Tag Archives: science

Mathematical Proof that Aliens Do Not Exist (Sorry to Burst your Bubble)

Every now and then random people in the world go bat-guana crazy about something, whether it’s about a Big Foot sighting, or believing that a trust-fund billionaire troll-bot will govern for anyone other than other billionaires, or evidence of extraterrestrials. This latter went big in 2016, moving from cow-probing theory-spinning abductees to legitimate astronomers and physicists who tried really, really hard not to sound like they were talking about E.T.

However they tried to dress it up, it was ridiculous. A star, KIC 8462852 (now known as Tabby’s Star), was showing behaviour they didn’t recognise, and the cry of “ALIENS” reverberated around the internet. Sound like a familiar argument?

In fact, the probability of contact with extraterrestrial intelligence is so tiny that there is literally no evidence compelling enough to refute the maths. I explain this here.

The Latest Extinction Event Began Thousands of Years Ago

Some researchers in Denmark have released a map of what global mammalian megafauna distribution would be like if humans hadn’t existed. Spoiler Alert: There would be a lot more big mammals everywhere. I don’t think this is a surprise to anyone who has paid any attention to species that have gone extinct but which human ancestors dealt with (I think the problem is that everyone conflates “extinct” into one period, from the dinosaurs to the dodo bird), but this is the first time that I know of that it has been quantified and displayed in an easy-to-understand graphic. Here’s the map:
largemammalsdistribution
I’ve often argued that the reason there are still so many large mammals in Africa is because they evolved with humans, and everywhere else they evolved without humans – invasive species tend to mess things up. The authors agree with me, and go further to say that many of our ideas about diversity are wrong. For example:

Today, there is a particularly large number of mammal species in mountainous areas. This is often interpreted as a consequence of environmental variation, where different species have evolved in deep valleys and high mountains. According to the new study, however, this trend is much weaker when the natural patterns are considered.

“The current high level of biodiversity in mountainous areas is partly due to the fact that the mountains have acted as a refuge for species in relation to hunting and habitat destruction, rather than being a purely natural pattern. An example in Europe is the brown bear, which now virtually only live in mountainous regions because it has been exterminated from the more accessible and most often more densely populated lowland areas,” explains Soren Faurby.

I found the press release through IFLS, and Josh Davis writes at the bottom:

The study does, however, presume that the changing climate at the end of the Pleistocene was not sufficient to kill the large mammals off on its own, and that it was man’s influence that delivered the death blow. This area of research is hotly debated and contested, with arguments flying back and forth as to the real reason the world’s large mammals died out. It’s generally thought likely to be a combination of climate change and hunting, but it’s impossible to say whether or not all species of mammal would have been able to adapt sufficiently to a changing environment and survive to present.

I can’t help but think arguments against human causes are simply trying to avoid guilt. Let’s look at Australia: The continent had a vast diversity of mammalian megafauna for tens of millions of years, megafauna that survived ice ages and warm times, and – most relevant – several glaciation events within the current ice age. Along come humans, and during the very next glaciation event that happens many, many species become extinct. The significant difference was the introduction of humans. Sure, it’s “impossible” to say whether all species of mammals would have been able to adapt, but it’s a pretty safe bet that most of them would have, because they had before.

Power Doesn’t Corrupt, It Empowers

I’ve often been leery of psychological experiments which come out with statements like “people in this situation behave this way”, as if the results weren’t averaged over everyone in the experiment…as if individuals in the experiment didn’t respond differently to the situation. Scientific American has a blog post about the Stanford Prison Experiment, which famously showed that people who are given power and no oversight become abusive sadists. He puts a convincing argument that “Yes, power corrupts. But power does not corrupt everyone equally”. In fact, people inclined to try and improve society become more generous when given power.

The most interesting part for me was in the footnote, about a British experiment that tried to replicate the Stanford one but failed because it had an ethics committee.

There was even some uncertainty about roles. At least in the beginning, prisoners were told that they might be able to become guards. Research shows that in environments in which authority is unstable, or at least perceived as unstable, being in a position of low power can actually be empowering. As one group of researchers put it, “For low power individuals, power instability is empowering, leading them to act and behave as high power individuals… Having unstable low power leads to feelings of confidence and self-efficacy, especially when low power individuals can gain power by being creative. They may be more confident about their abilities and also perceive that they have the ‘power to change their situation.”

Democracy is one of the ultimate forms of power instability, and such a situation causes low-power individuals to act like high-power individuals, which is really useful because: “Power increases confidence, optimism, risk-taking, sensitivity to internal thoughts and feelings, goal-directed behavior and cognition, and creativity.”

So let’s keep our democracies as democratic as possible, yeah?

PS: One of the problems with science is how few experiments are reproduced, and when they are the results aren’t always great.

Source: NASA

The Irrelevancy of Logical Fallacies in Mathematics

Scientific American is focusing on Einstein in September, it being 100 years since he came up with the general theory of relativity. It briefly describes how he came up with the theory, which makes it a lot easier to understand and is interesting to me because it contains a logical fallacy.

Einstein claimed that the happiest thought in his life was: “If a person falls freely, he will not feel his own weight.” To be honest, this sounds like his personal troubles were causing depressive episodes. However, he noted that if a man was in an enclosed chamber in free fall, he would feel weightless. He would not be able to tell if he was in free fall or if he was floating in zero gravity. Likewise, if the chamber was in zero gravity and a constant force was pulling the chamber up at an accelerated rate he would feel his feet pressed to the floor, and would have no way of telling if he were in a stationary chamber under gravity or was being accelerated in zero gravity.

Einstein dubbed this “the equivalence principle.” The local effects of gravity and of acceleration are equivalent. Therefore, they must be manifestations of the same phenomenon, some cosmic field that accounts for both acceleration and gravity.

This seems to be an invalid argument. It takes the form:

If A, then C.
If B, then C.
Therefore, A = B.

Just because two things have the same effect doesn’t mean they are the same thing. For example, saying “if an elephant sat on me I would die, and if a rhinoceros sat on me I would die, therefore an elephant is a rhinoceros” is clearly incorrect.

Of course, this insight of Einstein’s allowed a theory that is very good at explaining the universe that we observe. That could be because it got translated into mathematics, and in mathematical logic it is actually true. If A=C and B=C, then A=B must be true.

This might indicate something very profound about mathematics and its relation to the universe, but I’m not sure what.

Science: Pears Before Booze Prevents Hangovers

Science has been hard at work answering the big questions…and the biggest question facing humanity is: “How can we avoid facing the consequences of our stupid decisions?” The CSIRO has this to say:

What hangover symptoms can pears prevent?
Overall hangover severity, as measured by a 14 item hangover symptom scale, was significantly reduced in the Korean pear group compared to those having a placebo drink, with the most pronounced effect seen on the specific symptom of ‘trouble concentrating’.

The thing I love most about this is that someone got paid to eat pears and drink booze, just to see how bad the hangover was afterwards. This is clearly one of those cases where someone thought “how can I get research funds to get drunk?”, and that brings a little tear of pride to my eye*. If I ever do a science research project, I will research the effectiveness of every hangover cure I can come across, and spend my entire PhD inebriated.
That’s a valid life goal.

*Other examples include studying the local climate effects of wineries on fruit fly pests, so your doctorate requires that you visit every winery in the country; and the effect of different strains of barley on the flavour of the beer it produces, which obviously involves drinking a lot of beer.

The Multicellularity of Alien Life Forms

The latest news out of biology (well, it’s been building for quite a long time) is that the tree of life is very different from how we thought it was. The bit that got me excited?

In the new vision — based on increasingly sophisticated genetic analyses — people and other animals are closer cousins to single-celled choanoflagellates than to other multi­cellular organisms. Giant kelp that grow as wavering undersea forests off the California coast are closer relatives to single­-celled plankton called diatoms than to multicelled red seaweeds or plants.

This is because it obliterates the notion that multicelluarity evolved only once. In fact, Wikipedia claims “complex multicellular organisms evolved only in six eukaryotic groups: animals, fungi, brown algae, red algae, green algae, and land plants. It evolved repeatedly for Chloroplastida (green algae and land plants), once or twice for animals, once for brown algae, three times in the fungi (chytrids, ascomycetes and basidiomycetes) and perhaps several times for slime molds, and red algae.” This is cool because it removes one of the bottlenecks for intelligent life: The chances of life spontaneously evolving are vanishingly small (once that we know of), and the chance of eukaryotic life developing is also vanishingly small (once that we know of). However, where in the past it was thought* that multicellularity evolved only once, now it seems a common, and therefore inevitable, occurrence.

Which means, if we do find extraterrestrial life, it will almost certainly be multicellular in some way.

*At least by me, and it seemed to be the general thought when I went through uni 20 years ago. I don’t know how long scientists dedicated to the field have been aware of this.

For more alien life science, see Life In Cryogenic Conditions.

Are All The Men You’ve Loved Before Living In Your Brain?

The idea that a person can be invaded by other human cells, which then go on to live and probably reproduce in the host body, following their own hidden agenda, is a reasonably disconcerting one. However, we’ve known for a long time this happens, and not just freak accidents like a twin getting absorbed in the womb; fetus cells often cross the placenta and take up residence in their mother’s bodies, and remain there for the life of the mother.

The easiest way to detect this is to look for y-chromosomes in women – if there is one, it’s due to microchimerism, where there are some male cells living in the female body. But now there’s this: Male microchimerism in women without sons: quantitative assessment and correlation with pregnancy history. This study found that one in five women were male microchimeric, which is a huge figure even if it’s skewed by women who had induced abortions (where one in two are male microchimeric).

chimeraWe can infer some things from this. First, total microchimerism is probably double that reported, since there’s no real reason to assume that male cells are better at colonising a mother’s body than female cells, they’re just easier to detect. If we assume there is no greater tendency to abort male fetuses than female fetuses, we can also infer than effectively everyone who had an induced abortion is microchimeric and carries with them the cells of the fetus. This is the sort of creepy detail that can lead to b-grade horror sci-fi stories, but it can also be considered beautiful and romantic: No fetus really dies, it lives on within the mother. There’s also a high chance that any dead child continues to live in the body of its mother. I guess it depends on your point of view.

However, perhaps the most interesting result from the study was that of the women who had only had daughters 8% were male microchimeric, and the nulligravid (never-pregnant women) had a rate of 10% of male microchimerism. There are two ways to look at this. The first:

Sperm is alive. It is living cells. When it is injected into you it swims and attaches and burrows into your flesh. If its in your mouth it swims and climbs into your nasal passages, inner ear, and behind your eyes. Then digs in. It enters your blood stream and collects in your brain and spine. Like something out of a sci-fi movie.

This rather frenzied interpretation is the result of the conclusion stating: “Besides known pregnancies, other possible sources of male microchimerism include unrecognized spontaneous abortion, vanished male twin, an older brother transferred by the maternal circulation, or sexual intercourse.” Again, some people may consider it romantic that women carry around the living cells of the men they sleep with, and it gives a whole new meaning to the phrase “he got under my skin”. However, I think it unlikely that sperm manage to invade and survive in a woman’s body considering that: a) It’s a very hostile environment for sperm, and b) If the sperm don’t join with an egg cell they die in a few days. They can’t reproduce on their own because they only have one set of chromosomes.

So the second point of view is that all of those “freak accidents” that cause microchimerism that we think are so rare, like a vanished twin or maternal circulation, are actually far more common than we thought. Not just in women, either – a lot of these can apply to men too.

If you’re sitting around a campfire late at night this might raise other questions as well, such as: What does it mean for how we view an organism? Does it change our sense of self? Does it count as “consuming human flesh”?

(Here’s a story about Evil Sperm)

Non-Polar Membranes

Life In Cryogenic Conditions

A pretty interesting resource for science fiction writers just popped up. It considers the evolution of life in extremely cold places, such as Saturn’s moon Titan where the surface temperature is about –179 Celsius, specifically what sort of membranes might be available for life to use. In addition to the extremely low temperature which would insta-freeze most molecules into solids, at that temperature the liquid oceans are composed of methane, which is non-polar… so that has to be taken into account.

The researchers at Cornell University ran a computer model with the compounds that we’ve detected in Titan’s atmosphere, and come up with acrylonitrile as the best candidate to form membranes in those conditions. They’ve termed these membranes azotosomes (as opposed to the liposomes that make up our cells) and have calculated they have pretty much the same characteristics as liposomes. Acrylonitrile has three carbons, three hydrogens and a nitrogen, which makes the membrane a lot thinner than liposomes, but that’s pretty much a requirement for working at such a low temperature. The other main difference between azotosomes and liposomes is that in terrestrial liposomes the oxygen-powered polar head is on the outside, interacting with water molecules, while the non-polar tails create the inner barrier, while azotosomes have the nitrogen-powered polar head on the inside of the membrane, and the short non-polar carbon tails interacting with the liquid methane. This can be seen in the image above, where A is a lipid membrane and B the hypothesised acrylonitrile one.

This is not proof of life on Titan, of course, but it’s evidence that at least one of the necessary components for life – compartmentalisation – is possible on that moon. The other components of metabolism are still necessary, and I wonder how they’d run at that temperature; would reactions necessarily be far slower than those of life on Earth, and if so how would that affect the organisms? How would that affect a sentient organism?

Scientific American Article
James Stevenson, Jonathan Lunine, Paulette Clancy: Membrane alternatives in worlds without oxygen: Creation of an azotosome, Science Advances Vol 1, No 1.

The Free Market in the Bacterial World

Bacteria can exchange vital nutrients with other bacteria, effectively distributing metabolic functions within the microbial communities. This is one of things that was supposed to differentiate unicellular life from multicellular life…

As reported in io9:

Just over a year ago, the lab of Christian Kost, based out of the Max Planck Institute for Chemical Ecology in Jena, Germany, showed that two strains of bacteria, genetically engineered to lack one nutrient and overproduce another, could support one another in the same flask if their deficiencies and surpluses were complementary. On their own, either strain would not survive. (The nutrients were the two amino acids, histidine and tryptophan).

These bacteria grew 20 percent faster than strains that didn’t require the exchange of nutrients, indicating a benefit to specialisation (of the kind that would be familiar to any beginner economics student). Anyway, the really interesting news here is that the nutrients aren’t excreted into the media and absorbed by other bacteria; a bacterium that lacks one of the nutrients will actively seek out other bacteria that have the nutrient and then hook up a tube to them to exchange nutrients. This could be mutualistic or parasitic, but either way it’s pretty high-level behaviour for a single celled organism.

Of course, it has been known that bacteria exchange DNA and RNA through this method for quite a few years and its pretty clear this is happening in the wild as well as in the lab – and between bacteria of different species.

This has significant implications for the way we think bacteria evolve (although I don’t think many microbiologists will find this result particularly revolutionary, more another piece in the puzzle). It’s not just that bacteria don’t rely on mutations to adapt, they can pass genes between each other, now it turns out they might outsource some metabolic pathways. When a particular compound becomes scarce and they can’t synthesise it, they just seek out other bacteria that can.

There’s still some questions, of course, including how the bacterium can tell which other bacterium to attach to, and whether the other has to be “willing”. However, the idea of bacteria as individual organisms swimming alone in their environment in competition with everything they come across should be dead in your head by now.

(image source: Electron microscopy image of E. coli using nanotubes to survive off of a continuous trade of amino acids with other bacteria. Martin Westermann, University Hospital of the University of Jena.)