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Medieval horses buried in London had far-flung origins

New Scientist Feed - Fri, 03/22/2024 - 11:00am
Isotopic analysis of horse teeth from a medieval burial site suggest that the animals were imported to England from Scandinavia or the Alps, perhaps for use in battle or jousting
Categories: Science

Dogs really do understand that words stand for objects

New Scientist Feed - Fri, 03/22/2024 - 8:00am
Pet dogs have different patterns of brain activity when they are shown an object that doesn’t match the word they hear, suggesting they have a mental representation of what words mean
Categories: Science

Melanie Phillips on America’s war with Israel

Why Evolution is True Feed - Fri, 03/22/2024 - 7:45am

If you’re an American who supports Israel in its war against Hamas, you’re subject not only to a barrage of bizarre and untenable claims, but also must ride an emotional roller coaster controlled by Biden and Blinken. These B brothers seem determined to control Israel’s behavior in the war, going back and forth in what they dictate to the Jewish country.  We are told that the war must stop because too many Gazan civilians have been killed in proportion to dead terrorists, yet the ratio is by all rational accounts roughly 1.5:1—one of the lowest ratios of civilians/combatants killed in modern warfare.  (And of course the media always use the dubious figures presented by Hamas as if they were accurate!)

We see Blinken telling Israel that they must hold an election now to get rid of Netanyahu—a reprehensible interference in democratic politics, and during wartime!   (I’m not a big fan of Netanyahu, and am sure he’ll be deposed in the next election, but now he’s part of a three-person war cabinet that, with help from the Israeli military is directing the fighting. And two of those members are, unlike Netanyahu, from the Israeli Left).

We see the world, including America, issuing dire warnings that Israel must not invade Rafah, despite the fact that that is where the Hamas leadership and a large proportion of its fighters have holed up, and despite Israel having plans to evacuate civilians. Without going into Rafah, Hamas will not be destroyed, and of course will not voluntarily give up power. Keeping Israel out of Rafah is, as all pro-Palestinians realize, a recipe for keeping Hamas in power.

We see the American administration broaching the idea that the Palestinian Authority should rule postwar Gaza, despite the fact that Gazans despise the PA. And the PA is a corrupt, terror-promoting organization that pays Palestinians who kill Jews in its odious “pay for slay” program (or, as Wikipedia calls it, the “Martyrs’ Fund“). What kind of moron would suggest that the PA take over running Gaza? And if any remnants of Hamas remain, they won’t be allowed to.

And now the ultimate insult: the U.S. will propose today a UN Security Council resolution that will call for a ceasefire and release of hostages.  The details are hazy, but the resolution is aimed not at Hamas but at Israel, for, given the details, it could lead to the resurrection of Hamas and its attendant terror attacks.  Realize that since October 7 there has been not one UN resolution, be it in the General Assembly or the more important Security Council, that has condemned what Hamas has done and told it to lay down its arms, release the hostages, and surrender.

One gets the impression that for a very brief time after October 7 the West was on the side of Israel, but that didn’t last long.  Now, it seems, the West, including the U.S., wants Hamas to win—or at least Israel to vanish. Why? Well, of course Biden is sweating bullets over winning a close election in November, and he needs the votes of Muslims and young people who don’t favor Israel.  Further, the casualty ratio is too high for most people, who don’t seem to realize that it’s an extraordinarily low ratio of civilians killed to terrorists killed, especially for urban warfare in close quarters.

Will the Security Council resolution pass? Yes, of course, since the U.S., which has been the only veto in the Council’s resolutions against Israel so far, is actually proposing this resolution. And that bodes very ill for Israel.

We also see bizarre claims (viz., from Thomas “I am Dumb” Friedman) that creating a two-state situation will somehow miraculously bring about lasting peace, even when we know that neither Palestinians nor Israelis favor that situation, that it can’t work, and that polls show that most Palestinians, whether they be in Gaza or the West Bank, still favor Hamas.  Here are results from a poll taken between March 5 and 10 from the Palestinian Center for Policy and Survey Research:

Forced to the "brink of starvation" in a bombed-out hellscape, what do Gazans think of Hamas now?

New poll:

71% of Palestinians approve of the 10/7 Hamas attacks

91% say Hamas committed no war crimes

59% want Hamas to rule Gaza after the warhttps://t.co/GmkDrwDsaT

— i/o (@eyeslasho) March 21, 2024

Finally, there’s the world’s accusation that Israel is preventing humanitarian aid to Gazans, despite all evidence that Israel is allowing and facilitating that aid, while Hamas takes the lion’s share of it while also ensuring that more civilians are killed—its strategy from the beginning. In fact, Israel has even proposed using IDF soldiers to guard the aid-bearing trucks to prevent them from being hijacked buy Hamas.

Yes, it looks to a pro-Israeli American that the Western world has lost its collective mind, taking steps that will ensure a victory of Hamas, a barbaric, Jew-hating organization that not only oppresses its own people, but is sworn to kill all Jews and eliminate Israel. This is the organization that, apparently, the West is loath to dismantle.

This is my view, but it appears to be one shared by the former Guardian writer Melanie Phillips in a recent column. Phillips, once a liberal, left the Guardian and moved towards the center-right, for which of course she’s been damned. It’s even worse for “progressives” because she’s Jewish favors Israel in the war. But her latest Substack column (also in the Jewish News Service), which you can read by clicking the headline below, rings true.  In fact, she speaks of a “war” between the U.S. and Israel, though of course it’s a war of wills, not of weapons.

Her thesis:

As some of us have long feared and has now become undeniable, Israel is fighting not one but two wars of defence against a malevolent foe.

The first is against the axis of Iran and its proxies: Hamas, Hezbollah and the Houthis of Yemen. The second is against America.

The Biden administration is to construct a pier off the Gaza shore to facilitate the delivery of humanitarian aid. This week, Israeli TV’s Channel 14 reported that, astoundingly, the Americans have handed over the financing and management of this pier to Qatar, the founder, funder and protector of Hamas and therefore the godfather of the October 7 pogrom.

Channel 14 said the Qataris demanded that the new pier be built by a Gaza company named Al Hissi, which is controlled by Hamas.

Giving Qatar control of this pier would ensure Hamas continues to exist, enrich itself and attack Israel with an open route into Gaza. As Yigal Carmon, the founder of MEMRI, has written in horror: “The US has flipped sides, from Israel to Qatar.”

America could end this war tomorrow by telling the Qataris that unless they instruct Hamas to surrender and release the hostages, Qatar will forfeit its preferential treatment by the United States and will henceforth be treated instead as an international pariah.

Instead, America is feeding Israel into the Qatari jaws. The outcome, writes Carmon, will be escalation into a total regional war by Iran not only against Israel but America.

America’s action is so preposterous it’s hard to believe. Yet in any event, the Biden administration has already pivoted from supporting the destruction of Hamas to working for its ultimate victory.

The administration has been relentlessly pressuring Israel to admit more and more aid into Gaza, accusing it falsely of stopping the trucks and ignoring the fact that most of this aid is being stolen by Hamas to enable it to survive at the expense of the needy civilian population.

The United States is determined to impose rule in post-war Gaza by the Palestinian Authority, despite the fact that the Palestinian Authority’s ruling party, Fatah, has exulted at the October 7 pogrom and declared that it will continue such attacks.

The administration is determined to impose upon Israel a Palestine state, even though this would become another “Hamastan” and place central Israel in grave danger of October 7-style attacks on steroids.

And with Israel now poised to attack the last redoubt of Hamas in Rafah, which is key to the defeat of this genocidal enemy, America is subjecting Israel to intense pressure to abandon this final front of the war.

While many, including me, have imputed America’s waning support for Israel to Biden’s drive to get re-elected, Phillips thinks that the desire to depose Netanyahu is a stronger motivation.  She may be right, but that motivation is misguided. Right now Israel is in an existential battle, and the war is being prosecuted by not only military experts, but by a war cabinet that includes right-wing Netanyahu but also two left-wing Israelis (Ganz and Gallant), who were generals in the IDF. Netanyahu fought too, and acquitted himself well in battle, taking part in many actions and being wounded many times, though he never made general. At any rate, now is not the time to call for regime change in Israel, even if you think that the U.S. has the right to tell the Israeli people when and how to hold elections.

Chuck Schumer, who pretends to be a Jew who has Israel’s best interests at heart, also comes in for his share of Phillipsian opprobrium. Beside calling for Israel to depose Netanyahu, Phillips adds this:

Far worse, Schumer parroted the blood libels being used to demonise Israel by its enemies. Claiming to be one of the Jews who “love Israel in our bones,” he stated in the next breath: “I’m anguished that the Israeli war campaign has killed so many innocent Palestinians. I know that my fellow Jewish Americans feel the same anguish when they see the images of dead and starving children — and destroyed homes.”

Every civilian death in wartime is tragic. But “so many innocents” is based on Hamas casualty figures that inflate the numbers and totally omit the Hamas forces they include.

Even more nauseatingly, Schumer smeared Israel still further by intoning: “We must be better than our enemies, lest we become them.”

The suggestion that Israel is no better than Hamas is a pernicious lie spread by those who want Israel gone. In fact, Israel’s ratio of civilians to combatants killed is fewer than 1.5 civilians for every one combatant, far better than any other country’s army has ever achieved.

That ratio, the focus of the world’s ire, should actually dampen its ire. The ratio is astoundingly low, but of course although using it to indict Israel makes no sense, it supports The Narrative, which in the end sees Israeli Jews as white colonialist oppressors and Gazans and Hamas as oppressed people of color who are simply battling colonialism, occupation, and oppression. Phillips:

Israel is not just fighting to defend itself against genocide. It is on the front line of the west’s defence against its enemies and the defence of civilisation against barbarism.

Western liberals can’t acknowledge this because they can’t allow their unchallengeable orthodoxies of Palestinian powerlessness, “peace processes” and western iniquity to be destroyed. So they have turned on the Jews. Jewish suffering has to be erased because it gets in the way of the narrative.

That’s why the eruption of Palestinianism throughout the west is so shattering. People wonder why the forests of Palestinian flags at the incendiary anti-Israel demonstrations are in themselves so intimidating.

It’s because the Palestine cause is not two states side by side. Palestinian identity consists entirely of the intention to eradicate Israel by the hijack and appropriation of Jewish history. Palestinianism stands for the erasure of Jewish national identity and wiping the Jewish people out of their own historic homeland.

Perhaps the last paragraph is a bit hyperbolic, but not overly so given the Jew hatred taught to Palestinian children and the repeated rejection by Palestinians of a “two state solution.” However, I’m sure that there are decent Palestinians who merely want to live in peace with Israeli neighbors, and live in a prosperous country with a decent government. Unfortunately, Hamas won’t permit that.

And, apparently, neither will the United States.

**************

UPDATE: I’ve just learned that, against all expectations, the U.S.’s Security Council resolution at the UN did NOT pass—it was vetoed by Russia and China but of course the U.S. voted “yea”.

France will work with Jordan and the United Arab Emirates to convince Russia and China to back a resolution at the United Nations for a ceasefire in Gaza after the two big powers blocked a text by the United States, French President Emmanuel Macron says.

“Following the Russian and Chinese veto a few minutes ago, we are going to resume work on the basis of the French draft resolution in the Security Council and work with our American, European and Arab partners to reach an agreement,” Macron says at the end of a European Union leaders’ summit in Brussels.

France’s foreign ministry said on Thursday it had started drafting a resolution with diplomats, saying they would put a draft forward if the US resolution did not pass.

Earlier, the UN Security Council failed to pass a resolution calling for an immediate ceasefire in Gaza as part of a hostage deal, the first time the US has backed such language.

The resolution called for an “immediate and sustained ceasefire” lasting roughly six weeks that would protect civilians and allow for the delivery of humanitarian assistance.

I’m not sure why Russia and China voted “no”, unless it’s simply because they don’t like the U.S. and wanted to oppose its resolution.

Categories: Science

Largest recorded solar storm was even bigger than we thought

New Scientist Feed - Fri, 03/22/2024 - 5:00am
Rediscovered magnetic recordings reveal just how extreme the largest recorded solar storm in history, the Carrington event in 1859, really was, highlighting the danger such storms could present to us nowadays
Categories: Science

Ant queens have good reasons for eating their own babies

New Scientist Feed - Fri, 03/22/2024 - 3:00am
Feasting on family members may be an unorthodox way for ant queens to keep their fledgling colonies from being overrun by lethal fungi
Categories: Science

Male and female spiders pair up to look like a flower

New Scientist Feed - Fri, 03/22/2024 - 1:00am
Together, a dark-hued male crab spider and a larger, paler female resemble a flower, in what researchers suspect is the first case of cooperative mimicry
Categories: Science

Some Doctors Cared Much More About Sore Arms Than Cold Bodies

Science-based Medicine Feed - Fri, 03/22/2024 - 12:06am

The campaign against boosters was just a small part of a pathetic, pandemic-long pattern where doctors expressed grave concern about the mildest harms of measures to limit COVID, even purely theoretical ones, while being totally indifferent to literally anything the virus could do, including the deaths of children and young adults.

The post Some Doctors Cared Much More About Sore Arms Than Cold Bodies first appeared on Science-Based Medicine.
Categories: Science

How Evolution Matters To Our Health: A Practicing Physician Explores How We Evolved to Be Healthy

Skeptic.com feed - Fri, 03/22/2024 - 12:00am

“Nothing in biology makes sense except in the light of evolution.” —Theodosius Dobzhansky

Why can one person smoke and drink heavily into their 90s while another dies from cancer in their 40s? Why are we fat? Why does a suntan look and feel so good if it is bad for us? Why is alternative medicine so popular? Do vaccines work and are they safe? Do toxins in our food cause cancer?

In this article I outline the emerging field of Evolutionary Medicine, looking at how our Stone Age ancestors lived, got sick, and got well over millions of years, and pointing to how we can live longer, healthier, and happier lives today.

As a skeptic, I have learned to often question ideas that are accepted as “common knowledge.” As a physician, I know that some of the drugs and treatments that we are encouraged to use today are only marginally useful at times and sometimes even toxic. Where does evolution come in? I have found that applying evolutionary thinking to common medical knowledge can provide us with fresh insight into the cause and cure of common diseases.

Evolutionary medicine draws insights from three areas of scientific research: (1) archaeologists’ ongoing discoveries about the lives of our paleolithic ancestors; (2) anthropologists’ observations of modern humans living in cultures that have changed little since the Stone Age; and (3) findings of molecular geneticists that have unraveled the story told by our DNA.

These studies have led to fundamental changes in our understanding of what it means to be healthy. We now know that many problems we experience today are, in fact, understandable in terms of the natural capacities that helped us survive in earlier times. Evolutionary medicine can expose many fallacies behind commonly accepted medical practices and the quackery that fosters popular health fads.

What is Evolutionary Medicine?

Some time ago I was invited to co-teach a course in Evolutionary Medicine at the University of California, Santa Barbara. Professors of parasitology and evolutionary biology, Armand Kuris and Bob Warner, explained that they needed a “real doctor” in the class because their knowledge of human disease and medical treatment was understandably limited. Since inviting a practicing physician to join the mix aligns with the interdisciplinary approach for which UCSB has become known, how could I refuse?

We were fortunate to use the just-published Why We Get Sick as the course text. In it, evolutionary theorist George Williams and psychiatrist Randolph Nesse merged their knowledge of health and disease with emerging archaeology and evolutionary biology to begin answering questions about why rather than simply how we get sick.

It soon became impossible to avoid seeing my own patients as the not-so-distant descendants of our Stone Age forbears. From allergies to the most terrifying cancer, from the ravages of mental illness to the most mysterious autoimmune disease, Darwinian evolution was no longer simply an elegant theory. I was seeing its consequences daily: in the diseases from which my patients suffered but also in how they could be healed.

When I began to share these evolutionary insights with my patients—for example, how we heal from a sprained ankle or why so many people struggle with diabetes— it didn’t take long to see positive effects. These conversations often helped patients develop an entirely new approach to problems from which they’d long suffered as significant improvements in their health soon followed.

The Primal Diet

Consider your teeth. Many of the best-preserved fossils we have found are teeth. That’s because tooth enamel is the hardest, longest lasting substance in the body. These fossils reveal that Stone Age teeth had a rough time of it, undergoing wear and tear as tools for cutting and grinding and chewing many hours a day. Remarkably, however, they had few cavities, the number one dental problem we have today! Since cavemen didn’t have toothbrushes, fluoridated water, dental floss, or dentists, why were their teeth so healthy?

The answer is diet. The bacteria that rot teeth feed mainly on sugars. Unlike proteins and fats, sugars are tiny and sticky. Streptococcus mutans, the main bacterial culprit in tooth decay, lives in the crevices around our teeth and turns sugar into lactic acid that then erodes the surrounding dental enamel, leaving holes—or cavities—in which more bacteria can live. We know from genetic studies that S. mutans has existed in its current form for several million years. It has found a good niche, so why mutate?

When fibrous roots, sour fruits, and occasional honey were the only scarce carbohydrates in a paleolithic person’s diet, these bacteria found very little to feed on. In contrast, our modern diet, overloaded as it is with simple carbs and sugary sodas, offers a bacterial paradise. It’s no surprise, then, that dental cavities are the most widespread chronic disease of childhood in the world today.

This understanding about dental hygiene leads to one of the most frequent and important questions I hear in my practice. What should I eat? Our early human ancestors spent several million years gathering and chasing down every bite of food they ate. The reason we covet sweet, salty, and greasy foods today is that they are important for survival and were rare. Not so today. Simply by reaching into the refrigerator, in a few minutes we can snag all the calories we need to get through the day. We know that eating too much is bad for us, but we seem powerless to stop.

The problem is not just a lack of willpower. We spend billions of dollars a year on foods low in carbohydrates, fats, and sugars or high in vitamins, antioxidants, or omega-3 fatty acids—hoping they will help us lose weight. We dish out billions more on diets, unused gym memberships, surgery, and appetite suppressing injections. Meanwhile, our healthcare system is burdened with hundreds of billions spent on obesity-related illnesses. Gluttony may be a vice, but overeating is an epidemic fed by wholly modern myths about food.

In the past 50 years, we’ve witnessed a tidal wave of obesity as nutritionists, doctors and food manufacturers promoted a fear of fatty foods. But low fat doesn’t mean low in calories. And calories count. Making food with less fat often means packing in more carbohydrates to make it appealing. A low-fat label gives us the false impression that we can eat as much of these “harmless, healthy” foods as we want. But if there were an easy diet that really worked, we’d all know about it. We’d all be thin. The fact that so many diet books sell each year is all the evidence we need that none of them is universally effective.

What did our ancestors eat? We can calculate that to get enough calories our earliest primate ancestors spent up to 12 hours a day finding, chewing, and grinding mostly plant-based foods, much as gorillas do today. As they evolved, their diet expanded to include berries, grubs, fruits, eggs, mushrooms, and the occasional small animal when they could catch one. They were omnivores. We estimate that our ancestors consumed up to 300 different foods in a typical week; today we average about 30.

Many of the roots and vegetables on which ancestral humans thrived were loaded with what your mom might call roughage. Stone Age fruit bore little resemblance to today’s plump, sweet, and juicy produce. An apple then looked and tasted more like today’s hard crabapple. Berries were small, and archaic citrus fruits would make a sour lime taste sweet in comparison. Along with honey and later primitive grains, these fruits were the main source of carbohydrates. Before the advent of agriculture barely 12,000 years ago, most foods contained very few starchy carbs. Before people began cultivating wheat, corn, and rice, the wild versions of these grains grew sparsely, had thick husks, and produced few kernels containing little starch. Root crops were tough and required a lot of chewing. Nuts were tiny and bitter, more like today’s acorns. Fruits were scrawny, fibrous, and none too sweet.

Evolutionary Prescription for a Healthy Diet
  • Forget about a low-fat diet. Go low-carb instead. Minimize bread, cereal, pasta, potatoes, rice, beans, and other grains. None were on the menu in the Paleolithic.
  • Maintain a healthy weight and avoid obesity by restricting the number of calories you’re ingesting to what you burn.
  • Be omnivorous. Eat a wide variety of foods to ensure you get all the vitamins and minerals you need—without taking vitamin pills or supplements.
  • In the absence of gnawing on bones like a caveman, include dairy products and root vegetables for calcium.
  • If you are vegetarian for ethical reasons, you have to be very careful to avoid nutritional deficiencies, especially in children.
  • Throw all rules out the window on your birthday and other special occasions. Eat whatever you want and enjoy it.

Since fruit and grains appeared for only a few weeks each year, it was vital for our ancestors to eat as much of them as possible when available, before the birds, insects, and other animals could get to them. When fruit ripened, early humans gorged themselves until they were stuffed—then ate again an hour or two later. As a result, our ancestors evolved a nearly insatiable craving for carbohydrates. The only limit was the size of their stomachs, and those could stretch to accommodate the seasonal abundance.

During times of plenty, Stone Age people ate a whole lot more each day than they needed. Those whose bodies were better at storing up those extra calories as fat, bought some insurance for any lean times ahead and passed on their genes for getting fat on to the next generation. This cycle of abundance and want lasted for millions of years. We are its inheritors.

Paleoanthropologists love to debate, “Which came first, bigger brains or more protein in the diet?” We do know that as our ancestors became cleverer, they became better hunters. (Hunting and tracking may indeed be the evolutionary basis for our ability to think scientifically, but that is another, long story.) Eating animals added protein and fat to their diets, providing more calories often for less effort than eating plants. Before farming changed everything, abundant meat was the main course for hundreds of thousands of years.

Taming fire, roughly one million years ago, was a key evolutionary event. Cooking breaks down starch and proteins, making them easier to chew and digest. More energy became available from every bite. Quickly, time spent chewing dropped from 12 to 3 hours a day. This may have been the advent of leisure; time to sit around the fire and tell stories, sing, and pass along knowledge.

Only a few hundred thousand years after harnessing fire, early hominids set out on their first great migrations around the globe. Humans loved meat. In areas where game was abundant, some settled for tens of thousands of years. When meat became scarce, because of a changing climate, overhunting, or just bad luck, it was time to pick up stakes and search for happier hunting grounds. The disappearance of many species of large animals such as massive marsupials in Australia, ground sloths in North America, and bison, elk, and aurochs in Europe, followed the spread of modern humans.

By the late Stone Age, around 50,000 years ago, Homo sapiens emerged as accomplished and resourceful hunters. Studies show they got around half their calories from meat and fat, 40 percent from roots and vegetables, and 10 percent from fruits and berries. These humans, with bodies and brains similar to yours and mine, ate very well. It is from this time that we have evidence of the first obese people. There probably weren’t many of them, but a few were able to lead pampered, sedentary lives, supported by the advancing skills of the growing tribe. Sculpted images of enormously obese women, known as “Venus” figurines, are among the earliest surviving works of art, carved more than 30,000 years ago. Of course, we don’t know the exact meaning these images held for their late Stone Age makers, but it is likely that they were expressions of beauty, or at least attractiveness. Fat women have been cherished for their fertility in most cultures until very recently. “Survival of the fittest” might be better expressed as “reproduction of the fattest.”

Some hormones evolved to shut down our appetites when we had eaten enough fats and proteins. That is why fatty foods are so “satisfying.” However, others, such as GLP-1—the hormone that the new weight loss drugs Wegovy and Ozempic mimic so effectively—are released by sugar and carbs in our diet. They trigger the production of insulin and in our past helped us to pack away those excess carb calories as fat. In higher doses (mimicked by the weight loss injections) they slow down movement of food through the gut, making us feel “full” and thus suppressing our appetite.

Germ Warfare

Drop the word infection into any conversation and watch ears prick up. Mention diarrhea or COVID, and people will begin to edge away. Measles, mumps, or mononucleosis get little reaction any longer. However, up the ante with herpes, tuberculosis, or syphilis, and you can sense people starting to squirm. Invoke pus, bleeding, or plague, and you are edging beyond the bounds of polite conversation.

Most of us have a primal fear of infectious diseases, for good reason. Alongside medicine’s stellar achievements of the past few centuries—hygiene, antibiotics, vaccines, and vastly safer childbirth—many microbes have battled humans to a draw, and some are even gaining ground. As soon as we conquer one infectious disease, another seems to take its place. We defeat smallpox, arm-by-inoculated-arm, and HIV comes out swinging. COVID-19, a more lethal cousin of the common cold, caused us to apply dampers to the world economy for months. We are in an evolutionary arms race with no end in sight. As the human population rises, there are more hosts for our microscopic enemies to attack.

Even with the discovery of antibiotics less than a century ago, bacteria, parasites, and viruses have not retreated. Within a year of the first use of penicillin, some germs were found to resist it. And while vaccines have loosened the stranglehold once held on us by measles, mumps, hepatitis, and polio, as yet we have no shots to prevent HIV, herpes, West Nile, or a horde of other viruses. In the tropics, new strains of influenza emerge annually from animal hosts and spread at jet speed onto the wider world stage.

On the home front, patients come to me every day sneezing and coughing, aching and fevered, hoping an antibiotic will provide a quick fix. Sadly, these drugs have no effect against viral infections and, when used inappropriately, breed drug-resistant bacteria in our bodies. At the same time, some people worry that vaccines against the killer diseases of childhood actually damage their children. They resist immunizations, depending on others to get the shots that derail an epidemic.

Fighting infections has never been easy. Microbes invade our bodies and evade our immune systems in clever ways that science is still deciphering. In the past, they jumped from person to person, while today they leapfrog from city to city. They are nimble adversaries. Evolution happens when genes mutate and spread to the next generation—and many bacteria produce a new generation every 90 minutes!

Nevertheless, working in our favor are the very Stone Age defenses we often misunderstand. Our healthy skin, thick mucus, fever, inflammation, and antibodies are the body’s first responders on the front lines of the fight against infections. We suppress them at our peril. Understanding how our cave-dwelling forebears survived such onslaughts, long before they could reach for a bottle of pills, can teach us how to respond better to infections today.

A Few Paleolithic Symptoms That Have Lingered On

Coughing evolved to clear our airway of foreign particles—dust blown by the wind, smoke from a fire, and food inhaled when we meant to swallow. By forcefully expelling air from our lungs, coughing gets the grime out. A sneeze serves a slightly higher purpose.

Mucus, or phlegm, is also a defense mechanism. This complex and wonderful concoction of proteins and other gooey stuff entraps and disarms germs, helping us to swallow them into our stomachs where powerful acids wait to destroy them.

Evolutionary Prescription for Weight Loss
  • Eat fewer calories.
  • Eat fatty foods and proteins to satisfy your hunger, rather than starchy, sugary ones. Fats and proteins trigger satiety hormones and take more time to digest.
  • Fool your Stone Age appetite by filling up on bulky, low-calorie vegetables such as celery, radishes, and salads. Also, drinking warm liquids such as chicken broth can trick your body into feeling full for a while.
  • Watch out for fruit juice and sodas. They are mostly sugar and water.
  • Exercise because it’s enjoyable and healthy, but don’t rely on it to shed weight. You’d have to exercise for hours to work off a single sugary soda.
  • Eat meals whatever time of day you want to. A calorie is a calorie no matter when you eat it.

What happens when we are confronted with a cold virus? A virus is really very simple. It’s just a bundle of genes, wrapped in a protein coat. All it needs is to find a good place, i.e., you, in which to set up housekeeping, make a few million copies of itself, and then move on. For contagious diseases, it’s the moving on that matters. If they can’t get out of us to a new victim, they die out. Cold viruses such as COVID are spread on airborne droplets of moisture when we cough. Making us cough, by irritating our airways, is the evolutionary tactic a virus uses to spread itself. Diarrhea is a similar strategy of gut viruses, the “stomach bug.”

Well-meaning parents often encourage their sick children to “cough it up” to clear phlegm out of their airways. However, coughing actually irritates our airways. It’s like scratching an itch. The more you scratch, the more irritated it gets. Coughing actually makes a sore throat worse and spreads the virus to others. We are playing right into the virus’s hands.

Sneezing is even worse. Have you ever seen the famous photo of a sneeze, spraying droplets ten feet across a room? Sneezing serves the virus’s purpose by loading them on an express flight to the next victim—our children, coworkers, spouses, or strangers. This is why masks are useful in stopping the spread of airborne viruses. To really be helpful, however, you need a really good mask, such as an N95, made of multiple layers of hydrophobic filters that stop the droplets from ever reaching your nose.

When you feel the need to cough, don’t let the virus win. Suppress it. By drinking a small amount of liquid, you can help your body eliminate the germs by ingesting them. At the same time, you will prevent the irritation and swelling that coughing brings. Sometimes you can’t help but cough. In those cases, your mom had it right: Cover your mouth. Not just a polite hand in front of the face— really press your hand or inner elbow over your mouth to seal off any air from coming out. (And then be sure to wash your hand—thoroughly). This decreases the rapid flow that irritates your airway as well as stops the spread of germs. This was common advice 50 years ago when coughing around others was considered impolite at best.

Unfortunately, all the over-the-counter cough remedies containing dextromethorphan (the DM in Robitussin-DM) and other ingredients don’t do much. They coat your throat, but they don’t help suppress coughing. Without any evidence they are effective, we spend billions a year on cold remedies such as Echinacea, Airborne, vitamin C, Dayquil, Nyquil, antihistamines, decongestants, cough suppressants, and fever reducers that do nothing to shorten the infection and have minimal effect on the symptoms. Some even work against the healing process.

When we take an antihistamine to dry up the sniffles, it limits the mucus available to help engulf the virus. The sole over-the-counter expectorant used in the United States, guaifenesin, thins mucus, which makes it less effective at trapping bacteria. Codeine-based cough suppressants, now very hard to come by, can help and are useful when simply making an effort to suppress the cough fails, especially at night when we need to sleep.

The most effective way to defeat a cold virus is to recognize that we are all in this together. Once we’re infected, washing our hands and covering up when sneezing or coughing is the kindest thing we can do for others. Rest, stay hydrated, and let your immune system do what it evolved to do. When a true cure for the common cold comes along, it won’t need to be advertised or sold in alluring packages at the checkout counter. It will be obvious to all of us because of how well it works, every time. And then, like polio and smallpox, colds will be history.

You Give Me Fever

If evolution is a long war between us and germs, then a cold is a daily skirmish on the front line. While viruses reproduce quickly, our bodies react more slowly. It can take days for our immune system to mobilize specific antibodies to fight a virus.

Over millennia, we evolved a quicker response. Germs are adapted to infect us when our body temperature is normal. By turning up our internal thermostat when we first detect an infection, our bodies make it harder for the virus to grow. Shivering probably evolved to warm us when we got cold. A shaking “chill” making us hot—called a rigor in medicine—is often our first line of defense. When we feel a chill, we want to take to our beds because that is exactly what we should do. If we take a fever reducer, such as aspirin or Tylenol, we can suppress the fever and may feel well enough to be up and around. This can divert energy our body needs to fight off the infection—and affords the virus many more opportunities to spread to others.

Increasing our temperature also speeds up the activity and circulation of disease-fighting white blood cells. In early mammals, those who responded to microbe invasion by developing a fever and limiting their activity would have survived better and passed on these defenses to their descendants. It makes evolutionary sense that children get hotter faster than adults. Kids are more likely to run into germs they have never encountered before and to which they have no immunity. They need the quick general defense a fever can muster.

If a fever provides an evolutionary advantage for a near naked primate, what happens when we bundle up in blankets? We can cause our temperature to rise higher than it naturally would and so overshoot the safety mark. Exceeding 103F (39.5C) degrees can do more harm than good. Extreme temperatures can lead to seizures in children and dehydration and worse in adults. Taking a fever reducer such as aspirin, acetaminophen (Tylenol), ibuprofen (Advil and Motrin), or naproxen (Aleve) is entirely appropriate in these conditions. These medications all short-circuit our body’s natural ability to raise a fever.

Is there any sense in the old saying, “feed a cold and starve a fever”? When we have a simple cold, eating has been shown to quadruple the production of the virus-fighting hormone interferon. When we start to get hot, however, it’s not food we need but fluids. It’s no coincidence that a fever kills our appetite. Fluids trigger the production of interleukin-4, which works particularly well against many of the bacteria that cause fevers. The return of hunger is usually a sign that you are getting better.

A Paradox of Prevention

Polio offers a good example of how “progress” can inadvertently help a virus to spread in a way that evolution couldn’t. Polio is a virus that usually grows in our guts. When excreted, it survives for weeks in freshwater pools and stagnant ponds.

Throughout history, infants who were exposed to the virus early in life while they were still protected by antibodies in their mothers’ milk, usually experienced only a mild infection. Fewer than one in a thousand had the paralytic form associated with the epidemics of the last century.

Paradoxically, modern hygiene in the late nineteenth century prevented infants from ingesting water contaminated with the virus while still breastfeeding. Coming in contact with that virus later in life in swimming pools or ponds, at a time when they were no longer protected by maternal antibodies, caused them to contract the much more serious paralytic form of the disease. By 1900, small epidemics of paralytic polio began to appear throughout the industrialized world. By 1952, with breastfeeding at a minimum and better sanitation more widely practiced, polio infected thousands of children who had failed to acquire immunity in infancy. At its peak in 1950, the epidemic paralyzed 60,000 people a year.

A vaccine developed in 1952 by Jonas Salk arrested the spread of the disease within a few years. Polio is now almost wiped out. However, certain religious and political objections still hamper universal use of the vaccine.

Other diseases that could be eradicated, linger on—mumps, measles, chickenpox, and hepatitis. As vaccination has made certain childhood infections so uncommon in Western countries, some people have become comfortable with not vaccinating their children. These parents are counting on the immunity of those who do get vaccinated (herd immunity) to prevent the spread of these childhood illnesses to their own kids.

Evolutionary Prescription for Toxins
  • Be very careful with the dose of all drugs—prescription, over-the-counter and recreational. All can be toxic.
  • Unfortunately, alcohol is a toxin. Newer evidence suggests the less the better.
  • Get all the vitamins you need from sunshine and a healthy diet, not pills or supplements. Vitamins are essential but can be toxic in large doses.
  • Don’t worry about toxins in peanut butter.
  • Don’t obsess about buying “organic.” As far as your health is concerned, there is no difference between organic and nonorganic.

Remember measles? Measles ranks high on the list of all-time lethal diseases. By some estimates, measles wiped out up to a third of all the people along the trade routes of the Middle Ages—and that was even before the European Age of Exploration opened vast new territories for the virus. In the past 150 years it has killed 200 million people—including 128,000 in 2021, most under the age of five.

The measles virus evolves very slowly. With so many innocent immune systems to infect in the past, it didn’t need to change much to find plenty of hosts. Luckily, it’s easier to make vaccines for slower-changing viruses because they are so stable. Faster-changing viruses, such as COVID, HIV, and influenza, form more elusive moving targets.

Today, many of us have forgotten how dangerous many formerly common infections were. Measles was a worldwide scourge. Mumps can make men sterile. Rubella can cause birth defects when it infects a pregnant woman. One vaccine, MMR, prevents all three. Diphtheria and Whooping Cough (Pertussis) were once dread diseases of childhood. Tetanus kills. Here too a single vaccine, DPT, prevents all three. Smallpox, which killed 300 million people in the last century, has now been eradicated by a worldwide vaccine campaign.

By skipping vaccination, some parents hope their children will dodge a risk. However, serious side effects of the vaccine occur at a much lower frequency than serious complications of the disease. Fears once raised that measles vaccine causes autism have been thoroughly debunked.

If enough people avoid vaccination, those once serious diseases will continue to evolve and come roaring back. Mumps and whooping cough are returning to the United States. Polio is still making its crippling rounds. Skipping vaccination is a terrible gamble. When these viruses strike, unvaccinated children are the first to fall.

During the COVID-19 pandemic, the science of vaccination became even more politicized. This is unfortunate because priming our immune systems to recognize and fight off infections is one of the most effective and least harmful methods of protection we have. In the Stone Age, every infection set off a race between the “bugs” and our defenses. Vaccines activate this age-old system by injecting tiny amounts of weakened strains of these germs, allowing us to be forearmed.

The Not So Common Cold

Colds are caused by viruses—not by being out in cold weather or getting tired or soaked with rain. Understanding the evolutionary origins of viruses can help us stop them in their tracks. Most cold viruses evolved in enormous prehistoric populations of migrating birds and beasts. Because there were millions of animals in these flocks and herds, viruses could spread from one individual to another, never needing to infect the same creature twice—much like a wave spreading across the water.

By contrast, our paleolithic ancestors lived in isolated bands of a few dozen people. Archaeologists estimate that as recently as 70,000 years ago there were only 10,000 humans alive on the entire planet. Each family or clan clung together as closely as possible, seldom interacting with other groups. Stealing food or mates posed too great a risk to encourage much contact. So even if an animal virus managed to infect a person, it was very difficult for it to spread beyond the group it first entered. The common cold was not so common back in the Stone Age. Clearly, we aren’t going to solve the problem of colds by going back to living in isolated tribes. However, the insights of evolutionary medicine can help in arresting the rapid spread of these and other viruses in our modern world.

Under the Influenza

Influenza, the “flu,” kills around 400,000 people worldwide, and 36,000 people in North America—most years. In flu pandemics, which occur every 20 years or so, tens of millions die.

As with the common cold viruses, the earliest humans didn’t have enough contact with other groups to allow the flu to spread. Yoshiyuki Suzuki (Oxford University), who studies the evolution of influenza, estimates the first flu epidemics in humans occurred no earlier than 8,000 years ago. This coincided with the development of farming and village life, when people, fowl, and pigs first began living cheek by beak by jowl.

Unlike the more stable measles, mumps, and chickenpox viruses, the flu virus changes its outward appearance (that is, it evolves) rapidly. Shrouded in an ever-varying coat of proteins, like a shape-shifter in a science fiction novel, it cloaks itself in order to hide from our immune systems. However, once it gets past our defenses, it always causes the same miserable symptoms—high fever for days, severe body aches, a racking cough, and nasal congestion. It’s like a cold, only much worse.

Flu’s ability to change its surface coat so rapidly forces us to come up with a revised flu vaccine every year. Modern medicine maintains a constant watch for emerging strains in order to predict which to include in the following year’s vaccine. Before the advent of annual flu vaccines, many more people got sick and died of the flu every year, especially those over 60.

Occasionally, farmers and food handlers are infected with a strain of flu derived from another animal at the same time they have a human flu virus in them. When this happens, the two kinds of flu can merge to become an entirely new strain. The combined virus is often better at infecting us because we have no antibodies that recognize its novel appearance. This is how the avian flu pandemics of 1918, 1957, 1968 and the swine flu pandemic of 2009 occurred, and also why some people think COVID-19 originated in a live animal food market in China. (Doing justice to the debate between the “wet market” and the alternative “lab leak” theory of the origin of COVID-19 requires a separate article).

Quarantine, an early scientific method for halting the spread of disease, yields excellent results—if it is done quickly enough. That’s how SARS, the first well-known Coronavirus, was stopped in 2003. With proper public health policies in place, and enough people who take them seriously, we could likely contain any newly emerging virus within weeks, even a novel strain of the flu, without relying on vaccines. However, quarantine is expensive, inconvenient, and may even deprive people of some rights or even their livelihood for a short period. Still, that price would be minuscule compared to the devastation of a full-blown pandemic such as we have recently experienced.

On the home front, the best way to protect ourselves is to be clear about how such germs spread. Not being “part of the herd” and not going out in public when we are sick can go a long way toward stopping the spread. Covering our mouths when we cough or wearing effective masks helps a lot, as does thoroughly washing with plain old soap and water. Washing is a lot more effective than hand sanitizer, which doesn’t kill all types of viruses or even fully remove them from our hands.

Toxins and Cancer

Many things in our world are toxic. Radium, benzene, arsenic, and asbestos are widely known to cause cancer, but most of us are rarely exposed to them. On the other hand, smoking, drinking, obesity, and excess sun exposure together account for about 50 percent of all cancers.

The most significant food toxin known to cause cancer in humans is Aflatoxin, a fungal byproduct found in moldy peanuts. It contributes to the occurrence of liver cancer, mostly in parts of Africa and Asia where the hepatitis B virus, a cofactor for this cancer, is prevalent and moldy food is common. Yet, if you search online, you will find a long list of alleged cancer-causing culprits, including soda, hydrogenated oils, microwave popcorn, farmed fish, refined sugar, white flour, pickled, salted or smoked foods, and grilled red meat. We frequently hear that some common chemical such as the sweetener we use in our coffee “causes cancer.” None of these claims is backed by scientific evidence.

Evolutionary Prescription for Cancer
  • Watch your weight. Obesity hikes the odds of several cancers.
  • Exercise at least 30 minutes a day, three times a week, to lower your general risk of cancer by about 10 percent.
  • Keep vitamin D levels up to snuff by getting 30 minutes of sun three days a week on parts of your body not usually exposed.
  • Don’t smoke. You’ll decrease your lifetime risk of lung cancer by 90 percent and your overall risk of dying of any cancer by 25 percent.
  • Get a colonoscopy after age 50. You’ll decrease the risk of dying from colon cancer by 80 percent.
  • Lower your chance of getting some cancers by a third by saying no to antioxidant and vitamin supplements—particularly A, C and E.
  • Girls and young women: Say yes to the new HPV vaccine. It reduces the risk of cervical cancer by 95 percent.

When scientists say a chemical “may cause cancer,” it usually means it was tested and found to damage the DNA of a bacteria or cause tumors in rats. However, such research uses doses hundreds or thousands of times what a person would ingest, pound-for-pound. And rats are genetically different from you and me. They get cancer very easily and that’s why we use them for tests. Just showing that a toxin causes cancer in rats, or abnormal changes in bacteria or cells in a Petri dish, doesn’t come close to demonstrating it will do so in humans. Our livers are three times the size of the whole rat and work hard to protect us. Please don’t misunderstand what I’m saying. I am a scientist. I trust good evidence. However, not all research is done well and we must remain skeptical—though not cynical—especially of fear-inducing claims.

Since we can’t ethically test toxins on humans, we look for “natural experiments”—groups of people exposed to a chemical at work or by accident. We then compare them against a similar but unexposed group to see what effects these toxins have. Beyond a few well-studied carcinogens—and Erin Brockovich’s cinematic arguments about a cancer cluster—there is scant linkage between trace toxins in our environment or food and cancer or other illnesses.

Your plastic water bottle, for example, won’t give you cancer. If it did, we would have detected thousands, indeed millions, of cancer cases already. The same is true for tap water. There’s no credible evidence that food preservatives, deodorant, stress, aluminum, processed foods, aspartame (Equal), or saccharin (Sweet’N Low) cause cancer. If you examine the reports carefully you will see that they are usually based on extrapolating from experiments on cells or animals given huge relative doses and always contain qualifiers such as “can” or “may” cause cancer.

We have always lived in a world chock full of poisons, and we have evolved potent defenses against the natural threats we’ve encountered in our long ascent from the primordial swamp. Our not so fragile forebears thrived among greater toxic threats than we might imagine. Why do some things smell and taste “bad”? Often it’s because they were bad for us. Our tough skin, hardy livers, and purifying kidneys evolved to neutralize many toxins that passed the nose test to make their way past this first line of defense.

Meanwhile, there is no shortage of products being offered to help our bodies “cleanse” ourselves of toxins by using homeopathy, chelation, or colonics. We can buy “probiotics” to counter the antibiotic we took when we had a cold. (The marketers don’t mention that all yogurts have these bacteria—it’s what makes them yogurt in the first place.) We can sweat in saunas, chill in ice baths, soak in spas, or spend money on supplements—all in the name of “cleansing.”

Is there any real evidence that people who make such efforts are healthier than the rest of us? Not one bit. Contrary to countless celebrity testimonials, decades of research provide zero evidence that using any detoxifying products actually improves health or prevents cancer.

Dodging Cancer

There’s a good evolutionary reason why we heal so well from wounds and infections but have trouble fending off cancer. Natural selection, the weeding out of harmful traits, has a hard time acting on illnesses that occur later in life. By the time most cancers appear, people have usually finished having children. A cancer predisposition that appears only after our reproductive years gets a free pass to the next generation.

Children do get cancers, of course. Terrible as these cases are, fortunately they are rare compared to other causes of death. Most cancers occur in older people. The single most important reason cancer is increasing in the developed world is because we are living longer, not because of toxins in our food and environment.

Cancer still kills one in six people worldwide, but that means 84 percent of us will die of something else. In less-developed countries where life expectancy is shorter, most people die of infections and accidents, as in times past. In those places, cancers don’t even make it into the top ten causes of death.

While research has made significant progress against certain cancers, our fear leaves plenty of openings for a Pandora’s box of alternative therapies. This has always been the case with poorly understood diseases. In the days before the discovery of the poliovirus, rumor attributed polio to everything from fleabites to airborne toxins, insecticides, and poverty. When the vaccine came along, some people thought it was the cause. Many of these same suspects are blamed for cancer today.

One popular theory suggests that a diet low in fiber causes colon cancer. This idea arose from a 1979 book that reported a lower rate of colon cancer in men in Africa than in the West. The author attributed this to their high-fiber diet and using a squatting posture during defecation. He forgot to take into account that men in Africa die younger than men in the West, and the rate of colon cancer increases as we age. A meta-analysis of more than 80,000 participants demonstrated that fiber doesn’t prevent colon cancer. Still the myth lives on in health food stores and breakfast cereal ads.

Antioxidants are now popularly claimed to prevent cancer (as well as aging, heart disease, and “inflammation”). These molecules do limit oxidation, a kind of cell damage that can contribute to cancer—in the lab. Remember, however, oxidants and free radicals are part of how our cells fight off infection and clear damaged cells from our bodies! When tested in people, there is no evidence that antioxidants—including beta carotene, lycopene, acai berries, cumin, turmeric, or vitamins A, C or E—can prevent cancer. Vitamin A in excess can cause liver damage, osteoporosis, hair loss, dry skin, and birth defects. It seems our bodies make all the antioxidants we need, so supplementing them can make matters worse. Studies done in actual people, not Petri dishes, show that excess vitamin E, folic acid, and beta-carotene can actually increase the risk of cancer.

Vitamin Supplements

Our Stone (and Iron, Bronze, Middle, and Steam) Age ancestors survived without ever taking vitamin pills, but it wasn’t always easy. In hard times, especially when they roamed into new territory, experienced harsh winters, droughts, and floods, food could be hard to find. Their bodies evolved to be very good at absorbing whatever vitamins they needed, especially when they were in short supply. We inherited this ability to store most vitamins for times of scarcity.

Today, of course, we can buy a plethora of vitamins and minerals off the shelf, mixed in myriad combinations. Some of us gulp down enough to choke a horse. This is a high-risk endeavor because an excess of certain vitamins (A, D, E, and K) can be toxic. Some of our legislators are enthusiastic supporters (read: on the payroll) of the vitamin industry. Vitamins are sold as “dietary supplements,” not as drugs, and are largely unregulated. There are no safety inspections or uniform requirements for those who manufacture or market them, and therefore no guarantee you are getting what you pay for.

This article appeared in Skeptic magazine 28.4
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The only real proof we need for the benefit of vitamin pills should be that taking them makes us healthier. However, people who take them, in small or mega doses, are sick just as often and have just as many other illnesses as those who don’t. Of the 13 known vitamins, six can be taken in overdose. Every year more than 60,000 people in the United States overdose on vitamins—80 percent of them are children under the age of six.

If you eat a variety of unprocessed food you get all the vitamins, minerals, and antioxidants you need. Let your body do all it evolved to do, and you will get just the amounts you need.

Alternative Medicine

Many “alternative” therapies, such as acupuncture, massage, Reiki, homeopathy, aromatherapy, naturopathy, and ayurveda promise to make us well while causing less harm than medicine. Do they work?

As most doctors and some alternative practitioners know, most people who seek medical attention get better on their own, no matter what we do to them. This is because most illnesses are mild and self-limiting. Still, many of us are not content with letting nature take its course. When we feel a sniffle, we reach for some over the counter medicine. None can make us better. When we get better, we want to believe it was because of what we took.

We spend billions each year on brand named pills and folk remedies that have lingered from earlier times. They became popular in the same manner as do all superstitions. One person tried them, got better, and believes the treatment worked. They pass this along through retelling and retailing, and so a so-called cure is born.

Alternative medicine practitioners now use TikTok, YouTube, Facebook and X (Twitter) to speed the spread of their “cures.” Although some of these practices are actually harmful, the false hope they offer to the seriously ill is misleading at best and criminal at worst. Sadly, modern medicine has sometimes been little better, pushing marginally useful pills or physical therapy on us when time and a better understanding of the natural process of healing would accomplish just as much—and at less risk and a lower cost.

What’s Next?

If you find this approach intriguing, I urge you to look further into what evolution has to say about how we heal from injuries, why allergies are more common today than in earlier times, how much sleep we really need, who we find sexually attractive, the benefits of grandparents, how many periods should a woman have in her lifetime, why morning sickness was good for us, why we get depressed, the advantages of Attention Deficit Disorder, what use are emotions, the origins of anxiety, whether cholesterol is really bad for us, why do so many people need glasses, how does sickle cell disease protect some people from malaria, and what can we do to live longer healthier lives. These topics and dozens more are the subject of the fascinating new science of Evolutionary Medicine.

About the Author

William Meller, M.D., is a board-certified internist who runs a medical practice and clinic in Santa Barbara, CA, where he also coordinates three busy medical centers. He has been published in The Journal of the American Medical Association and has been featured in the Wall Street Journal, among other publications. He is the author of the book Evolution Rx: A Practical Guide to Harnessing Our Innate Capacity for Health and Healing.

Categories: Critical Thinking, Skeptic

Europa Might Not Be Able to Support Life in its Oceans

Universe Today Feed - Thu, 03/21/2024 - 6:40pm

Can Europa’s massive, interior ocean contain the building blocks of life, and even support life as we know it? This question is at the forefront of astrobiology discussions as scientists continue to debate the possibility for habitability on Jupiter’s icy moon. However, a recent study presented at the 55th Lunar and Planetary Science Conference (LPSC) might put a damper in hopes for finding life as a team of researchers investigate how Europa’s seafloor could be lacking in geologic activity, decreasing the likelihood of necessary minerals and nutrients from being recycled that could serve as a catalyst for life.

Here, Universe Today speaks with Henry Dawson, who is a PhD student in the Department of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis and lead author of the study, about his motivation behind the study, significant results, follow-up studies, and whether Dawson believes there’s life on Europa. So, what was the motivation behind this study?

Dawson tells Universe Today, “A large portion of the community has been looking at the habitability potential of the seafloor, and looking at processes that might occur at seafloor hydrothermal vents, or at water–rock interaction chemistry. However, it was never established that there would actually be any fresh rock exposed at the seafloor, or if the tectonic processes that drive hydrothermal vents would be present. The silicate interior of Europa is a similar size to that of Earth’s Moon, which is largely geologically dead on the surface.”

Artist’s cutaway illustration of Europa and its potential geologic activity. (Credit: NASA/JPL-Caltech/Michael Carroll)

For the study, Dawson and his colleagues examined the likelihood for geologic activity occurring on Europa’s seafloor through analyzing data on Europa’s geophysical characteristics and comparing them with known geologic parameters and processes, including the strength of potential fault lines and fractures within Europa’s rocky interior, how the strength of this rock changes with depth, and how the rock could react to ongoing stresses, commonly known as convection. Using this, they conducted a series of calculations to ascertain whether the seafloor crust could drive geologic activity. Therefore, what were the most significant results from this study?

“It looks a lot more difficult to expose fresh rock (which is required to drive the reactions that life would exploit) to the ocean,” Dawson tells Universe Today. “Tidal forces do not seem able to cause motion along faults, like it can on the surface, and so the seafloor is most likely still. All the rock that water is able to interact with through porosity was likely altered hundreds of millions to billions of years ago, and so the ocean and rock are in chemical equilibrium. This means that there is no present day, continuous input of nutrients into the ocean from the rocky core, and so any possible life would likely have to exploit nutrient input from the icy shell above the ocean.”

While this study focused on geologic stresses related to fractures and fault lines, Europa’s interior ocean is produced from another type of geologic stress known as tidal heating, which is induced from the constant stretching and compressing as Europa orbits the much more massive Jupiter. This same tidal process occurs between the Earth and its Moon, and we see this in action in the rising and falling of the Earth’s waters around the globe. For Europa, over the course of thousands to millions of years, the stretching and compressing leads to friction in Europa’s inner rocky core, which leads to becoming heated and melting the inner ice into the interior ocean that exists today. It is in this ocean that astrobiologists hypothesize that life could exist, possibly even life as we know it.

However, given these study’s unfortunate findings, Dawson and his colleagues give dire implications for the potential habitability on Europa, noting their calculations estimate that geologic activity on Europa’s seafloor is limited enough to indicate habitable conditions within Europa’s interior ocean could be limited, as well. However, the study was quick to note that other geologic processes could be examined to explain the present state of Europa’s seafloor geologic activity, including processes known as serpentinization and thermal expansion anisotropy.

“As rock is exposed to water and chemically alters, the new minerals that form may have a different molar volume than the unaltered minerals in the original rock,” Dawson tells Universe Today. “Serpentinization specifically is the process where peridotite, a typical mantle rock, is altered to serpentinite. This reaction has a net volume increase, which introduces new stresses. These stresses might lead to the fracturing of the rock, fresh rock faces exposed, and more alteration, leading to a self-propagating cycle. On the other hand, the new minerals might cement up pre-existing fractures, preventing further exposure, and creating a negative feedback loop. Thermal expansion anisotropy describes the process where different minerals have varying degrees of expansion upon heating. Thus, when a rock is heated or cooled, the mineral grains inside will push against each other, introducing porosity and interior stresses.”

Regarding the tidal forces responsible for producing Europa’s interior ocean, this icy moon and the Earth’s Moon are not the only planetary bodies in the solar system that could experience these unique forces. Others include Jupiter’s third Galilean Moon, Ganymede, Saturn’s icy moon, Enceladus, and Saturn’s largest moon, Titan, all of which are currently hypothesized to possess interior oceans from tidal heating. Like Europa, Ganymede exhibits a predominantly crater-free surface, which is indicative of frequent resurfacing, and Enceladus was observed on numerous occasions by NASA’s Cassini spacecraft to have geysers on its south pole region that frequently shoots out water into space.

Additionally, Cassini flew through these geysers to obtain data on the ejecta’s composition, discovering organic molecules. For Titan, Cassini data revealed that an interior ocean exists beneath its surface, which is currently hypothesized to contain a combination of ammonia and salts. But regarding this most recent research, what follow-up studies are currently being conducted or planned?

Dawson tells Universe Today, “I’m currently using the same model to estimate whether tidal forces are able to cause fracturing on other icy moons in the outer solar system, such as Ganymede, Enceladus, Titan, and the mid-size Uranian moons. Based on my preliminary results that I presented at LPSC, it appears that tidal forces are insufficient on those moons as well. In addition, our collaborator Austin Green is looking at whether seafloor volcanism might occur, based on the forces that volcanic dikes can exert on the rock that they are propagating through. For Europa, the lithosphere is too deep and too strong for magma to reach the seafloor, and so any melt that forms in the mantle stalls out at depth.”

Despite being discovered by Galileo Galilei in 1610, the fascination for finding life within Europa’s ocean has only come within the last few decades, thanks largely to the NASA Voyager missions, with Voyager 1 and Voyager 2 flying through the Jupiter system in 1979 and imaged the Galilean Moons up close and in detail for the first time, hinting that Europa was currently geologically active. This is because Europa has almost no visible craters throughout its entire surface, indicating specific processes are responsible for reshaping the small moon and covering up evidence of past impacts. Europa, being the second Galilean Moon, shares these traits with the first and third Galilean Moons, Io and Ganymede, respectively, while the fourth Galilean Moon, Callisto has a surface that is almost entirely covered by craters.

The Galilean moons of Jupiter: Io, Europa, Ganymede, and Callisto. (Credit: NASA/JPL-Caltech)

Thanks to further data obtained from proceeding missions, including NASA’s Galileo spacecraft, Hubble Space Telescope, and Juno, scientists are almost entirely convinced that an interior ocean lies beneath Europa’s icy crust, with some estimates putting the volume of liquid water at double of Earth’s oceans. Therefore, as we see on Earth, liquid water means life, which is why Europa’s interior ocean is a target for astrobiology research. But does Henry Dawson think there’s life on Europa?

Dawson tells Universe Today, “I think there’s still a lot more that I would like to understand before I make a yes or no statement on that. While I believe that Europa is one of the most likely candidates to host life, alongside Enceladus, the chance of life remains small, and this research reduces the probability even more.”

This study comes as NASA prepares to launch the Europa Clipper spacecraft this October with a planned arrival date of April 2030 and is designed to explore the habitability potential of Europa and its interior ocean. During its 3.5-year mission, Clipper will perform up to 44 close flybys of Europa ranging between 25 and 2,700 kilometers (16 to 1,678 miles) as the spacecraft will perform elongated orbits to keep from staying within Jupiter’s powerful magnetic field for too long. To assess Europa’s habitability potential, Clipper will carry a powerful suite of scientific instruments designed to analyze Europa’s chemistry, surface geology, and interior ocean characteristics.

Artist’s rendition of NASA’s Europa Clipper (published in January 2021). (Credit: NASA/JPL-Caltech)

Additionally, the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission was launched in April 2023 with a planned orbital insertion at Jupiter in July 2031, followed by a departure from Jupiter and an orbital insertion around Ganymede in December 2034. Like Clipper, JUICE is designed to investigate the habitability potential of the icy moon, but will also examine Ganymede and Callisto, as well.

“Get excited for the Europa Clipper and JUICE missions! Dawson exclaims to Universe Today. “While it will still be 6 years before they reach Jupiter, once they arrive, we will be able to learn much more about what is going on at Europa. While they will not be able to directly measure the interior, observations of the ice shell, gravity field, and tidal forcing on Europa will help to constrain future models. As well, always be careful about the assumptions you make for other planetary bodies. While Europa may be covered with ice, it is truly a rocky world that happens to have a deep ocean, and the processes occurring at depth may not reflect what we see at Earth’s seafloor.”

Is Europa’s seafloor geologically active, and what new insights will Europa Clipper and JUICE make about this astonishing and intriguing icy moon in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Europa Might Not Be Able to Support Life in its Oceans appeared first on Universe Today.

Categories: Science

What Can Europa’s Surface Tell Us About the Thickness of Its Ice?

Universe Today Feed - Thu, 03/21/2024 - 3:12pm

You can tell a lot about a planetary body just by looking at its surface, especially if it has craters. Take Europa, for example. It has a fairly young surface—somewhere between 50 and 100 million years old. That’s practically “new” when you compare it to the age of the Solar System. And, Europa’s icy crust is pretty darned smooth, with only a few craters to change the topography.

Planetary scientists already know that Europa’s icy surface is a thin shell over a large interior ocean of salty water. How thin? To find out, a team of researchers led by Brandon Johnson and Shigeru Wakita at Purdue University studied images of large craters on Europa. They used what they saw, coupled with a variety of physical characteristics, to create computer models of that shell. “Previous estimates showed a very thin ice layer over a thick ocean,” said Wakita. “But our research showed that there needs to be a thick layer—so thick that convection in the ice, which has previously been debated, is likely.”

The thickness of that shell may well influence whether or not life exists at Europa. Its existence is a topic of intense interest since Europa could provide a reasonably habitable ecosystem for life. It has water, warmth, and organic materials for life to eat. That makes the search for life at Europa quite important. So, what do craters have to do with all this?

More About Craters

Impact cratering performs a lot of gardening in the Solar System, according to Johnson. He is the first author on a recently published paper discussing these features on Europa. “Craters are found on almost every solid body we’ve ever seen. They are a major driver of change in planetary bodies,” he said.

Four featured craters among many on the Moon: the triplet of Theophilus, Cyrillus and Catharina and Maurolycus. Many more craters can be seen across the lunar surface. Credit: Virtual Moon Atlas / Christian LeGrande, Patrick Chevalley

Just looking at images of different worlds in the Solar System, we can see some pretty heavily cratered surfaces. The Moon is a good example, as is Mars. And, we see it at many of the smaller bodies, such as the moons of the gas and ice giants. The more craters we see, the older the surface. In some places, multiple overlapping craters indicate a very old surface. In other places, such as at Europa, the craters are fewer and farther between. Something has “paved over” the craters such that any we CAN see were made after the repaving event. In addition, the craters reveal information about the surface as well as the “subsurface” of Europa.

“When an impact crater forms, it is essentially probing the subsurface structure of a planetary body,” said Johnson. “By understanding the sizes and shapes of craters on Europa and reproducing their formation with numerical simulations, we’re able to infer information about how thick its ice shell is.”

What Europa’s Craters Tell Us

This tiny moon is an enigma wrapped in shimmering ice. Its frozen surface hides a rocky inner core covered with a salt-water ocean. Like Earth, it experiences surface plate tectonics, driven by the core region’s heating. Inside, that heating drives currents of warmer water up from the core. That water gets forced to the surface, where it freezes and creates a new layer overlying any other features. This resurfacing happens every 50 to 100 million years.

Incoming impactors carve out new craters in that “freshened-up” surface, which gives scientists some pretty easy-to-study craters. They aren’t terribly deep, however, which tells scientists a lot about the structure of the icy shell. Johnson, Wakita, and their team studied images from the Galileo spacecraft to analyze Europa’s craters. In particular, they focused on two multi-ringed basins imaged on this moon. They show two or more concentric rings around the point of the impact that created them. Such basins are fairly rare and usually indicate some kind of large, energetic impact. On Europa, their appearance and formation give clues to the thickness of the icy shell and their thermal structure, which is a way to understand how the shell conducts heat.

Multi-ringed Crater Basins Tell a Tale

In their study, the Purdue team simulated a multi-ring basin with varying thicknesses of ice. Those thicknesses influence the degree of tidal heating in the shell itself. They also help scientists understand how heat exchange occurs between the bottom of the shell and the underlying ocean. The team found that icy shells thinner than about 15 kilometers don’t show the kinds of multi-ringed basins that exist on Europa. However, a thicker one does. In particular, the best-fit simulation used a 20+ kilometer-thick shell. It consists of two layers: a 6-8 kilometer-thick conductive “lid” that covers up a layer of warm, convecting ice.

One of Galileo’s images of the Tyre multi-ringed basin on Europa. There are at least 5-7 rings around the impact crater center. Courtesy: NASA/JPL/ASU.

In addition to studying the craters, the team also looked at the types of impactors needed to create those multi-ringed basins on Europa. From the structures seen in the Galileo images, they concluded that the impactors would need to be around 1.5 kilometers in radius to create the multi-ringed basins. Smaller ones wouldn’t create the structures they saw, and bigger impactors would result in very different-looking craters and rings.

What About Other Worlds?

Europa isn’t the only world at Jupiter with an icy crust. Both Ganymede and Callisto also show cratering, with multi-ring basins. This tells us that these worlds also have to have thick enough icy crusts where such basins can form. Planetary scientists have suggested their crusts are at least 80 to 105 kilometers thick. In their paper, the Purdue teams suggest that since Europa’s crust is likely to be at least 20 kilometers thick (if not more) it’s also likely that Ganymede and Callisto have much thicker crusts than current predictions suggest.

Callisto has many more craters than Europa and a thicker icy crust. Image credit: NASA/JPL

Finally, although the paper doesn’t specifically address this, the fact that the scientists can deduce impactor size from the characteristics of the resulting craters does provide insight into the sizes of impactors available in Jovian “airspace”. To sustain these kinds of multi-ringed basins, you need a good population of sizable impactors to do the job. Also, for Europa to be so recently “refreshed” really does give a clue to the impact environment in the Jupiter system. While Ganymede and Callisto both have very old surfaces, the existence of “fresh” ice at various cratering sites tells us that they’re still being bombarded in recent times, although they’re not actively resurfacing themselves. These are all additional data points to consider when understanding the habitability of environments, particularly at Europa (and possibly at places such as Enceladus at Saturn).

“Understanding the thickness of the ice is vital to theorizing about possible life on Europa,” Johnson said. “How thick the ice shell is controls what kind of processes are happening within it, and that is really important for understanding the exchange of material between the surface and the ocean. That is what will help us understand how all kinds of processes happen on Europa—and help us understand the possibility of life.”

For More Information

Planetary Scientists Use Physics and Images of Impact Craters to Gauge Thickness of Ice on Europa
Multiring Basin Formation Constrains Europa’s Ice Shell Thickness

The post What Can Europa’s Surface Tell Us About the Thickness of Its Ice? appeared first on Universe Today.

Categories: Science

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New Scientist Feed - Thu, 03/21/2024 - 2:30pm
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One in Twelve Stars Ate a Planet

Universe Today Feed - Thu, 03/21/2024 - 1:35pm

That stars can eat planets is axiomatic. If a small enough planet gets too close to a large enough star, the planet loses. Its fate is sealed.

New research examines how many stars eat planets. Their conclusion? One in twelve stars has consumed at least one planet.

The evidence comes from co-natal stars, which aren’t necessarily binary stars. Since these stars form from the same molecular cloud, they should have the same ingredients. Their metallicity should be nearly identical.

But for about one in twelve stars, there are clear differences.

The new research is titled “At least one in a dozen stars shows evidence of planetary ingestion,” and it’s published in the journal Nature. The lead author is Fan Liu, an ASTRO 3D Research Fellow in the School of Physics and Astronomy at Monash University, Melbourne, Australia.

“Astronomers used to believe that these kinds of events were not possible.”

Yuan-Sen Ting, co-author, ASTRO 3D researcher from the Australian National University

“Stellar chemical compositions can be altered by ingestion of planetary material and/or planet formation, which removes refractory material from the protostellar disk,” Liu and his colleagues write in their paper. “These ‘planet signatures’ appear as correlations between elemental abundance differences and the dust condensation temperature.”

The authors explain that these signatures are elusive. The key to finding them is to locate co-natal stars, stars that were born together and are still moving together through space.

“We looked at twin stars travelling together. They are born of the same molecular clouds and so should be identical,” said lead author Liu.

The researchers started by using the extreme accuracy of the ESA’s Gaia spacecraft. Gaia’s data allowed the researchers to identify 125 co-moving pairs of stars. Of those, 34 were considered too widely separated but were still used as a control group. The researchers then examined the remaining 91 pairs spectroscopically to determine their chemistry. They used powerful telescopes to gather this data: the Magellan Telescope, the Very Large Telescope, and the Keck Telescope. The large amount of accurate data generated by these ‘scopes allowed the researchers to detect chemical differences and made the findings possible.

“Thanks to this very high precision analysis, we can see chemical differences between the twins,” said Liu. “This provides very strong evidence that one of the stars has swallowed planets or planetary material and changed its composition.”

Liu points out that their findings don’t include stars like red giants that expand when they leave the main sequence and consume nearby planets. “This is different from previous studies where late-stage stars can engulf nearby planets when the star becomes a very giant ball,” Dr. Liu said.

This figure from the study illustrates some of the team’s findings. The top panel shows the different chemical abundances of some chemicals between one pair of co-natal stars. The bottom panel shows the same in percentage differences. Image Credit: Liu et al. 2024.

These results required some detailed analysis. When determining the metallicity of the co-natal stars and how planetary material could explain the different metallicities, the researchers had to account for atomic diffusion. Atomic diffusion can transport different chemicals around in stars, which can change how abundant different chemicals can appear to be. Stars from the same cluster, and co-natal stars, can show different abundances even though they’re the same overall.

However, atomic diffusion leaves a different chemical fingerprint, and the researchers were able to determine how atomic diffusion affects apparent abundance versus how the engulfment of planetary material affects it.

There’s a lot of specific scientific information in this figure from the study. But the primary takeaway is that the abundance of each chemical element in this pair of co-natal stars more closely matches a planet engulfment model (blue dashed line) than atomic diffusion (pink dashed line.) Image Credit: Liu et al. 2024

The results show that some co-natal stars have different metallicity, so some of them have absorbed planetary material. But the researchers point out that some of the results may not come from planetary engulfment. It’s possible that in some of these pairs, one star absorbed material from its protoplanetary disk, which would also change its metallicity.

“It’s complicated. The ingestion of the whole planet is our favoured scenario, but of course, we can also not rule out that these stars have ingested a lot of material from a protoplanetary disk,” he says.

Showing that stars can absorb planets puts another wrinkle into our understanding of stars and their planetary systems. Engulfment doesn’t happen a lot, according to these results, but the fact that it does is intriguing. It leads to questions. How and why does it happen? What situations lead to this engulfment? How does it affect the exoplanet population, and could it affect potential habitability somehow? Engulfment leaves its mark on the star; how does it affect the planetary system?

“Astronomers used to believe that these kinds of events were not possible, said study co-author Yuan-Sen Ting, ASTRO 3D researcher from the Australian National University. “But from the observations in our study, we can see that, while the occurrence is not high, it is actually possible. This opens a new window for planet evolution theorists to study.”

The post One in Twelve Stars Ate a Planet appeared first on Universe Today.

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