Category: Sciency Words

Sciency Words: Null Hypothesis

~ J.S. Pailly ~ 9 Comments

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we look at the meaning and origins of scientific terms.  Today on Sciency Words, we’re talking about:

THE NULL HYPOTHESIS

Whenever there’s a big scientific discovery in the news, my first question is always: should I take this seriously?  The answer is usually no.  The popular press may say one thing, but when you dig into the actual science, you often find the facts do not support the hype.

So when I started reading about a second possible planet in the Proxima Centauri system, I wanted to know: should I take this seriously?  In this article from Scientific American, the astronomers who discovered this possible planet are quoted as saying:

Since the very first time we saw this [potential planetary] signal, we tried to be its worst enemy.

The astronomers are then quoted saying:

We tried different tools to prove ourselves wrong, but failed.  However, we have to keep the doors open to all possible doubt and skepticism.

For me, this is the most reassuring thing any scientist could say.  Too often in popular culture, scientists are portrayed a certain way.

For a multitude of reasons, this is not a real scientist.

But no, good scientists are not out to prove to the world that they’re right.  They’re trying as hard as possible to prove to themselves that they’re wrong.  Which brings me to the null hypothesis.

According to the Oxford English Dictionary and other sources (like this one), the term “null hypothesis” can be traced back to British statistician Ronald Fisher.  Fisher first wrote about the null hypothesis in 1935, in a book titled The Design of Experiments.

As a way of introducing the concept, Fisher tells us the story of a woman who claimed to have an oddly specific talent.

A lady declares that by tasting a cup of tea made with milk she can discriminate whether the milk or the tea infusion was first added to the cup.

The Design of Experiments, by Ronald Fisher

Fisher then describes an experiment to test this woman’s claim.  She’s given eight cups of tea, four with the milk added first, and four with the milk added afterward.

In the context of this experiment, the null hypothesis predicts that the woman will not be able to tell which tea is which—she’s only guessing.  Or to put that in sciencier language, the null hypothesis asserts that there will be no statistically significant relationship between the way this woman’s tea was prepared and the way she believes her tea was prepared. As Fisher explains:

[…] it should be noted that the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation.  Every experiment may be said to exist only in order to give the facts a chance of disproving the null hypothesis.

The Design of Experiments, by Ronald Fisher

A null hypothesis is usually paired with an “alternative hypothesis,” which asserts that a statistically significant relationship does exist.  In Fisher’s tea tasting example, the alternative hypothesis would be that the woman really can tell which tea is which.  You can never really prove that either the null hypothesis or the alternative hypothesis is true, but a well designed experiment should be able to prove that one hypothesis or the other is false.

Going back to that possible planet in the Proxima Centauri system, the article from Scientific American does not explicitly mention the null hypothesis; however, the spirit of the null hypothesis is clearly in play.  Astronomers are trying their best to prove that that planet does not exist, and so far they can’t do it.  And that’s enough to convince me that I should take this new planet seriously (at least for now).

Next time on Planet Pailly, we’ll find out what this not-yet-disproven planet might look like.

Sciency Words: Time’s Arrow

~ J.S. Pailly ~ 2 Comments

Hello, friends, and welcome back to Sciency Words!  Each week, we take a closer look at the definition and etymology of a science or science-related term.  Today’s Sciency Word is:

TIME’S ARROW

Which way is time going?  Prior to the 1890’s, no one would have asked such a silly question.  Time is time.  Everything about time is self-evident.  Why would anyone question it?

But then in 1895, H.G. Wells introduced the concept of time travel to the readers of adventure fiction.  And then in 1915, Albert Einstein started treating time as a variable, rather than a constant, as part of his general theory of relativity.  In his book Time Travel: A History, science historian James Gleick explains:

Millennia had gone by without scientists needing special shorthand like “time’s arrow” to state the obvious—the great thing about time is that it goes on.  Now, however, it was no longer obvious.  Physicists were writing laws of nature in a way that made time directionless, a mere change of sign separating +t from –t.

British astronomer Sir Arthur Eddington gets credit for introducing the “arrow of time” as a conceptual metaphor.  Eddington’s arrow points from the past toward the future.  Unless it doesn’t.  Depending on what sort of physics problem you’re trying to solve (or what sort of Sci-Fi story you’re trying to tell), it may be more convenient to imagine time’s arrow pointing from the future toward the past.

In 1927, in a series of lectures at the University of Edinburgh, and then later in a book titled The Nature of the Physical World, Eddington made three key points about time’s arrow, which I’ll paraphrase as:

  1. Gosh, time’s arrow sure does seem real to us humans.
  2. And common sense reasoning insists that time’s arrow must always point in the same direction.
  3. But when you do the math, you’ll find that none of the laws of physics actually require time’s arrow to exist, except one.

That one exception is the second law of thermodynamics, which tells us that the entropy of a closed thermodynamic system will inevitably increase with the passage of time.  So time’s arrow must always point in the direction of increasing entropy.

Of course a lot of people remain skeptical about time travel.  The Time Machine by H.G. Wells is a fine piece of fiction.  As for general relativity, treating time as a variable (rather than a constant) might help make the math work, but that doesn’t necessarily mean variable time is a real phenomenon.

Still, thanks in larger part to Arthur Eddington and his arrow metaphors, the question “which way is time going?” no longer sounds like total nonsense.

Next time on Planet Pailly: have we discovered a second planet orbiting Proxima Centauri?

Sciency Words: Somaforming

~ J.S. Pailly ~ 11 Comments

Hello, friends, and welcome once again to Sciency Words.  Each week, we take a closer look at some new and interesting scientific term so we can expand our scientific vocabularies together.  This week’s Sciency Word is:

SOMAFORMING

I’d like to begin this post with a quote.  This comes from the 2019 Sci-Fi novella To Be Taught, If Fortunate by Becky Chambers.  As the protagonist of that book explains, we humans are a remarkably versatile species, able to adapt to pretty much any environment—or at least any environment Earth has to offer.

But take us away from our home planet, and our adaptability vanishes.  Extended spaceflight is hell on the human body.  No longer challenged by gravity, bones and muscles quickly begin to stop spending resources on maintaining mass.  The heart gets lazy in pumping blood.  The eyeball changes shape, causing vision problems and headaches.  Unpleasant as these ailments are, they pale in comparison to the onslaught of radiation that fills the seeming void.

I have rarely seen the dangers of human spaceflight so artfully or so succinctly explained as in this book.

Even before Yuri Gagarin became the first human in space, scientists knew space would be rough on the human body.  They did not know specifically what might go wrong, but they knew there would be trouble.  The obvious solution is to create an environment that is safe and comfortable for human beings.

But as early as 1960, some scientists were considering an alternative solution.  Rather than creating space environments that are suitable for human life, why not modify human life to be suitable for the environment of space?  This was the idea proposed by American research scientists Manfred Clynes and Nathan Kline in their 1960 paper “Cyborgs and Space.”

Clynes and Kline proposed some rather drastic surgical changes to the human body.  They make it sound quite easy.  Just rip out a bunch of internal organs.  Replace those organs with synthetic parts.  Pump the patient/astronaut full of drugs and use hypnosis to suppress any psychological issues that might come up during or after the process.  And now you have a human being who’s ready to go to space!  Or you have a human being who’s dead on the operating room table.  One, or the other!

Clynes and Kline introduced the word “cyborg” to describe the half-human/half-machine person they proposed to create.  What Becky Chambers describes in To Be Taught, If Fortunate sounds a little bit safer and a lot less dehumanizing.  And Chambers introduces a new term to describe the transformation her characters undergo: somaforming.  The word is created by analogy with the word terraforming, with the Greek root word “terra” (Earth) being replaced with the Greek root word “soma” (body).

As the protagonist of To Be Taught, If Fortunate explains it, human space explorers come as guests, not conquerers.  The age of colonialism is long behind us. And being good guests, we don’t want to demand too much of our hosts or cause our hosts too much trouble.  To quote Chambers’ book once more: “I have no interest in changing other worlds to suit me.  I choose the lighter touch: changing myself to suit them.”

And I think that is a wonderful sentiment!

As far as I can tell, the word somaforming has not yet been picked up by the scientific community.  But plenty of words from science fiction have been adopted by scientists.  I have a suspicion that this is going to be one of those words.

Next time on Planet Pailly: Oh no!  I made a mistake in an old blog post, and I need to issue a retraction!

Sciency Words: The Yarkovsky Effect

~ J.S. Pailly ~ Leave a comment

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about those weird and wonderful words scientists use.  Today on Sciency Words, we’re talking about:

THE YARKOVSKY EFFECT

Have you ever tried to count all the stars in the night sky?  Well, that might be an easier job than finding and tracking all the asteroids that keep whizzing by our planet.  Part of the problem is due to something called the Yarkovsky Effect.

Ivan Yarkovsky was a Polish engineer working in Russia.  He was also a huge science enthusiast.  If Yarkovsky were alive today, I imagine he’d be writing a blog about all the cool sciency research he was doing in his free time.

But it was the late 19th/early 20th Century.  Blogging wasn’t an option, so instead Yarkovsky wrote pamphlets about science, which he circulated among his science enthusiast friends. And almost fifty years after Yarkovsky’s death, an Estonian astronomer by the name of Ernst Öpik would remember reading one of those pamphlets.

Imagine an asteroid orbiting the Sun.  Sunlight causes this asteroid’s surface to get hot.  Then, as the asteroid rotates, that heat energy radiates off into space.  Would this radiating heat produce any thrust?  Would there be enough thrust to push an asteroid off its orbital trajectory?

Öpik thought so, and in 1951 he wrote this paper introducing the idea to the broader scientific community.  Today’s Sciency Words post would probably have been about the “Öpik Effect,” except Ernst Öpik was kind enough to give credit to the obscure blogger pamphlet writer who originally came up with the concept.  Thus we have the Yarkovsky Effect.

And in 2003, radar observations of the asteroid 6489 Golevka confirmed that the Yarkovsky Effect is real!  The asteroid had wandered 15 km away from its original course!

Around the same time, a copy of Ivan Yarkovsky’s original pamphlet was found in Poland.  As described in this article, it seems Yarkovsky was working on the basis of some faulty premises and a few rather unscientific assumptions.  He more or less stumbled upon the right idea by accident (but let’s not dwell on that part of the story).

Next time on Planet Pailly, no one’s going to name a scientific theory after me, but maybe there’s another sciency honor I can aspire to.

Sciency Words: Solar Wind

~ J.S. Pailly ~ Leave a comment

Hello, friends, and welcome to another episode of Sciency Words.  Each week, we take a closer look at some science or science-related term so we can expand our scientific vocabularies together!  Today on Sciency Words, we’re talking about:

THE SOLAR WIND

The stars twinkle in our sky because Earth’s atmosphere scatters starlight.  The Sun has an atmosphere too, so it shouldn’t surprise you to learn that when astronomers observe stars that happen to be near the Sun (as viewed from Earth), they can see that the Sun’s atmosphere also scatters starlight.

What might surprise you—and what did surprise astronomers in the 1950’s—is that this scattering effect can extend very, very far into the space around the Sun.  The Sun’s atmosphere must be huge!  As reported in this 1959 article from Scientific American, the Sun’s atmosphere might be so big that it encompasses Earth!

Pursuing this and other lines of evidence (such as the apparent correlation between flare activity on the Sun and aurorae here on Earth, as well as apparent 11 year fluctuations in cosmic radiation levels), American astrophysicist Eugene Parker wrote this paper in 1958, introducing a concept now known as the solar wind.

As you might imagine, the Sun’s atmosphere is hot.  Absurdly hot.  Remember that temperature is really just a measure of the average velocity of atoms, and you’ll soon realize (as Parker did) that atoms in the Sun’s atmosphere must have enough velocity to escape the Sun’s gravity.  And since those atoms would also be ionized, these streams of ionized particles coming from the Sun would serve as extensions of the Sun’s magnetic field.

The term solar wind doesn’t appear in that 1958 paper.  Parker first introduces that term in this 1959 paper, in which he defends his idea and responds to critiques from other astrophysicists.  As Parker explains:

In view of the simple hydrodynamic origin of the expansion, it seems appropriate to term the stream a solar wind.

Also in 1959, the Soviet Union’s Luna 1 space probe gathered the first empirical evidence that the solar wind really does exist, leading to confirmation that Eugene Parker’s solar wind hypothesis was correct.

And today, a NASA spacecraft named in Parker’s honor is spiraling closer and closer to the Sun, gathering more data about the solar wind and other mysterious phenomena associated with the Sun.

Next time on Planet Pailly, now that we’ve talked about the solar wind in our own Solar System, we’ll check out the space weather forecast for the solar system next door.

Sciency Words: Colony

~ J.S. Pailly ~ 11 Comments

Hello, friends!  Welcome to another episode of Sciency Words.  Normally on Sciency Words, we talk about those strange words scientists use, but today we’re going to talk about a word scientists—or at least some scientists—would prefer to stop using.  And that word is:

COLONY

Mars is so eager for humans to come visit and maybe even stay permanently.  And plenty of humans are eager to do just that!  We’ll bring life to Mars.  Not only that, we’ll bring civilization and culture.  One might say it is humanity’s destiny to colonize Mars.

But is this language of “colonization” and “destiny” too evocative of European imperialism?  Some think so, and they would ask that we stop using such colonialist language when we talk about space exploration.

Now I want to be clear about where I’m coming from on this: I try my best to call people by the names and terms they prefer to be called, and if I find out that the language I use offends somebody, I’ll do may best to change.  Some would accuse me of being too P.C., but I think it’s just good manners.

And I have found that if you make an effort to be respectful and accommodating to others, others will make an effort to be respectful and accommodating to you, and in general they’ll be more willing to forgive you if/when you do slip up and say something unintentionally hurtful.

So a few years back, when I came across this article from National Geographic, I started reading it with an open mind and a willingness to change.  But by the end of the article, even I felt like this was an example of political correctness run amok.  The word “colony” is offensive.  So are the words “settlement” and “frontier.”  Okay.  What words should I use instead?  Even that National Geographic article seems to concede at one point that we don’t have many workable alternatives to these terms.

But this concern does seem to be coming up more and more.  Plenty of people in the scientific community are shying away from words like colony and colonization.  Bill Nye (the Science Guy) says he avoids the word colony, and this official glossary of SETI terminology warns that “settle” and “colonize” may have certain negative connotations for some people.

So at this point, I’m not sure what to think.  What about you?  Do you think this is much ado about nothing, or should we really start looking for alternatives to words like “colony” or “settlement” in our space exploration vocabularies?

Next time on Planet Pailly… I actually don’t have anything planned yet for my next blog post.  We’ll probably just talk about more space stuff.

Sciency Words: Superhabitable

~ J.S. Pailly ~ 15 Comments

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about the meaning and origin of scientific terms.  Today’s sciency word is:

SUPERHABITABLE

The word “habitable” traces all the way back to ancient Latin.  Think of a residence or dwelling.  Think of tenants and landlords and the act of paying rent.  That’s the sort of thing words like habitabilis, habitator, or habitatio referred to.

Of course when we talk about planets, the meaning of “habitable” and “habitability” is a bit different.  Unless…

In our ongoing search for extraterrestrial life, it’s generally assumed that Earth is typical of habitable planets.  But why should we assume that?

In this 2014 paper, physicists René Heller and John Armstrong claim that Earth is not as perfectly suited for life as it seems.  In some ways, Earth is kind of a dangerous place to live, and there have been several instances where life on Earth nearly got snuffed out.  Heller and Armstrong then go on to argue that other worlds may “offer more benign environments to life than Earth does.”

If we insist on calling Earth “habitable,” then Heller and Armstrong propose calling those other worlds “superhabitable.”  Though really, if we’d stop being so geocentric and anthropocentric in our terminology, it is the “superhabitable” planets that should set the standard for habitability, and Earth would be better described as “marginally habitable.”

So what sort of planet would offer a more benign environment for life than Earth does?  Well, according to Heller and Armstrong, planets that are two to three times as massive as Earth would do nicely.  More massive planets will remain geologically active for longer, and they’ll have stronger magnetic fields to protect life from solar and cosmic radiation.  Shallower oceans and a thicker atmosphere would help too.

A smaller and cooler star would also be preferable.  A K-type “orange dwarf” would spew out less harmful radiation than our own G-type Sun, and K-type stars last longer.  A whole lot longer.  No need to worry about the day the sun dies if your planet orbits a K-type star!

Personally, I feel like Heller and Armstrong are making a lot of big assumptions in describing their superhabitable planets.  There may be some wishful thinking at work here.  But then again, it’s also a pretty big assumption to assume that Earth is a typical example of a habitable world.  There’s probably some wishful thinking at work there too.

Next time on Planet Pailly, the nearest superhabitable planet could be a lot closer than you think (unless you clicked that link above, in which case you probably know where Heller and Armstrong said the nearest superhabitable planet might be).

Sciency Words: Anophthalmus hitleri

~ J.S. Pailly ~ 11 Comments

Hello, friends!  Today’s post is probably a bad idea!

Sciency Words is a special series here on Planet Pailly where we talk about scientific terminology.  In today’s episode, we’re talking about:

ANOPHTHALMUS HITLERI

If you’re the first person to identify a new species, you get to name it.  That’s the rule.  You do have to double check to make sure nobody else identified your species first, and the name you pick should sound vaguely like Latin.  But otherwise, be creative, have some fun, and name your newly discovered species however you like!

That’s what Austrian entomologist Oskar Scheibel did in 1937.  Scheibel was the first to identify a species of blind, cave-dwelling beetle native to Slovenia, and he decided to name these beetles after one of his greatest heroes: Adolf Hitler.

Anophthalmus hitleri can be translated to mean “the blind one of Hitler”—a name which seems symbolically appropriate, in a way.  They’re now an endangered species.  Apparently a lot of Neo-Nazis really want a Hitler beetle for their Nazi memorabilia collections, so much so that Anophthalmus hitleri is being driven to extinction by poachers—a fact which also seems symbolically appropriate, in a way.

But this post isn’t really about Hitler or Neo-Nazism.  Rather, I’m bringing this up because the example of Anophthalmus hitleri helps illustrate an important point about scientific terminology: once a name has been established in the scientific lexicon—even if it’s a really awful name like Anophthalmus hitleri—it’s really hard to change it.

Scientists like being able to review prior research about a given topic.  If scientists were constantly renaming things, that would make finding all that prior research rather difficult.  This is especially true when it comes to species names.  There are an absolutely ridiculous number of species out there, and keeping track of them all is hard enough as it is.

The International Commission of Zoological Nomenclature is currently in charge of the rules for naming animal species.  And the rules are, basically, what I said before: if you’re the first to identify a new species, you get to name it.

The only way a species name can be changed is if some new information comes to light, or some new discovery is made, revealing that you made some sort of mistake.  Maybe you weren’t really the first person to identify that species, or maybe you assigned your newly discovered species to the wrong family or genus.  But Oskar Scheibel doesn’t seem to have made any mistakes like that, and so Anophthalmus hitleri is stuck with the name it’s got.

Next time on Planet Pailly, I like to think I’m pretty smart, but maybe I’m not as smart as I think.

Sciency Words: Barycenter

~ J.S. Pailly ~ 11 Comments

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about those big, complicated words scientists use.  Today’s Sciency Word is:

BARYCENTER

Excuse me, but I’m going to do that “um, actually” thing that people who think they’re really smart like to do.  Now you may think the Earth orbits around the Sun.  Um, actually… the Earth and Sun both orbit something called the barycenter.

The word barycenter comes from two Greek words meaning “heavy” and “center,” and it refers to the common center of mass for two or more celestial bodies.  Based on sources I found via Google Ngrams, the term started appearing frequently in astronomical journals during the early 20th Century, and it may have been in use as early as the 1880’s.

Let’s say you have two celestial bodies.  One is really massive, the other is much less massive.  In that case, the barycenter will probably be located somewhere inside the more massive object.  This is the case for the Earth and her Moon.  Based on numbers I got from Wikipedia, the Earth-Moon barycenter is about 1000 miles (1700 km) beneath Earth’s surface.  Or to measure that a different way, the barycenter is about 3000 miles (4600 km) away from the center of the Earth.

Now let’s say you have two celestial bodies of roughly equal mass.  In that case, the barycenter will be located somewhere between them.  Something like this has happened with Pluto and his giant moon, Charon.  Once more using numbers from Wikipedia, it looks like the Pluto-Charon barycenter is about 500 miles (960 km) ABOVE the surface of Pluto.

As for the Earth-Sun barycenter, it’s located deep inside the Sun.  So if you say Earth orbits the Sun, you’re not too far from the truth.  But of course Earth is not the only planet in the Solar System, and when you consider the Solar System as a whole, you’ll find the Sun wibbles and wobbles about in weird, loopy patterns.  As you can see in the highly technical diagram below, the Sun wibbles and wobbles so much it can wobble into a totally new position in just a few years.

Click here for an actual diagram of the Sun’s movement relative to the Solar System’s barycenter.

As explained in this paper, this is mainly due to the gravitational influences of Jupiter and Saturn. Over longer time scales (centuries rather than decades), the subtler influences of Uranus and Neptune also have a noticeable effect.

So the next time someone tells you the Earth orbits the Sun, you can do the “um, actually” thing and explain what a barycenter is.  Trust me, it’s a great way to sound smart and make lots of new friends!

Next time on Planet Pailly, what did people in 1962 think we’d find on other planets?

Sciency Words: Metal

~ J.S. Pailly ~ 13 Comments

Hello, friends!  Welcome to another episode of Sciency Words, a special series here on Planet Pailly that’s all about those weird words scientists use.  Today on Sciency Words, we’re talking about:

METAL

Yes, scientists use some very strange words.  You know the kind of words I mean.  Words that are hard to pronounce.  Words with definitions that only make sense if you understand differential calculus.  But you know what’s even weirder?  When scientists take words you already know and redefine them.  That’s what astronomers and astrophysicists have done to the word “metal.”

Approximately 75% of the matter in the universe is hydrogen.  24% of it is helium.  And the remaining 1%?  Ask an astrophysicist, and they’ll tell you the remaining 1% is all “metal.”  If that seems weird to you, don’t worry.  All the other scientists think it’s weird too.

For years now, I’ve been trying to figure out how this started.  Who gets credit (or blame) for first messing up the definition of metal?

I don’t know, but I do have a pet theory.  Perhaps certain chemical elements (like nickel or iron) are easier to detect in outer space than others.  And if you’re trying to study that 1% of the material universe that isn’t hydrogen or helium, perhaps those easier-to-detect elements (which happen to be metals) serve as a convenient proxy for everything else—including nonmetals like nitrogen, carbon, and oxygen.

According to the Oxford English Dictionary Online, the earliest documented usage of either “metal” or “metallicity” (in the astronomy sense of those words) is this 1969 paper on the molecular composition of stars.  Now I won’t pretend to have read the whole paper (it’s over 60 pages long), but based on what I did read, I can say this much: this cannot be the true first usage of the word metal (in the astronomy sense).

At one point, the authors, two astronomers from U.C. Berkley, categorize nitrogen as a metal.  No explanation is offered.  Clearly the authors expect their readers (i.e. other astronomers) to understand why nitrogen would be considered a metal, which suggests to me that most astronomers in 1969 already understood “metal” to mean “matter that isn’t hydrogen or helium.”

However, I can also say this: I think this paper supports my pet theory.  The paper describes a new technique for determining the molecular composition of stars.  In explaining this new technique, the authors focus on the spectroscopic signatures of three specific elements: sodium, magnesium, and calcium.  Those three elements are then used as a proxy for all the other non-hydrogen and non-helium elements that might be found inside a star.

Sodium, magnesium, and calcium are all—wait, let me double check the periodic table—yes, all three of those elements lie on the metal side of the metalloid line.  And thus through a process linguists call semantic generalization, the word metal is generalized to mean something more than it originally meant.

Next time on Planet Pailly, someone really wanted to pick a fight with me about life on Mars.