants, which make their first unequivocal appearance in the fossil record about 130 million years ago, in the early Cretaceous Period.  So when the New Brunswick sandstone was being deposited, the first flowering plants were still 220 million years in the future.

The dominant plants back then were distantly related to today's ferns, horsetails, and club mosses, although as you'll see we don't have anything left that looks much like what you'd see in a typical Carboniferous forest.  But the fossil discovered in the Canadian quarry was bizarre even compared to a lot of the strange vegetation from that time -- and has drawn comparisons to something you might see in a book by Dr. Seuss.

"What it really does look like is one of those truffula trees from The Lorax," said Olivia King, of St. Mary's University in Halifax, who was part of the team that discovered the fossils.  The most remarkable thing about the fossil, though, is its amazing state of preservation.  It's thought to have been entombed in an upright position when a landslide caused part of the bank of a lake to collapse.  The entire tree was dragged down to the bottom of the lake and buried in sediment, where it's lain for 350 million years -- and now has been excavated carefully to reveal what it looked like when it was alive.  Dubbed Sanfordiacaulis densifolia, after quarry owner Laurie Sanford who has been instrumental in allowing the investigation to progress, it had a mop of spiky leaves topping a spindly trunk:

A reconstruction of Sanfordiacaulis densifolia [Image credit: artist Tim Stonesifer]

With the acceleration of plant growth during that time period, there was extreme competition to access light, leading to dramatic increases in plant height and canopy size.  Eventually, there were club mosses (genus Lepidodendron) fifty meters tall -- taller than the oaks and maples in an average hardwood forest.

A sampler of ancient trees, from Robert Gastaldo et al., Current Biology.  [Note: "Mississippian" and "Pennsylvanian" are two divisions of time usually lumped together as the Carboniferous Period.]

Of course, the good times -- at least if you were a weird club moss tree or a 2.5-meter-long millipede -- couldn't last forever.  Around 305 million years ago, the climate turned from hot and humid to cool and arid, probably because by that time the plants had locked up so much atmospheric carbon dioxide underground -- what would eventually become our coal deposits -- that the greenhouse effect decreased and the temperature fell.  In essence, the plants sowed the seeds of their own destruction, and in the Carboniferous rain forest collapse that followed, the enormous forests and many of the animals that depended upon them became extinct.

It also set the fuse for the largest mass extinction ever.  All that organic matter sequestered underground was tinder just waiting to burn, and when the Siberian Traps erupted 252 million years ago, the lava ripped through a huge chunk of the Carboniferous coal and peat, using up oxygen (dropping it to an estimated 12%) and dumping that excess carbon dioxide back into the atmosphere.  The temperature spiked, the oceans became anoxic, and something like 95% of life on Earth became extinct.

But at the point that the Sanfordiacaulis tree was growing in what would become New Brunswick, that cataclysmic event was still a hundred million years in the future.  Think about what a thrill it'd be to get to wander amongst those bizarre forests, so unlike anything we have today.

Even if it meant dodging enormous dragonflies.

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