Holey Spaghettification! Surprising Holes in Science
Spaghettification sounds more like a culinary mishap than an astronomical phenomenon. Otherwise known as a tidal disruption event, the term describes how black holes rip apart objects that venture too close. Thanks to new observations of an ill-fated star’s spectacular demise and the recent announcement of the Nobel prize in physics, black holes are trending on a cosmological scale.
Although these cosmic curiosities get all the glory, there are plenty of other noteworthy holes in science. Here are a few of the most interesting hollows, voids, pits, and cavities the natural world has to offer.
Rabbit Holes
If Lewis Carroll had lived in the United States instead of England, Alice may have followed a woodchuck to Wonderland instead of a rabbit. Unlike their European counterparts, most North American rabbits aren’t the burrowing type.
There are roughly 15 species of rabbits and hares in North America, but only two – the pygmy rabbit in the western U.S. and Mexico’s volcano rabbit – dig their own burrows. Cottontails are the most ubiquitous of the New World rabbits, and chances are the bunnies you see in your yard belong to this group. There are about eight different species of cottontails in the U.S., including the Eastern cottontail, desert cottontail, swamp rabbit, marsh rabbit, and brush rabbit.
Cottontails don’t dig burrows. Instead, they hide in brush or tall grass, where they scratch out shallow nests for resting or giving birth. However, these subterranean squatters sometimes occupy the abandoned burrows of ground squirrels, prairie dogs, and woodchucks.
A woodchuck wearing a waistcoat doesn’t have the same charm as a white rabbit. Fortunately for literature fans, European rabbits, like those in England, are exceptional excavators, creating extensive networks of burrows called warrens. These seemingly haphazard arrays of interconnecting tunnels include living quarters, nesting areas, and a multitude of emergency entrances and exits.
The size of warrens varies greatly, with some extending more than 3 yards (1 meter) deep and 50 yards (45 meters) long. A small warren may be home to a single pair of rabbits, while larger ones may house several dozen individuals. The bigger warrens resemble an underground village, with central areas that all rabbits may access and separate “houses” or chambers that are exclusive to smaller groups or families. In these hierarchal societies, a dominant male buck rules the rabbit roost.
European rabbits are not native to England, and historians believe they were introduced by the Normans sometime in the 11th century. Luckily, the rabbits and their wondrous warrens were well-established by the time Lewis Carroll crafted his legendary lagomorph.
Black Holes
Despite their name, black holes aren’t really holes at all. Instead, they are regions of space so dense that nothing, including light, can escape. They form when a huge amount of matter is squeezed into a tiny space, creating a super strong gravitational field.
Black holes come in three sizes – extra small, medium, and extra-extra-large. Scientists believe the smallest black holes are the size of a single atom but contain the mass of a large mountain. The medium-sized black holes, called stellar black holes, are formed by imploding stars, and they are about twenty times more massive than the Sun. Supermassive (or XXL) black holes are more massive than one billion Suns, and every large galaxy, including our own Milky Way, has a supermassive black hole at its center.
Since black holes don’t emit light, they are invisible – which makes it challenging for astronomers to confirm their existence. However, in 2019, scientists captured the first photograph of the silhouette of a supermassive black hole by simultaneously aiming a planet-wide network of radio telescopes at the super-heated glowing gas and dust encircling it. Scientists estimate the black hole, which is at the center of the Messier 87 galaxy, is 6.5 billion times the mass of the Sun and 55 million light years away.
Black holes are surrounded by an imperceptible sphere known as the event horizon, or more ominously, the point of no return. Beyond this point, the gravitational pull is so strong that an object would have to travel faster than the speed of light to escape its grip. Since this is impossible, any star, planet or unlucky space traveler that crosses this precipice meets a regrettable fate.
So, what exactly happens when matter passes the event horizon? Imagine holding a lump of Silly Putty in one hand and using the fingers on your other hand to stretch out the putty as far as possible. As it stretches, it gets longer and thinner. Similarly, if you fell feet first into a stellar black hole, the gravitational pull on your feet would be millions of times stronger than the pull on your head, stretching you out like a strand of pasta. Scientists refer to this phenomenon as spaghettification, or the noodle effect.
If the thought of being spaghettified hasn’t ruined your appetite for interstellar travel, NASA’s tongue-in-cheek warning about the perils of black holes might curb your cosmological cravings.
Sinkholes
With names like Golly Hole, Devil’s Den, Cedar Sink, Marvel Cave and Green Banana Hole, a list of notable sinkholes sounds a lot like a mini-golf course. Despite their playful monikers, these perilous pits often spell disaster for unsuspecting homeowners and motorists.
Sinkholes form when the bedrock beneath the soil erodes due to chemical weathering. As rainwater moves down through the soil, the underlying rocks begin to dissolve, creating cavities. Over time, these cavities can become large caverns. When the underground holes become too big to support the overlying land, it collapses – sometimes catastrophically.
Sinkholes occur most frequently in what geologists call karst terrain. These are regions where rainfall is plentiful and the bedrock consists of limestone, gypsum, dolomite, or other carbonate-rich rocks that dissolve easily. The U.S. states most susceptible to sinkholes include Florida, Texas, Tennessee, Pennsylvania, Alabama, Missouri, and Kentucky. Southern Italy, Mexico’s Yucatan Peninsula, and areas of China and Guatemala are also vulnerable.
With a depth ranging between 1,677 and 2,172 feet (511 to 662 meters) and a length of 2,054 feet (626 meters), China’s Xiaozhai Tiankengmay be the largest sinkhole in the world. This tiankeng, or heavenly pit, formed when an underground river carved out a cavern that eventually collapsed.
The Golly Hole in Alabama is one of the largest modern sinkholes in the United States. Formed in 1972, the sinkhole is about 325 feet (99 meters) long, 300 feet (91 meters) wide, and 120 feet (37 meters) deep. It reportedly occurred during a period of drought when the water table was considerably lower than normal. Without the fluid pressure of the groundwater to support the overlying soil, the land collapsed with a deafening roar. A pair of hunters discovered the hole two days later, and their awestruck reaction inspired the landmark’s name.
You probably wouldn’t expect to see an exhibit about sinkholes at an automotive museum, but that’s what you’ll find when you visit the National Corvette Museum in Kentucky. In 2014, the roof of a previously unknown cave beneath the museum collapsed, creating a massive sinkhole that swallowed up eight cars. Visitation to the museum skyrocketed following the disaster, as people flocked to the site to witness the devastation firsthand. In 2016, the museum opened an exhibit that explains how the karst formation facilitated the collapse and describes the efforts to repair the damage.
Blowholes
Suppose you could only breathe through your nose. This might be fine while chilling on the couch, but you would have a tough time jogging or even walking up a long flight of stairs without struggling. Unlike humans, cetaceans (whales and dolphins) breathe exclusively through their nostrils, or blowholes. Fortunately, their huge lungs are very efficient at exchanging oxygen, and some species can go more than an hour between breaths.
Baleen whales, such humpbacks and blue whales, have a pair of blowholes, much like the nostrils of other mammals. However, toothed whales, which includes dolphins and porpoises, have a single external blowhole connected to two internal nasal passages. Scientists suspect these structural differences are related to body size and oxygen needs. With the exception of the sperm whale, toothed cetaceans are smaller and make shorter dives than their baleen brethren, meaning they need to take in less oxygen each time they surface.
With bodies bigger than buses, whales need big nostrils to fill their lungs. The blue whale’s blowhole measures about 20 inches (51 cm) across. Compare that to a Dominos extra-large pizza, which is a mere 16 inches (41 cm) in diameter. A sphincter muscle controls the opening and closing of the blowhole. The muscle contracts to open the blowhole and permit air exchange when whales surface, and it relaxes to seal the blowhole and prevent water from entering when diving.
Despite what Disney would have you believe, Marlin and Dory could not have escaped the mouth of whale by being blasted out its blowhole. Unlike humans, whales have a pharyngeal plug that blocks the connection between their mouths and their nostrils. The air from their blowhole travels directly to their lungs via the trachea, while their mouth connects only to the esophagus and digestive tract. With no passageway between their mouth and lungs, whales can eat underwater without drowning.
The spout you sometimes see when whales come to the surface is called blow, and it can travel at alarming speeds – about 62 mph (100 km/h) for dolphins and up to 300 mph (480 km/h) for blue whales. In addition to exhaled air, blow contains mucus and epithelial cells from the lining of the lungs and nostrils. Scientists study this whale “snot” to monitor the health and well-being of these massive mammals.
Researchers fly a modified drone called SnotBot through the blow of a whale and collect exhaled snot on petri dishes. The blow samples contain DNA, hormones, microbiomes, and other indicators of the animal’s health. Equipped with this information, scientists can tell if whales are pregnant or stressed and track the spread of diseases. For these marine biologists, the phrase “there she blows” is a slogan for saving whales rather than hunting them.
