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A vertical map of Earth: How high or low can you go?
From La Rinconada in Peru to South Africa's deepest mines: the quest for gold drives people to the greatest heights and depths on Earth.
Most of our lives are spent relatively close to sea level. But Earth can be traveled in three dimensions—including up and down, from the rarefied heights of the tropopause to the crushing depths of the Mariana Trench. If you’ve flown long-distance, you’ve done the former. And that is fairly likely: at any given time, about 500,000 people are in the air. But unless you’re James Cameron, you’ve probably not done the latter. Here’s a cross-section of Earth: how high or low have you ever gone?
Cruising altitude of commercial airplanes (30,000–35,000 ft; 9.1-10.7 km)
The ideal cruising altitude for commercial airplanes, between 30,000 and 35,000 ft, is as high above the ground as most people are likely to get. To get any higher, you have to fly a military jet or become a full-fledged astronaut. So why do civilian planes fly this high?
First and foremost, to fly 'above the weather'. Up until the 1950s, commercial planes could not be pressurized and were thus limited to altitudes of 10,000 ft (3 km). This forced them to fly through heavy weather, with unpleasant consequences for the passengers. Even at 28,000 ft (8.5 km)—the ceiling for the Super-G Constellation, which came into service in the 1950s—this could not be totally avoided. But once beyond 30,000 ft, there's no more rain, snow, ice or turbulence.
Flying at this altitude brought extra advantages. For one, greater engine efficiency. Heat engines are most efficient where the air is coldest for their inlets, in this case in the tropopause—where the troposphere, the lowest layer of the atmosphere, changes into the stratosphere, which extends from around 6-11 miles (9-17 km) up to 30 miles (50 km) above the earth's surface.
Another advantage: lower air pressure at higher altitudes means less drag, allowing the plane to develop higher speeds with greater fuel efficiency than at lower altitudes. So why not fly even higher? Because the even thinner air would deprive the wings of their capacity to generate lift, while also reducing the engine's thrust.
One final plus of flying at great altitude: if you're flying in the right direction, the jet stream will give the plane an extra boost, further reducing fuel spend and flight time.
Mount Everest (29,035ft; 8,849.8 m)
The world’s tallest mountain was first conquered by Sir Edmund Hillary and Tenzing Norgay in 1953. Since then, about 4,000 other mountaineers have reached the summit. However, Everest has also claimed around 250 lives in the decades since the first ascent.
The Death Zone (26,000 ft; 7,900 m)
At this elevation, atmospheric pressure drops below 356 millibars and oxygen becomes too scarce to sustain human life. Oxygen-deprivation can lead to disorientation, loss of cognitive and bodily functions, and ultimately death. Extended stays above this elevation require supplementary oxygen. There are 14 mountain summits in the Death Zone, including Everest.
Ojos del Salado (22,595 ft; 6,886.9 m)
The second-highest peak in both the Western and Southern Hemispheres (1) and the highest active volcano in the world, Ojos del Salado last erupted around 700 AD. That seems pretty long ago to be classified as 'active', but there is some evidence for ash emission in 1993, as well as recent fumaroles (i.e. steam or gas vents).
Ojos del Salado is in the Andes, right on the Chilean-Argentinian border. In fact, the border runs between the mountain's two summits, which are virtually the same height. Its name is Spanish for 'Eyes of the Salty One', which refers to the salt deposits in the form of lagoons (or 'eyes') in its glaciers.
Its crater contains the highest lake in the world, at 20,960 ft (6,390 m). It was first climbed on 26 February 1937 by Polish mountaineers Jan Alfred Szczepański and Justyn Wojsznis.
La Rinconada (16,728 ft; 5,098.7 m)
The world's highest permanent settlement has few other attractions other than its altitude record. Except for the gold, of course.
Essentially, La Rinconada in Peru is a rough-and-tumble gold miners' camp the population of which has exploded in the first decade of this century as the price of gold has skyrocketed (+235% from 2001 to 2009).
Workers in the local goldmine work without pay for 30 days and then on the 31st day get to mine as much ore for themselves as they can.
Situated at the foot of a glacier called La Bella Durmiente ('The Sleeping Beauty'), La Rinconada is now home to around 50,000 people but lacks municipal services such as plumbing, heating or sanitation, or a hotel for visitors.
Despite its location close to the equator, La Rinconada's climate has more in common with that of western Greenland, with an average annual temperature of 1.2°C. La Rinconada is located 700 m higher than the next city with a comparable population, Cerro de Pasco—another Peruvian mining town.
Standard skydiving altitude (12,500 ft; 3,180 m)
The parachute was invented by André-Jacques Gamerin in 1797. He tested it by jumping out of a balloon 3,200 feet above Paris. Parachuting has since become a recreational activity, a competitive sport and a military technique for the deployment of personnel and supplies. The highest parachute jump ever was achieved on 24 October 2014 by Alan Eustace, who jumped from 135,890 feet (41,422 m).
To non-initiates, skydiving may seem scary. It's actually fairly safe. In 2015, the U.S. Parachute Association recorded just 21 fatalities out of a total of around 3.5 million jumps, which translates to a 0.006% chance of death while skydiving. According to the statistics of the National Safety Council, you're more likely to die from being struck by lightning or stung by a bee—or from driving to and from the drop zone.
Mount Fuji (12,389 ft; 3,776.2 m)
More than just the highest mountain of Japan, Mount Fuji is also one of the country’s three holy mountains (2) and an important national symbol. It's often been depicted in Japanese art and has figured on stamps and banknotes.
An active stratovolcano with a remarkably symmetrical cone, Mount Fuji can be seen from as far as Tokyo, 60 miles (100 km) to the northeast. It last erupted in 1707-'08, raining cinders and ash on the surrounding area. The eruption formed a second peak halfway down the southeastern side, named Mount Hōei.
The first ascent is ascribed to the semi-mythical monk Otsuno, in 663 AD. The first non-Japanese person to reach the summit was Sir Rutherford Alcock, in September 1868. Women were forbidden to climb the mountain until the late 1860s. Possibly the first one, and certainly the first non-Japanese woman to do so was Lady Fanny Parkes, the wife of the British ambassador, in 1869.
With more than 200,000 people climbing to the top each year, Mount Fuji is a major tourist attraction. The mountain is often climbed at night, in order to witness the sunrise at or near the summit. According to a Japanese saying, a wise person will climb Mount Fuji once in his life, but only a fool would climb it twice.
The Aokigahara Forest, at the northwest base of the mountain, has a grisly reputation. In olden days, poor families abandoned their very young and very old here. Today, the Forest is the world's second-most popular suicide location, after San Francisco's Golden Gate Bridge.
Ben Nevis (4,409 ft; 1,343.9 m)
The highest mountain in Scotland, and the British Isles. Its name, a translation from the original Gaelic, either means 'venomous mountain', or 'mountain with its head in the clouds'.
Its summit is the collapsed dome of an ancient volcano which blew up some 350 million years ago. Only in 1847 was Ben Nevis confirmed as the highest mountain in Britain and Ireland, over its rival Ben Macdhui.
The first attested climb to the top was on 17 August 1771 by James Robertson. In 1895, William Swan became the first person to run up the mountain, making it to the top and back to the old post office in Fort William in two hours and 41 minutes.
The Ben Nevis Race in its current form takes place every first Saturday of September. The current record times were both set in 1984, with Kenny Stuart running it in 1 hour, 25 minutes and 34 seconds, and Pauline Haworth in 1 hour 43 minutes and 25 seconds.
Currently, around 100,000 people each year climb the mountain. At the summit, they see the ruins of an observatory annex hotel that operated from 1883 to 1904. On a clear day, they can see all the way to Barra Head in Northern Ireland.
The next highest mountains are in western Norway, more than 400 miles (640 km) away. Two other peaks were named after Ben Nevis: a 3,025-ft (922-m) high mountain on the Norwegian archipelago of Svalbard, and a 1,604-ft (489-m) hill in Hong Kong, now known as Hung Fa Chai.
Burj Khalifa (2,717 ft, 828.1 m)
Since its completion in 2009, Burj Khalifa in Dubai has taken over from Taipei 101 in Taiwan as the world's tallest building, and from the Warsaw Radio Mast in Poland as the world's tallest man-made structure. Other records include building with most floors (211), longest distance traveled by elevators (1,654 ft; 504 m), and world's highest restaurant (122nd floor) and nightclub (114th floor).
The spire alone is 800 ft (244 m) tall, and widely considered 'vanity height', since it contains very little usable space. On its own, it's taller than all but 10 of the skyscrapers in Europe. At its top, the spire sways a total of 4.9 ft (1.5 m).
The tower has two outdoor observation decks: At The Top, on the 124th floor, at 1,483 ft (452 m); and SKY level on the 148th floor, at 1,821 ft (555 m). Both were the highest outdoor observation decks when they were inaugurated, but each was surpassed by a Chinese rival. Under ideal circumstances, the view from the top goes all the way to Iran, across the Gulf.
Shanghai Tower (2,073 ft; 631.8 m)
The Shanghai Centre Tower may just be the world's second-tallest building, but it does have the world's highest observation deck, on the 118th floor (and, at a top speed of 20.5 m/sec or 46 mph, the world's fastest elevators). It is flanked by two further super-tall buildings: the Jin Mao Tower and the Shanghai World Financial Centre. Such proximity of super-tall buildings is also a world first.
The Shard (1,004 ft; 306 m)
Opened in February 2013, The Shard—95% of which is owned by the State of Qatar—is the tallest building in the U.K. and the European Union. It is not, however, Europe's tallest building (as the map claims): three taller buildings overlook Moscow, the tallest one being the eastern tower of the Federation Towers, at least until the completion of the Lakhta Tower in St Petersburg, later this year.
Designed by Renzo Piano, The Shard has 95 storeys, 72 of which are habitable. There is a viewing gallery and an open-air observation deck on the 72nd floor, at 801 ft (244 m). In February 2011, a fox was discovered living on the then still partially completed 72nd floor. Nicknamed 'Romeo', it was rescued and released back in the wild, no doubt with stories to tell to its fellow foxes.
Bingham Canyon Mine (3,182 ft; 970 m)
A.k.a. Kennecott Copper Mine, this open-pit copper mine in Utah is the largest man-made excavation in the world and is visible from space. In operation since 1906, the mine has produced a pit over 0.6 miles (970 m) deep, 2.5 miles (4 km) wide, and covering 1,900 acres (770 ha).
As yet, it has produced 19 million tonnes of copper, more than any other mine in history. The value of the resources extracted (not just copper, but also molybdenum, silver and gold) at the Bingham Canyon Mine exceed those of the Comstock, Klondike and California Gold Rushes combined.
Depth of Grand Canyon (6,000 ft; 1,800 m)
Not that far from the Bingham Canyon Mine, the Grand Canyon isn’t actually below sea level either. “In fact, the bottom of the Grand Canyon is about 1,850 ft (560 m) above sea level", the graph's legend reads. "We've included it in the infographic to help highlight the sense of scale”.
Cuvier’s Beaked Whales (10,000 ft; 3,000 m)
Whales are mammals, so they can’t breathe underwater. Before they dive, they take a gulp of air at the surface and then go under—in the case of Cuvier’s beaked whales, up to 10,000 ft deep. That’s a lot farther down than sperm whales, which have been known to dive only as deep as 7,300 ft (2,225 m). To go that distance and come up for air again, Cuvier’s beaked whales have to hold their breath for a very long time. The longest recorded interval between surfacings is 2 hours and 17 minutes.
Wreck of the RMS Titanic (12,500 ft; 3,810 m)
The RMS Titanic is arguably the most famous shipwreck in history. The 'unsinkable' giant luxury cruiser sank on 15 April 1912 on its maiden voyage from Southampton in England to New York City, after striking an iceberg.
The wreck was not discovered until September 1985. It rests on the seabed of the North Atlantic Ocean, about 370 miles (600 km) southeast of Newfoundland, at a depth of about 12,500 feet, or 2.37 miles (3,800 m). The hull is broken in two, with the pieces lying about a third of a mile (600 m) apart, amid a field of smaller debris.
Several proposals to raise the wreck proved impractical, among other factors because of its great depth. Numerous dives have been organized since the wreck's discovery, some of which have salvaged items from the ship. This practice splits those concerned into two camps: 'conservationists', who feel it's defensible to rescue as many artifacts as possible from deep-sea oblivion; and 'protectionists', who want to maintain the integrity of the site as a memorial to the dead.
It has been estimated that the wreck could collapse as soon as 2025 and could be completely gone by 2037, due in large part to a species of rust-eating bacteria which was first discovered on the Titanic site itself. In 1995, director James Cameron made 12 dives to Titanic, resulting in footage used for his 1997 film Titanic.
Mponeng & TauTona Gold Mines (12,800ft; 3,900 m)
Mponeng and TauTona, both in South Africa’s Gauteng province, are the deepest gold mines in the world. Both are dangerous places to work: airconditioning is required to keep temperatures survivable, and each year, several miners die in accidents.
Mponeng extends about 2.5 miles (4 km) below the surface. Every day, 4,000 workers descend through triple-decked elevators which hold 120 people at the same time. It takes six minutes to descend the first 1.6 miles. The trip from the surface all the way to the bottom of the mine takes over an hour. Mponeng contains at least two gold reefs. Each day, over 5,400 metric tonnes of rock are extracted. To stay profitable, the mine needs to recover just 10 grams of gold per ton.
TauTona reached its current depth, approximately 2.4 miles (3.9 km) when it inaugurated a new shaft in 2008. The mine employs around 5,600 miners and has some 500 miles (800 km) of tunnels.
KTB Borehole (30,000 ft; 9,191 m)
KTB stands for Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland. In plain English: German Superdeep Hole. The project, located in Windischeschenbach in Bavaria, was conceived to study the effects of stress on layers of rock, abnormalities in the earth's crust, and how heat and stress were conducted through it.
The location was chosen because it's where the former continents of Laurasia and Gondwana merged into Pangaea. Drilling started in 1987 and continued to 1994 when depths of 30,000 ft (9,191 m) and temperatures of 265°C were reached. The derrick is one of the largest in the world and is a tourist attraction. Two smaller boreholes were kept open for further research.
Deepwater Horizon (35,055 ft; 10.7 km)
In 2009, the Deepwater Horizon drilled the deepest oil well in history, at a vertical length of 35,055 ft (10.7 km), in the Gulf of Mexico. On 20 April 2010, an explosion on the rig killed 11 crewmen and ignited a fireball visible from 40 miles (64 km) away. The resulting fire could not be extinguished and two days later Deepwater Horizon sank, leaving the well gushing at the seabed and causing the largest offshore oil spill in history.
Deepest Solo Submarine Dive (35,787 ft; 10.9 km)
James Cameron (yes, him again) in 2012 set the record for deepest solo dive in a submarine, diving in the Mariana Trench. The effort was made into a film titled Deepsea Challenge, after the name of his vessel.
Mariana Trench (36,201 ft; 11 km)
Located east of the Philippines and north of New Guinea in the western Pacific Ocean, the Mariana Trench, a half-moon-shaped scar in the earth's crust, is the deepest natural place in the world.
The Trench reaches its maximum depth in a small valley at its southern end known as the Challenger Deep. If Mount Everest were measured from the bottom of the trench, it would still be more than a mile (1.6 km) under water. Few animals can survive at these depths, where water pressure is more than 1,000 times the standard atmospheric pressure at sea level.
Curiously, the bottom of the Mariana Trench is not the closest bit of the earth's surface to its center. This is because the earth is not a perfect sphere: it is flatter at the poles, which means parts of the Arctic seabed are at least 13 km (8 mi) closer to the center of the earth than the seabed at Challenger Deep.
The Sakhalin-I Project (37,318 ft; 11.3 km)
Since 2003, a commercial consortium called Sakhalin-I has been exploring gas and oil deposits below and immediately offshore of Sakhalin Island in Russia’s Far East. The consortium has since conquered six of the 10 top spots in the ranking of longest drilling wells in the world.
In August 2012, the Z-44 Chayvo well reached a measured total length of 40,604 ft (12.3 km), making it the longest well in the world. That is a higher number than mentioned on this map, which has 37,318 ft down as the longest well.
This does not mean that Sakhalin now holds the record for the deepest artificial point on earth, as ‘longest’ boreholes don’t have to go straight down. The record for ‘deepest’ borehole is in Russian hands too, anyway.
The Kola Superdeep Borehole (40,230 ft; 12.3 km)
Located in Zapolyarny, about 100 miles northwest of Murmansk, the Kola Superdeep Borehole (in Russian: Kolskaya Sverkhglubokaya Skvazhina) was a Soviet scientific drilling project. From 1970, the Soviets attempted a ‘reverse moonshot’: to bore a hole in the earth’s crust deeper than anyone else had ever done.
The main target was set at 49,000 ft (15 km). By 1979, the Soviets had broken the record held by the Bertha Rogers hole in Washita, Oklahoma, at 31,440 ft (9.6 km). In 1989, borehole SG-3 reached a depth of 40,023 ft (12.3 km). The heat at that depth – around 356 °F (180°C) – made further progress impossible.
The 9-in (23-cm) wide hole has held the record of world’s deepest borehole ever since. In 1995, after the dissolution of the Soviet Union, the borehole was welded shut and the site closed off as an environmental hazard.
Strange Maps #893
Got a strange map? Let me know at firstname.lastname@example.org.
(1) behind the Aconcagua in Argentina, at 6,961 m (22,838 ft) the world's highest mountain outside Asia.
(2) the other two being Mount Tate and Mount Haku.
A man's skeleton, found facedown with his hands bound, was unearthed near an ancient ceremonial circle during a high speed rail excavation project.
- A skeleton representing a man who was tossed face down into a ditch nearly 2,500 years ago with his hands bound in front of his hips was dug up during an excavation outside of London.
- The discovery was made during a high speed rail project that has been a bonanza for archaeology, as the area is home to more than 60 ancient sites along the planned route.
- An ornate grave of a high status individual from the Roman period and an ancient ceremonial circle were also discovered during the excavations.
An ancient skeleton of a man dating back to the Iron Age was uncovered outside of London last month, and though archaeologists aren't certain what the cause of death was, clues point to a murder most foul.
A skeleton representing a man who was tossed face down into a ditch nearly 2,500 years ago with his hands bound in front of his hips was dug up during a high speed rail excavation.
The positioning of the remains have led archaeologists to suspect that the man may have been a victim of an ancient murder or execution. Though any bindings have since decomposed, his hands were positioned together and pinned under his pelvis. There was also no sign of a grave or coffin.
"He seems to have had his hands tied, and he was face-down in the bottom of the ditch," said archaeologist Rachel Wood, who led the excavation. "There are not many ways that you end up that way."
Currently, archaeologists are examining the skeleton to uncover more information about the circumstances of the man's death. Fragments of pottery found in the ditch may offer some clues as to exactly when the man died.
"If he was struck across the head with a heavy object, you could find a mark of that on the back of the skull," Wood said to Live Science. "If he was stabbed, you could find blade marks on the ribs. So we're hoping to find something like that, to tell us how he died."
Other discoveries at Wellwick Farm
The grim discovery was made at Wellwick Farm near Wendover. That is about 15 miles north-west of the outskirts of London, where a tunnel is going to be built as part of a HS2 high-speed rail project due to open between London and several northern cities sometime after 2028. The infrastructure project has been something of a bonanza for archaeology as the area is home to more than 60 ancient sites along the planned route that are now being excavated before construction begins.
The farm sits less than a mile away from the ancient highway Icknield Way that runs along the tops of the Chiltern Hills. The route (now mostly trails) has been used since prehistoric times. Evidence at Wellwick Farm indicates that from the Neolithic to the Medieval eras, humans have occupied the region for more than 4,000 years, making it a rich area for archaeological finds.
Wood and her colleagues found some evidence of an ancient village occupied from the late Bronze Age (more than 3,000 years ago) until the Roman Empire's invasion of southern England about 2,000 years ago. At the site were the remains of animal pens, pits for disposing food, and a roundhouse — a standard British dwelling during the Bronze Age constructed with a circular plan made of stone or wood topped with a conical thatched roof.
Ceremonial burial site
A high status burial in a lead-lined coffin dating back to Roman times.
Photo Credit: HS2
While these ancient people moved away from Wellwick Farm before the Romans invaded, a large portion of the area was still used for ritual burials for high-status members of society, Wood told Live Science. The ceremonial burial site included a circular ditch (about 60 feet across) at the center, and was a bit of a distance away from the ditch where the (suspected) murder victim was uncovered. Additionally, archaeologists found an ornately detailed grave near the sacred burial site that dates back to the Roman period, hundreds of years later when the original Bronze Age burial site would have been overgrown.
The newer grave from the Roman period encapsulated an adult skeleton contained in a lead-lined coffin. It's likely that the outer coffin had been made of wood that rotted away. Since it was clearly an ornate burial, the occupant of the grave was probably a person of high status who could afford such a lavish burial. However, according to Wood, no treasures or tokens had been discovered.
Sacred timber circle
An aerial view of the sacred circular monument.
Photo Credit: HS2
One of the most compelling archaeological discoveries at Wellwick Farm are the indications of a huge ceremonial circle once circumscribed by timber posts lying south of the Bronze Age burial site. Though the wooden posts have rotted away, signs of the post holes remain. It's thought to date from the Neolithic period to 5,000 years ago, according to Wood.
This circle would have had a diameter stretching 210 feet across and consisted of two rings of hundreds of posts. There would have been an entry gap to the south-west. Five posts in the very center of the circle aligned with that same gap, which, according to Wood, appeared to have been in the direction of the rising sun on the day of the midwinter solstice.
Similar Neolithic timber circles have been discovered around Great Britain, such as one near Stonehenge that is considered to date back to around the same time.
This spring, a U.S. and Chinese team announced that it had successfully grown, for the first time, embryos that included both human and monkey cells.
In the novel, technicians in charge of the hatcheries manipulate the nutrients they give the fetuses to make the newborns fit the desires of society. Two recent scientific developments suggest that Huxley's imagined world of functionally manufactured people is no longer far-fetched.
On March 17, 2021, an Israeli team announced that it had grown mouse embryos for 11 days – about half of the gestation period – in artificial wombs that were essentially bottles. Until this experiment, no one had grown a mammal embryo outside a womb this far into pregnancy. Then, on April 15, 2021, a U.S. and Chinese team announced that it had successfully grown, for the first time, embryos that included both human and monkey cells in plates to a stage where organs began to form.
As both a philosopher and a biologist I cannot help but ask how far researchers should take this work. While creating chimeras – the name for creatures that are a mix of organisms – might seem like the more ethically fraught of these two advances, ethicists think the medical benefits far outweigh the ethical risks. However, ectogenesis could have far-reaching impacts on individuals and society, and the prospect of babies grown in a lab has not been put under nearly the same scrutiny as chimeras.
Mouse embryos were grown in an artificial womb for 11 days, and organs had begun to develop.
Growing in an artificial womb
When in vitro fertilization first emerged in the late 1970s, the press called IVF embryos “test-tube babies," though they are nothing of the sort. These embryos are implanted into the uterus within a day or two after doctors fertilize an egg in a petri dish.
Before the Israeli experiment, researchers had not been able to grow mouse embryos outside the womb for more than four days – providing the embryos with enough oxygen had been too hard. The team spent seven years creating a system of slowly spinning glass bottles and controlled atmospheric pressure that simulates the placenta and provides oxygen.
This development is a major step toward ectogenesis, and scientists expect that it will be possible to extend mouse development further, possibly to full term outside the womb. This will likely require new techniques, but at this point it is a problem of scale – being able to accommodate a larger fetus. This appears to be a simpler challenge to overcome than figuring out something totally new like supporting organ formation.
The Israeli team plans to deploy its techniques on human embryos. Since mice and humans have similar developmental processes, it is likely that the team will succeed in growing human embryos in artificial wombs.
To do so, though, members of the team need permission from their ethics board.
CRISPR – a technology that can cut and paste genes – already allows scientists to manipulate an embryo's genes after fertilization. Once fetuses can be grown outside the womb, as in Huxley's world, researchers will also be able to modify their growing environments to further influence what physical and behavioral qualities these parentless babies exhibit. Science still has a way to go before fetus development and births outside of a uterus become a reality, but researchers are getting closer. The question now is how far humanity should go down this path.
Chimeras evoke images of mythological creatures of multiple species – like this 15th-century drawing of a griffin – but the medical reality is much more sober. (Martin Schongauer/WikimediaCommons)
Human–monkey hybrids might seem to be a much scarier prospect than babies born from artificial wombs. But in fact, the recent research is more a step toward an important medical development than an ethical minefield.
If scientists can grow human cells in monkeys or other animals, it should be possible to grow human organs too. This would solve the problem of organ shortages around the world for people needing transplants.
But keeping human cells alive in the embryos of other animals for any length of time has proved to be extremely difficult. In the human-monkey chimera experiment, a team of researchers implanted 25 human stem cells into embryos of crab-eating macaques – a type of monkey. The researchers then grew these embryos for 20 days in petri dishes.
After 15 days, the human stem cells had disappeared from most of the embryos. But at the end of the 20-day experiment, three embryos still contained human cells that had grown as part of the region of the embryo where they were embedded. For scientists, the challenge now is to figure out how to maintain human cells in chimeric embryos for longer.
Regulating these technologies
Some ethicists have begun to worry that researchers are rushing into a future of chimeras without adequate preparation. Their main concern is the ethical status of chimeras that contain human and nonhuman cells – especially if the human cells integrate into sensitive regions such as a monkey's brain. What rights would such creatures have?
However, there seems to be an emerging consensus that the potential medical benefits justify a step-by-step extension of this research. Many ethicists are urging public discussion of appropriate regulation to determine how close to viability these embryos should be grown. One proposed solution is to limit growth of these embryos to the first trimester of pregnancy. Given that researchers don't plan to grow these embryos beyond the stage when they can harvest rudimentary organs, I don't believe chimeras are ethically problematic compared with the true test–tube babies of Huxley's world.
Few ethicists have broached the problems posed by the ability to use ectogenesis to engineer human beings to fit societal desires. Researchers have yet to conduct experiments on human ectogenesis, and for now, scientists lack the techniques to bring the embryos to full term. However, without regulation, I believe researchers are likely to try these techniques on human embryos – just as the now-infamous He Jiankui used CRISPR to edit human babies without properly assessing safety and desirability. Technologically, it is a matter of time before mammal embryos can be brought to term outside the body.
While people may be uncomfortable with ectogenesis today, this discomfort could pass into familiarity as happened with IVF. But scientists and regulators would do well to reflect on the wisdom of permitting a process that could allow someone to engineer human beings without parents. As critics have warned in the context of CRISPR-based genetic enhancement, pressure to change future generations to meet societal desires will be unavoidable and dangerous, regardless of whether that pressure comes from an authoritative state or cultural expectations. In Huxley's imagination, hatcheries run by the state grew a large numbers of identical individuals as needed. That would be a very different world from today.
Sahotra Sarkar, Professor of Philosophy and Integrative Biology, The University of Texas at Austin College of Liberal Arts
Scientists should be cautious when expressing an opinion based on little more than speculation.
- In October 2017, a strange celestial object was detected, soon to be declared our first recognized interstellar visitor.
- The press exploded when a leading Harvard astronomer suggested the object to have been engineered by an alien civilization.
- This is an extraordinary conclusion that was based on a faulty line of scientific reasoning. Ruling out competing hypotheses doesn't make your hypothesis right.
Sometimes, when you are looking for something ordinary, you find the unexpected. This is definitely the case with the strange 'Oumuamua, which made international headlines as a potential interstellar visitor. Its true identity remained obscure for a while, as scientists proposed different explanations for its puzzling behavior. This is the usual scientific approach of testing hypotheses to make sense of a new discovery.
What captured the popular imagination was the claim that the object was no piece of rock or comet, but an alien artifact, designed by a superior intelligence.
Do you remember the black monolith tumbling through space in the classic Stanley Kubrick movie 2001: A Space Odyssey? The one that "inspired" our ape-like ancestors to develop technology and followed humanity and its development since then? What made this claim amazing is that it wasn't coming from the usual UFO enthusiasts but from a respected astrophysicist from Harvard University, Avi Loeb, and his collaborator Shmuel Bialy. Does their claim really hold water? Were we really visited by an alien artifact? How would we know?
A mystery at 200,000 miles per hour
Before we dive into the controversy, let's examine some history. 'Oumuamua was discovered accidentally by Canadian astronomer Robert Weryk while he was routinely reviewing images captured by the telescope Pan-STARRS1 (Panoramic Survey and Rapid Response System 1), situated atop the ten-thousand-foot Haleakala volcanic peak on the Hawaiian island of Maui. The telescope scans the skies in search of near-Earth objects, mostly asteroids and possibly comets that come close to Earth. The idea is to monitor the solar system to learn more about such objects and their orbits and, of course, to sound the alarm in case of a potential collision course with Earth. Contrary to the objects Weryk was used to seeing, mostly moving at about 40,000 miles per hour, this one was moving almost five times as fast — nearly 200,000 miles per hour, definitely an anomaly.
Intrigued, astronomers tracked the visitor while it was visible, concluding that it indeed must have come from outside our solar system, the first recognized interstellar visitor. Contrary to most known asteroids that move in elliptical orbits around the sun, 'Oumuamua had a bizarre path, mostly straight. Also, its brightness varied by a factor of ten as it tumbled across space, a very unusual property that could be caused either by an elongated cigar shape or by it being flat, like a CD, one side with a different reflectivity than the other. The object, 1I/2017 U1, became popularly known as 'Oumuamua, from the Hawaiian for "scout."
In their paper, Loeb and Bialy argue that the only way the object could be accelerated to the speeds observed was if it were extremely thin and very large, like a sail. They estimated that its thickness had to be between 0.3 to 0.9 millimeters, which is extremely thin. After confirming that such an object is robust enough to withstand the hardships of interstellar travel (e.g., collision with gas particles and dust grains, tensile stresses, rotation, and tidal forces), Loeb and Bialy conclude that it couldn't possibly be a solar system object like an asteroid or comet. Being thus of interstellar origin, the question is whether it is a natural or artificial object. This is where the paper ventures into interesting but far-fetched speculation.
I'm not saying it was aliens, but it was aliens
First, the authors consider that it might be garbage "floating in interstellar space as debris from advanced technological equipment," ejected from its own stellar system due to its non-functionality; essentially, alien space junk. Then, they suggest that a "more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," [italicized as in the original] concluding that a "survey for lightsails as technosignatures in the solar system is warranted, irrespective of whether 'Oumuamua is one of them."
You can shoot down as many hypotheses as you want to vindicate yours, but this doesn't prove yours is the right one.
I have known Avi Loeb for decades and consider him a serious and extremely talented astrophysicist. His 2018 paper includes a suggestive interpretation of strange data that obviously sparks the popular imagination. Theoretical physicists routinely suggest the existence of traversable wormholes, multiverses, and parallel quantum universes. Not surprisingly, Loeb was highly in demand by the press to fill in the details of his idea. A book followed, Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, and its description tells all: "There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization."
This is where most of the scientific establishment began to cringe. One thing is to discuss the properties of a strange natural phenomenon and rule out more prosaic hypotheses while suggesting a daring one. Another is to declare to the public that the only conceivable explanation is one that is also speculative. An outsider will conclude that a reliable scientist has confirmed not only the existence of extraterrestrial life but of intelligent and technologically sophisticated extraterrestrial life with an interest in our solar system. I wonder if Loeb considered the impact of his words and how they reflect on the scientific community as a whole.
This is why aliens won't talk to us
Earlier this year, in a live public lecture hosted by the Catholic University of Chile, Avi Loeb locked horns with Jill Tarter, the scientist that is perhaps most identifiable as someone who spent her career looking for signs of extraterrestrial intelligence. (Coincidentally, I was the speaker that followed Loeb the next week in the same seminar series and was cautioned — along with the other panelists — to behave myself to avoid another showdown. I smiled, knowing that my topic was pretty tame in comparison. I mean, how can the limits of human knowledge compare with alien surveillance?)
The Loeb-Tarter exchange was awful and, it being a public debate, was picked up by the press. Academics can be rough like anyone else. But the issue goes deeper.
What scientists say matters. When should a scientist make public declarations about a cutting-edge topic with absolute certainty? I'd say never. There is no clear-cut certainty in cutting-edge science. There are hypotheses that should be tested more until there is community consensus. Even then, consensus is not guaranteed proof. The history of science is full of examples where leading scientists were convinced of something, only to be proven wrong later.
The epistemological mistake Loeb committed was to make an assertion that publicly amounted to certainty by using a process of elimination of other competing hypotheses. You can shoot down as many hypotheses as you want to vindicate yours, but this doesn't prove yours is the right one. It only means that the other hypotheses are wrong. I do, however, agree with Loeb when he says that 'Oumuamua should be the trigger for an increase in funding for the search for technosignatures, a way of detecting intelligent extraterrestrial life.