This tumblr's for all the great men and women of science for whom we owe our current understanding of the natural world; their achievements, their failures, and even their quirks, we celebrate them all.
For Science. For Inquiry. For Humanity.
In the Coyote Buttes ravine in Arizona, huge waves of richly-coloured sandstone undulate across the landscape, looking as though they were painted by a giant hand. 190 million years ago in the Jurassic era, these sandstone waves (dubbed “The Wave”) were actually sand dunes migrating across the desert, but over the years they have calcified both horizontally and vertically, becoming compacted rocks. Their strange ridges and troughs were created by millions of years of wind and rain erosion, whose twists and turns reflect changes to the wind patterns in the Jurassic period. Erosion still affects the Wave today, mostly by wind that is now naturally channelled through it. This formation is a snapshot in geological time, a breathtaking exhibit of the effect of natural forces on their environment. It can only be reached on foot via a five kilometre hike, and since the sandstone is fairly soft, visitors are highly regulated—only twenty people are allowed to walk on the Wave each day. Walking across the weird, topsy-turvy landscape would be a surreal experience in itself, but if you need another reason to visit, the formation also boasts the fossil burrows of ancient arthropods like beetles—as well as the imprints of dinosaur tracks.
What do an orgasm, a multiplication problem and a photo of a dead body have in common? Each induces a slight, irrepressible expansion of the pupils in our eyes, giving careful observers a subtle but meaningful signal that thoughts and feelings are afoot.
For more than a century, scientists have known that our pupils respond to more than changes in light. They also betray mental and emotional commotion within. In fact, pupil dilation correlates with arousal so consistently that researchers use pupil size, or pupillometry, to investigate a wide range of psychological phenomena. And they do this without knowing exactly why our eyes behave this way. “Nobody really knows for sure what these changes do,” said Stuart Steinhauer, who directs the Biometrics Research Lab at the University of Pittsburgh School of Medicine.
While the visual cortex in the back of the brain assembles the images we see, a different, older part of our nervous system manages the continuous tuning of our pupil size, alongside other functions (like heart rate and perspiration) that operate mostly outside our conscious control. This autonomic nervous system dictates the movement of the iris, like the lens of a camera, to regulate the amount of light that enters the pupil.
The iris is made of two types of muscle: in a brightly lit environment, a ring of sphincter muscles that encircle and constrict the pupil down to as little as a couple of millimeters across; in the dark, a set of dilator muscles laid out like bicycle spokes, which can expand the pupil up to 8 millimeters - approximately the diameter of a chickpea.
Cognitive and emotional events can also dictate pupil constriction and expansion, though such events occur on a smaller scale than the light reflex, causing changes generally less than half a millimeter. But that’s enough. By recording subjects’ eyes with infrared cameras and controlling for other factors that might affect pupil size, like brightness, color, and distance, scientists can use pupil movements as a proxy for other processes, like mental strain.
Princeton psychologist Daniel Kahneman showed several decades ago that pupil size increases in proportion to the difficulty of the task at hand. Calculate 9 times 13, and you pupils will dilate slightly. Try 29 times 13, and they will widen further and remain dilated until you reach the answer or stop trying. Kahneman said he could divine when someone gave up on a multiplication problem simply by watching for pupil contraction during the experiment.
Subsequent research found that the pupils of intelligent people (as defined by their SAT scores) dilated less in response to cognitive tasks compared to those of less intelligent participants, possibly indicating a more efficient use of brainpower.
Scientists have since used pupillometry to assess everything from sleepiness to introversion, race bias, schizophrenia, sexual interest, moral judgment, autism, and depression. And while they haven’t been reading people’s thoughts per se, they’ve come pretty close.
“Pupil dilation can betray an individual’s decision before it is openly revealed,” concluded a 2010 study led by Wolfgang Einhäuser-Treyer, a neurophysicist at The Philipp University of Marburg in Germany. In the study, participants were told to press a button at any point during a 10 second interval, and their pupil size correlated with the timing of their decision. The dilation began about 1 second before they pressed the button and peaked 1 to 2 seconds after.
During the Cold War, Canadian officials tried to develop a device they called the “fruit machine” to detect homosexuality among government employees by measuring how their pupils responded to racy images of women and men. The machine, which never worked, was to aid the government’s purge of gay men and lesbians from the civil service and thereby purportedly reduce their vulnerability to Soviet blackmail.
A pupil test for sexual orientation remains as unlikely as it was in the 1960s. Researchers at Cornell University recently showed that sexual orientation correlated with pupil dilation to erotic videos of their preferred gender, but the trend was only apparent when averaged across subjects, and only for male subjects. While pupillometry shows promise as a noninvasive measure of sexual response, they concluded, “not every participant’s sexual orientation was correctly classified” and “an observable amount of variability in pupil dilation was unrelated to the participant’s sexual orientation.”
Pupillometry also became popular in the advertising industry during the 1970s as a way to test consumers’ responses to television commercials, said Jagdish Sheth, a marketing professor at Emory University. But the practice was eventually abandoned. “There was no scientific way to establish whether it measured interest or anxiety,” Sheth said.
The Most Bonkers Scientific Theories (Almost) Nobody Believes Anymore
Look, I’m not here to tell you what to think. But you need to be grateful for science – all of it. Even the crazy stuff. Even for folks who could have sworn it was possible to turn iron into gold, and even for that time when a brilliant astronomer thought that there could be life on the sun. Because great leaps in human understanding are always surrounded by backward steps and dead ends. It has to be OK to fail. Spectacularly.
In this gallery we present to you the silliest of the silly scientific theories, some of which you’ll no doubt recognize because for whatever reason people refuse to give up on them. So remember, there are no dumb theories, just dumb reasons to keep believing in long-discredited theories.
Lambs That Grow Like Weeds – Literally
The ancient Greeks were the first to have the crazy idea that a lamb could grow right out of the ground, with a stem attached to its navel. Pliny the Elder later mentioned it, and Europeans picked up the idea again in the 14th century.
This is the exceedingly strange legend of the Vegetable Lamb of Tartary.
Now, these folks were well aware of where lambs came from. They were baby sheep that came out of mommy sheep. Or a stork drops it off. Or whatever. But their story may have arisen out of the first Western accounts of cotton plants, which an ancient Greek by the name of Megasthenes found in India, referring to them as “trees on which wool grows.”
Then boom, people start thinking that lambs can grow out of the ground. Said Sir John Mandeville, a sort of 14th century travel writer, of India: “There grew there a wonderful tree which bore tiny lambs on the ends of its branches. These branches were so pliable that they bent down to allow the lambs to feed when they are hungry.”
The allure of the Vegetable Lamb of Tartary continued into the late 1700s, when it was still debated by botanists. Those being experts in plants.
A Brief Guide to Sutures.
If I planned to go into surgery, I would learn more of these. My current repertoire consists of the simple (over and inverted), subcuticular, horizontal mattress, vertical mattress, and lock-stitch sutures. This set of skills takes care of most problems.
The Most Intense Color of Any Living Thing on Earth
Also known as the marble berry, Pollia condensata is a wild plant that grows in the forests of several African countries. The berries are not edible, but they have an extremely rare property. They produce the most intense color of any living thing on Earth. Even after the berries have been picked from the plant, they stay the same shiny, vibrant, metallic blue color for many decades.
The vast majority of colors in the biological world are produced by pigments—compounds produced by a living organism that selectively absorb certain wavelengths of light, so that they appear to be the color of whichever wavelengths they reflect.
However, the marble berry’s skin has no pigment. The berries produce their vibrant blue color through nanoscale-sized cellulose strands that scatter light as they interact with one another. Thus the fruit’s color is even visible at the cellular level as pictured above.
Matthew Pillsbury - Museum Hours, 2004-2010
Click on each image for details.
See more from Museum Hours here.
This is a samara, the seed of maple tree. You may, like me, know it as a helicopter seed. They spin as they fall so they (hopefully) travel longer distances, thus growing saplings over a larger area.
Photo by brilliantbotany.