from the world's big
Could Earth have a 'shadow' biosphere?
Some scientists think there may be a hidden, second form of life living right under our noses.
- All life on Earth shares some basic characteristics, such as being carbon-based; using DNA, RNA, and proteins to function; and so on.
- Many of these characteristics are simply the only ones that could work in Earth's environment, but there are also a surprising number of seemingly arbitrary features of life.
- Under the shadow biosphere theory, some scientists argue that alternative forms of life exist right here on Earth, undetected simply because we don't know to look for them.
In 2009, a NASA researcher isolated a peculiar bacteria from Mono Lake in California. Mono Lake is hypersaline and rich in arsenic, making it a difficult place for life to eke out an existence with the exception of some hard-scrabbling brine shrimp, the migratory birds that feed upon them, and some very interesting extremophile bacteria.
The researcher believed that this particular bacteria, dubbed GFAJ-1, was capable of an incredible trick. All life on Earth — and consequentially, all life that humans know of — uses phosphorus in its DNA. But when GFAJ-1 had no phosphorus, it seemed able to grow using just arsenic. The closest analogy would be to say that the researchers had just discovered alien life right on Earth.
There was a flurry of excitement and activity amongst the scientific community, but it was unfortunately short-lived; further research failed to replicate the experiment, and it appeared that GFAJ-1 was simply remarkably resistant to arsenic and had been surviving on trace amounts of phosphorus that had contaminated the culture.
This episode raises a question that bothers molecular biologists and astrobiologists alike; why is life the way it is? Why couldn't GFAJ-1 have used that arsenic molecule in place of the standard phosphorus molecule? There are plenty of hypothetical forms of life that simply couldn't exist under the conditions on Earth, such as silicon-based life rather than our carbon-based one, but there are also many, many variations on Earth's carbon-based life that should do fine.
These questions lead to another: What if there are indeed other forms of microbial life on Earth, unnoticed but existing in parallel with our own? This hypothetical scenario is referred to as the shadow biosphere.
Mysterious co-inhabitants of Earth
Mono Lake and GFAJ-1 (inset).
If Earth hosted not one, but two fundamentally different forms of life, it would substantially increase the odds of alien life existing out in the universe. If a shadow biosphere existed, then it would stand to reason that when a planet exists under the right conditions, life doesn't just have a shot at emerging, it's practically guaranteed.
But then again, this idea also seems extremely far-fetched. If a second form of life existed in parallel alongside our own, one would expect that we would have detected it by now. To that point, proponents argue that our techniques for detecting life are based on our current understanding of it. Hypothetical, alternate microbial life forms could go undetected.
It is important to note that the majority of biologists do not endorse the idea of a shadow biosphere. There is little evidence to suggest that such a biosphere exists, and it is extremely difficult to prove a negative, so we are left with assuming that ours is the only format that life takes. Still, contemplating the shadow biosphere is a useful exercise, as it may help us understand alien life. Not to mention that the shadow biosphere may in fact be real.
What would the shadow biosphere look like?
All life relies on DNA, RNA, and proteins to function. DNA and RNA are composed of 5 nucleobases in total, and proteins are composed of 20 amino acids. The problem is that these 5 nucleobases and 20 amino acids seem arbitrary — there are plenty of other nucleobases and hundreds of naturally occurring and abundant amino acids. Meteorites have even landed on Earth loaded with these apparently extraneous amino acids and nucleobases. It's plausible that alternate forms of life could use different combinations of these building blocks.
Another possible candidate for the shadow biosphere would be RNA-based life. Both DNA and RNA carry genetic information, and life on Earth uses both to function. Unlike DNA, RNA only has a single strand, uses the nucleobase uracil rather than thymine, and directly codes for amino acids.
Because RNA is structurally simpler than DNA, some scientists argue that predominantly RNA-based life evolved first on Earth, often referred to as the "RNA World." Under a shadow biosphere, such life would have persisted, branching off from what would eventually become DNA-based life.
There could also be organisms with the opposite chirality to ours. Perhaps one of the most arbitrary characteristics that life on Earth exhibits is its chirality, or handedness. In molecular biology, the shape of a molecule plays a large part in its function, but some shapes are simply mirror images of the other, like our left hand is a mirror image of our right.
These molecules are functionally the same, they just need the right kind of molecular machinery to work. Life on Earth has somehow decided that left-handed amino acids make up proteins and right-handed sugars make up our DNA and RNA, but there's no reason why this couldn't be flipped. We may be exposed to molecular life with the opposite chirality to ours and not even know it; none of our cells could interact with a molecule using the "wrong" hand to ours.
Unfortunately, we will likely only be able to shut the book on the shadow biosphere if we find life that deviates from the formula that seems to work so well on Earth. Proving the absence of all other varieties of life on Earth is an impossible task, so we will likely be left to speculate. If, however, we do discover evidence of a shadow biosphere in some of Earth's stranger nooks and crannies, we will have to look at life in the universe from an entirely new point of view.
Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.
- Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
- As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
- The film is perfectly timed for a world sheltering at home during a pandemic.
In more than a dozen countries as far apart as Portugal and Russia, 'Smith' is the most popular occupational surname
- 'Smith' is not just the most common surname in many English-speaking countries
- In local translations, it's also the most common occupational surname in a large part of Europe
- Ironically, Smiths are so ubiquitous today because smiths were so special a few centuries ago
Meet the Smiths, Millers, Priests and Imams - the most popular occupational surnames across Europe.
Image: Marcin Ciura<p>Although very few people are smiths by profession these days, there are millions of Smiths by surname the world over. It's the most popular surname in Britain, Australia, New Zealand and the United States, as well as the second most popular surname in Canada and the fifth most popular one in Ireland. And they're a thriving bunch, at least in the U.S.: the 2010 Census (1) counted 2,442,977 Americans called Smith, 2.8% more than in 2000.</p><p>Curiously, 'Smith' also is one of the most popular surnames across most of Europe –translated in the various local vernaculars, of course. This map shows the most common occupational surnames in each country. By colour-coding the professions, this map shows a remarkable pro-smith consistency across Europe – as well as some curious regional exceptions.</p>
‘Smith’ popular throughout Europe<p>'Smith', in all its variations, is the most popular occupational surname throughout Europe. Not just in the UK, but also in:</p> <ul><li>Belgium (<em>Desmet</em>) and Luxembourg, (<em>Schmitt</em>);</li> <li>France (<em>Lefebvre</em>), Italy (<em>Ferrari</em>) and Portugal (<em>Ferreira</em>);</li> <li>Slovenia (<em>Kovačič</em>), Croatia (<em>Kovačevič</em>), Hungary (<em>Kovács</em>), Slovakia (<em>Kováč</em>), Poland (<em>Kowalski</em>), Lithuania (<em>Kavaliauskas</em>), Latvia (<em>Kalējs</em>) and Belarus (<em>Kavalyov</em>);</li> <li>Estonia (<em>Sepp</em>); and</li> <li>Russia (<em>Kuznetsov</em>).</li></ul>
‘Miller’ on top in many Germanic-language countries<p>'Miller' is the most popular occupational surname in many Germanic-language countries, but also in Spain and Ukraine (perhaps because the grain in both countries is mainly in the plain):</p> <ul><li>There's <em>Müller</em> (in Germany and Switzerland), <em>M</em><em>ø</em><em>ller</em> (in Denmark and Norway) and <em>Möller</em> (Sweden);</li> <li><em>Molina</em> (in Spain – the map also shows the most popular surname in Catalonia/Catalan: <em>Ferrer</em>, i.e. 'Smith'); and</li> <li><em>Melnik</em> (in Ukraine).</li></ul>
Clergy surnames rule in the Balkans<p>Catholic clergy must remain celibate, so 'Priest' as a surname is rare to non-existent throughout Europe. Except in the Balkans, where Catholicism is largely absent. Here, the Orthodox and Islamic clergies have passed on the title from father to son, eventually as a surname, to popular effect. Orthodox clergy are addressed as <em>papa</em> or <em>pope</em> (which means 'father' – so the surname rather redundantly translates to 'father's son'). Islamic teachers or imams are known by the Turkish/Persian term <em>hodzha</em>. An overview:</p> <ul><li><em>Popov</em> (in Bulgaria), <em>Popovic</em> (in both Serbia and Montenegro), <em>Popovski</em> (in Macedonia);</li> <li><em>Popa</em> (in Romania); </li> <li><em>Papadopoulos</em> (in Greece); and</li> <li><em>Hodžić</em> (in Bosnia-Herzegovina), <em>Hoxha</em> (in both Kosovo and Albania).</li></ul>
Landowners and other professions<p>Austria and the Czech Republic have different national languages but are neighbours and share a lot of history. Could that explain why they have a similar most popular occupational surname, for 'landowner'?</p> <ul><li><em>Huber</em> (in Austria) and</li> <li><em>Dvořák</em> (in the Czech Republic).</li></ul> <p>Just four professions, that wraps up all but five countries on this map. Those five each have their very own most popular occupational surname:</p> <ul><li><em>Bakker</em> (in the Netherlands): 'Baker'</li> <li><em>Kinnunen</em> (in Finland): 'Skinner'</li> <li><em>Ceban</em> (in Moldova): 'Shepherd'</li> <li><em>Avci</em> (in Turkey): 'Hunter'</li> <li><em>Murphy</em> (in Ireland): 'Sea Warrior' </li></ul>
Even more Smiths<p>Judging from the popularity of these surnames, your generic European village of a few centuries ago really couldn't do without a smithy. It was a much more essential craft even than that of the miller (or the baker, who put the miller's flour to good use) – except in the Balkans, where spiritual sustenance apparently sated a greater need. On the outskirts of <em>Anytown, Europe</em> live the shepherd and the hunter, the skinner and the pirate.<br></p><p>A bit too simplistic? Perhaps not simplistic enough. This map could have been dominated by even more Smiths. As the original poster explains, he always picked the most frequent version of an occupational surname, even if multiple variants point to a more popular alternative. </p><p>In the Netherlands, for instance, people with the surnames <em>Smit, Smits, Smid, de Smit, Smet </em>and <em>Smith</em> collectively outnumber those with the surnames <em>Bakker, Bekker, de Bakker</em> and <em>Backer</em>. So, the Netherlands could be considered another win for 'Smith' – except that the variant <em>Bakker</em> is more frequent than any other single variant.</p><p>Same story in Germany: added up, there are more people named <em>Schmidt, Schmitt, Schmitz </em>and <em>Schmid</em> than <em>Müller</em>. Ditto for Spain: <em>Herrero, Herrera </em>and <em>Ferrer</em> together outnumber <em>Molina</em>. Also in Finland, where <em>Seppä</em>, <em>Seppälä</em> and <em>Seppänen</em> together have a higher count than <em>Kinnunen</em>. </p>
Smiths in other cultures<p>'Smith' was a crucial occupation in other cultures too, judging from the familiar ring it has in these languages:<br></p><ul><li><em></em><em>Demirci</em> (Turkish)</li><li><em>Hadad</em> (Syriac, Aramaic, Arabic)</li><li><em>Nalbani</em> (Albanian)</li><li><em>McGowan</em> (Gaelic)</li><li><em>Faber</em> (Latin)<span></span></li></ul>
Other most popular surnames<p>Take note, though: 'Smith' may be the most popular surname in in the Anglosphere, this map does not mean to show that its variants in French, Russian and other languages also are the most popular surnames in the countries marked grey. They are merely the most popular <em>occupational</em> surnames.<br></p><p>As this sample of most common ones for each country shows, surnames can refer to a host of other things. Personal qualities or physical attributes, for example:</p> <ul><li>Russia: <em>Smirnov</em> ('the quiet one')</li> <li>Turkey: <em>Yilmaz</em> ('unflinching')</li> <li>Hungary: <em>Nagy</em> ('big')</li> <li>Italy: <em>Rossi/Russo</em> ('red', in northern and southern Italy, respectively)</li></ul> <p>Another option: the origin of the name-bearer (be it a place or a person):</p> <ul><li>Sweden: <em>Andersson</em> ('son of Anders')</li> <li>Slovakia: <em>Horvath</em> ('Croat')</li> <li>Kosovo: <em>Krasniqi</em> (refers to the Krasniq tribe and their mountainous home region)</li> <li>Portugal: <em>Silva</em> ('woodland')</li> <li>Latvia: <em>Bērziņš</em> ('little birch tree')</li> <li>Estonia: <em>Tamm</em> ('oak')</li></ul> <p>But sometimes, even for the most popular ones, the exact origin of the surname is lost in time:</p> <ul><li>Spain: <em>Garcia</em> (originally Basque, possibly meaning 'young', 'bear' or 'young bear')</li> <li>Finland: <em>Korhonen</em> ('hard of hearing' or 'dim-witted'; 'village elder'; 'proud'; 'upright'). </li></ul>
Smith popularity theory<p>So why exactly is Smith – and not Miller, for example – the most popular surname in many English-speaking countries? The theory propounded by historian C.M. Matthews in <em>History Today</em> (July 1967) probably also holds for the other-language variants so popular throughout Europe:<br></p><blockquote>"The reason for (the) multiplicity (of the surname 'Smith') is not so much that metal-workers were numerous as that they were important and widespread. On the skill of the smith, both rich and poor depended for the most essential things of life, the tools of husbandry and the weapons of hunting and war. Every community in the land must have one, every castle, every manor; and so distinctive was his trade that he would seldom need another name".<em></em></blockquote><p>That does not mean all people with the surname have a forefather who forged iron into weapons and farm tools. Especially in North America, 'Smith' was adopted by many people precisely because it was already common – as a secret identity or to blend in, for example by natives, slaves and immigrants.</p>
A recent analysis of a 76-million-year-old Centrosaurus apertus fibula confirmed that dinosaurs suffered from cancer, too.
- The fibula was originally discovered in 1989, though at the time scientists believed the damaged bone had been fractured.
- After reanalyzing the bone, and comparing it with fibulas from a human and another dinosaur, a team of scientists confirmed that the dinosaur suffered from the bone cancer osteosarcoma.
- The study shows how modern techniques can help scientists learn about the ancient origins of diseases.
Centrosaurus apertus fibula
Royal Ontario Museum<p>In the recent study, the team used a combination of techniques to analyze the fibula, including taking CT scans, casting the bone and studying thin slices of it under a microscope. The analysis suggested that the dinosaur likely suffered from osteosarcoma, a type of bone cancer that affects modern humans, typically young adults.</p><p>For further evidence, the team compared the damaged fibula to a healthy fibula from a dinosaur of the same species, and also to a fibula that belonged to a 19-year-old human who suffered from osteosarcoma. Both comparisons supported the osteosarcoma diagnosis.</p>
Evans et al.<p style="margin-left: 20px;">"The shin bone shows aggressive cancer at an advanced stage," Evans said in a <a href="https://www.rom.on.ca/en/about-us/newsroom/press-releases/rare-malignant-cancer-diagnosed-in-a-dinosaur" target="_blank">press release</a>. "The cancer would have had crippling effects on the individual and made it very vulnerable to the formidable tyrannosaur predators of the time."</p><p style="margin-left: 20px;">"The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it normally would have with such a devastating disease."</p><p>The fossilized fibula was originally unearthed in a bonebed alongside the remains of dozens of other <em>Centrosaurus </em><em>apertus</em>, suggesting the dinosaur didn't die from cancer, but from a flood that swept it away with its herd.</p>
Dinosaur fibula; the tumor mass is depicted in yellow.
Royal Ontario Museum/McMaster University<p>The new study highlights how modern techniques can help scientists learn more about the evolutionary origins of modern diseases, like cancer. It also shows that dinosaurs suffered through some of the same terrestrial afflictions humans face today.</p><p style="margin-left: 20px;">"Dinosaurs can seem like mythical creatures, but they were living, breathing animals that suffered through horrible injuries and diseases," Evans said, "and this discovery certainly makes them more real and helps bring them to life in that respect."</p>
Join the lauded author of Range in conversation with best-selling author and poker pro Maria Konnikova!
UPDATE: Unfortunately, Malcolm Gladwell was not able to make the live stream due to scheduling issues. Fortunately, David Epstein was able to jump in at a moment's notice. We hope you enjoy this great yet unexpected episode of Big Think Live. Our thanks to David and Maria for helping us deliver a show, it is much appreciated.