Category: Sciency Words

Sciency Words: A to Z Challenge

~ J.S. Pailly ~ 4 Comments

I’ve wanted to do this for a while now, but every year I chicken out. It’s a lot of writing. That by itself is intimidating. For me, it’ll be a lot of research and a lot of drawing as well, all packed into twenty-six days.

I nearly chickened out again, but this year I’m finally doing it. I’m doing the A to Z Challenge. Throughout the month of April, I’ll be posting every day (excluding Sundays), with each post proceeding through the alphabet letter by letter. And my theme will be Sciency Words (obviously).

For those of you who might be new to my blog, Sciency Words is a weekly series where we look at some interesting new science or science related term so we can all expand our scientific vocabularies together.

I’m going to use the A to Z Challenge as an opportunity to cover some terminology that I’ve never really had a good reason to cover before. I’ll also revisit a few terms that I’d like to say more about. And while we’re at it, we might touch on a few controversies surrounding the definitions of certain terms.

Don’t worry, Pluto. We’ll get to you.

So tune in beginning tomorrow for the Sciency Words: A to Z Challenge. We’ll be starting with acetic acid.

A to Z Challenge Links

Main Website: www.a-to-zchallenge.com

Facebook Page: www.facebook.com/atozchallenge

Twitter: @AprilAtoZ

Twitter Hashtag: #atozchallenge

Sciency Words: The Fermi Paradox

~ J.S. Pailly ~ 9 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

THE FERMI PARADOX

Enrico Fermi was an Italian physicist, one of the many great scientists who immigrated to the United States right before the outbreak of World War II. He is most noted for creating the first nuclear reactor and the role he played in the development of the atomic bomb.

But that’s not what we’re going to talk about today. Today we’re talking about something Fermi said half-jokingly over lunch.

Where Is Everybody?

Based on some historical detective work, we can say this probably happened in the summer of 1950. Fermi was visiting the Los Alamos National Laboratory. He and a few colleagues were having a lunchtime conversation about flying saucers. Apparently there had been an amusing cartoon about little green men in a recent edition of the New Yorker.

The conversation got serious (sort of) when Fermi suddenly asked: “but where is everybody?” Everyone at the table laughed, but Fermi’s question and the not-entirely-serious discussion that followed would become the basis of what we now call the Fermi paradox.

As a matter of statistics and probability, it seems like advanced alien civilizations should be out there somewhere. There are over 100 billion stars in our galaxy. Many (if not most) of these stars have planets orbiting them. Some of these planets must surely support life, and in at least a few cases intelligent life—life capable of developing interstellar travel.

Even without faster-than-light technology, one or more of these space-faring civilizations could conceivably spread across the whole galaxy in just a few million years. The galaxy is far, far older than that. There’s been plenty of time for the aliens to do it. So where is everybody? Shouldn’t we have heard from somebody by now?

Or so Fermi argued over his club sandwich (or whatever he was eating) in a half-serious conversation about flying saucers. Of course there are plenty of objections to Fermi’s line of reasoning here, but I’m not going to weigh in on that. Not today. I’m saving my opinion for Monday’s post.

Sciency Words: Ultra-Cool Dwarf Star

~ J.S. Pailly ~ 2 Comments

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

ULTRA-COOL DWARF STAR

At some point, I want to profile each of the planets in the TRAPPIST-1 system one by one for my Exoplanet Explorer series. But it’s too early for that. Right now, we don’t know much about these planets except that they’re there.

But I can say something about TRAPPIST-1 itself. It’s a type of star called an ultra-cool dwarf star.

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Apparently TRAPPIST-1 has just barely enough mass to cause hydrogen fusion in its core. That means that for a star, it doesn’t produce a whole lot of energy, and thus its temperature is relatively low. Based on my rough math and statistics I got from Wikipedia, it looks like TRAPPIST-1 is less than half the temperature of our Sun.

This is one of the things that makes TRAPPIST-1 so interesting to me, and why it’s really starting to capture my imagination. It’s not just about all those Earth-like planets. The star itself helps set a lower limit for just how small and cold stars can be.

Sciency Words: Earth Similarity Index

~ J.S. Pailly ~ 5 Comments

Sciency Words BIO copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

EARTH SIMILARITY INDEX

As I’m sure you’ve heard by now, astronomers have discovered seven planets orbiting a nearby star called TRAPPIST-1. Even more exciting, most or all of these new worlds are being described as Earth-like planets. But what does that actually mean?

You’d be surprised by how many “Earth-like” planets/moons we have right here in our own Solar System.

Ag16 Earth-like Worlds
From left to right: Venus, Earth, Mars, and Titan (Saturn’s largest moon).

Earth-like is a rather vaguely defined term. So in 2011, a paper published in the journal Astrobiology attempted to establish an official mathematical system for calculating just how Earth-like an exoplanet is. It’s called the Earth Similarity Index or E.S.I.

Basically, the E.S.I. takes certain characteristics of a planet that can be quantified—such as a planet’s mass, radius, temperature, etc—and compares them to Earth’s. An E.S.I. score of zero indicates a planet that has absolutely nothing in common with Earth, while an E.S.I. of one means the planet is an exact match for Earth… at least with regard to the characteristics being measured and included in our calculations.

Of course even a planet with an E.S.I. of one is not necessarily habitable, so the same Astrobiology paper also proposes a Potential Habitability Index or P.H.I. But that, I think, is a Sciency Word for another day.

P.S.: If you want to dive into the math behind the E.S.I., click here.

Sciency Words: Light Curve

~ J.S. Pailly ~ 5 Comments

It’s been almost a week since I arrived at KIC 8462852, better known as Tabby’s Star, and discovered that the aliens really are building a megastructure. I still have a lot of questions, but the aliens aren’t giving me a lot of answers, and I think it’s time I moved on.

Which brings me to today’s edition of Sciency Words.

Sciency Words MATH

Each week, we take a closer look at some science or science-related term to help us all expand our scientific vocabularies together. Today’s term is:

LIGHT CURVE

We met astronomer Bradley Schaefer in Wednesday’s post. Writing for Scientific American, he defines a light curve as “a measure of brightness as a function of time.”

So the light curve of a star with a constant brightness would be a straight line. If you found small, symmetrical dips in that line, that might mean there’s a planet in orbit, especially if the dips appear at regular intervals. Here’s an example of what that looks like, courtesy of NASA.

Other patterns of dips or spikes along a light curve could tell you if you’re looking at a binary star, or a flare star, or a variable star… looking at light curves is a great way to study stars.

As for Tabby’s star, its light curve is apparently a straight line most of the time, aside from tiny fluctuations that typically indicate solar flares and/or sunspots. In other words, Tabby’s star looks normal.

And then abruptly, dips appear in the light curve. Asymmetrical dips, as opposed to the symmetrical dips caused by transiting planets. In some cases, the line doesn’t so much dip as plunge downward, and that means… umm… astronomers do not know what that means.

Any serious discussion about Tabby’s Star should really begin with its weird, almost spastic light curve. I’m choosing to end here, however, because the aliens have made it clear that I’m not welcome.

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Now I need to find another megastructure to study, and the best way to do that is to examine the light curves of other stars.

Sciency Words: Tabby’s Star

~ J.S. Pailly ~ 5 Comments

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

TABBY’S STAR

Something’s wrong with a star named KIC 8462852. It flickers. It dims by as much as 22% for no apparent reason. This is an F-type main-sequence star, meaning it’s only a little bit larger than our Sun. F-type stars shouldn’t behave like this.

KIC 8462852 is sometimes called the WTF Star, because of the paper that first described its abnormal fluctuations in brightness. That paper was subtitled “Where’s the Flux?”

The star is also known (and perhaps better known) as Tabby’s Star, in honor of Tabetha Boyajian, the lead author on that paper.

There are several possible explanations for what might be happening to Tabby’s Star, but it’s the least likely explanation that’s gotten the most hype. Could it be aliens? SETI decided to check it out. They didn’t find anything. But still… it could be aliens.

Massive alien starships might be transiting the star, blocking some of its light. Or perhaps there are enormous space stations orbiting the star. Or maybe we’ve caught an advanced alien civilization in the act of building some kind of megastructure (like a Dyson sphere) completely encircling their sun.

Most professional astronomers do not think it’s aliens. Tabetha Boyajian herself doesn’t seem to take the idea seriously and often jokes about the crazy emails she gets from people who do. And to be perfectly clear, I do not take this alien megastructure hypothesis seriously either.

But just to be sure, I’ve decided to hop into my imaginary spaceship and fly out to KIC 8462852, just so I can see for myself what’s really going on. Wish me luck! I’ll let you know what I find next week.

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Sciency Words: Ecotype

~ J.S. Pailly ~ 4 Comments

Sciency Words BIO copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

ECOTYPE

Let’s say you discover two groups of antelope. Both groups are the same species, but one group lives on the east side of a mountain range and the other group lives on the west side.

Again, these antelope are all the same species of antelope. But because of a geographic barrier, the two groups rarely if ever intermix or interbreed. As a result, one group has developed thicker wool than the other, or they have slightly different antler shapes, or there’s some other distinctive characteristic that one group has and the other doesn’t.

When you find distinctly different groups within the same species, the groups are called ecotypes. Typically, this sort of differentiation occurs within a species because ecotypes are living in separate ecological habitats.

I first encountered this term in a recent article in Scientific American. As a science terminology enthusiast, I find this to be an interesting kink in the ongoing debate over how to define the word “species”—but the article I read was about something even more interesting than that.

Orca Ecotypes

If we ever learn to communicate with orcas (killer whales), we should tell them about Shakespeare.

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Orca ecotypes don’t mix, even though there’s nothing stopping them. They’re genetically compatible. Their territories overlap. They encounter each other in the open ocean all the time, but apparently they don’t like to intermingle due to what Scientific America calls “cultural differences.”

We should be careful about anthropomorphizing animal behaviors. When Scientific American says orcas have “cultural differences,” they mean they have different hunting and feeding practices. And also different clicking/whistling patterns for communication.

Actually, that does sound a little bit like orcas have human-like languages, and maybe even a primitive version of human-like culture. And those linguistic and cultural barriers are enough to keep them apart. We really should tell them about Shakespeare. They’d probably understand a lot of Shakespeare’s themes.

P.S.: You may have missed it, but I was trying to make a West Side Story reference with that thing about antelope.

dc30-antelope-west-side-story

Life on Mars: The Hunt for Martian Dinosaurs

~ J.S. Pailly ~ 5 Comments

Can Mars support life? Is there anything living on Mars right now? It sometimes seems like Mars is desperately trying to convince us that the answer to both questions is yes.

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If you’re hunting for alien life in the Solar System, there are four places you should pay attention to: Mars, Europa, Enceladus, and Titan. Now a thought recently occurred to me—a thought that I’m sure has occurred to other people before: in an astrobiological sense, these four worlds sort of represent the past, present, and future.

  • Mars: a place where alien life might have existed and thrived in the past.
  • Europa and Enceladus: places where life may exist and thrive in the present.
  • Titan: a place where life might start to evolve and thrive sometime in the future (assuming it hasn’t started already).

Regarding Mars, there was clearly a time when rivers, lakes, and oceans of liquid water covered the Martian surface. There’s growing evidence that at least some of the organic chemicals necessary for life were also present. Therefore it’s easy to imagine a time millions or perhaps billions of years ago when Mars had a biosphere as rich and robust as prehistoric Earth’s.

Obviously that robust biosphere is gone now. Even when we hear about the possibility that life still exists on present-day Mars, it’s generally assumed that this life would be only a remnant of what came before. The microbial survivors of whatever wiped out the Martian dinosaurs, so to speak.

Someday (hopefully soon), humans will travel to Mars. When we get there, we may find that all the Martians are long dead. That might seem a bit depressing, but actually I’m kind of excited by the idea that the fossilized remains of Martian dinosaurs might be there, waiting for us to come dig them up.

Sciency Words: Frost Line

~ J.S. Pailly ~ 10 Comments

Welcome to a very special holiday edition of Sciency Words! Today’s science or science-related term is:

FROST LINE

When a new star is forming, it’s typically surrounded by a swirling cloud of dust and gas called an accretion disk. Heat radiating from the baby star plus heat trapped in the disk itself vaporizes water and other volatile chemicals, which are then swept off into space by the solar wind.

But as you move farther away from the star, the temperature of the accretion disk tends to drop. Eventually, you reach a point where it’s cold enough for water to remain in its solid ice form. This is known as the frost line (or snow line, or ice line, or frost boundary).

Of course not all volatiles freeze or vaporize at the same temperature. When necessary, science writers will specify which frost line (or lines) they’re talking about. For example, a distinction might be made between the water frost line versus the nitrogen frost line versus the methane frost line, etc. But in general, if you see the term frost line by itself without any specifiers, I think you can safely assume it’s the water frost line.

Even though our Sun’s accretion disk is long gone, the frost line still loosely marks the boundary between the warmth of the inner Solar System and the coldness of the outer Solar System. The line is smack-dab in the middle of the asteroid belt, and it’s been observed that main belt asteroids tend to be rockier or icier depending on which side of the line they’re on.

It was easier for giant planets like Jupiter and Saturn to form beyond the frost line, since they had so much more solid matter to work with. And icy objects like Europa, Titan, and Pluto—places so cold that water is basically a kind of rock—only exist as they do because they formed beyond the frost line. This has led to the old saying:

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Okay, maybe that’s not an old saying, but I really wanted this to be a holiday-themed post.

Sciency Words: The Zero-One-Infinity Rule

~ J.S. Pailly ~ 6 Comments

Sciency Words MATH

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

THE ZERO-ONE-INFINITY RULE

I came across this term in Time’s special edition on Scott Kelly’s year in space, which I reviewed on Wednesday. The term was used in an article about astrobiology, but it actually originates in the field of computer science.

Zero-One-Infinity in Computer Science

The zero-one-infinity rule is sort of a rule of thumb. It’s credited to Dutch computer scientist Willem Louis Van Der Poel. According to this rule, a computer program should either never allow a certain event (zero), or it should allow it only once (one), or it should allow it an unlimited number of times (infinity).

The logic here is that it makes sense to not allow something to happen. It also might make sense to allow something to happen only once, perhaps as an exception. But programmers shouldn’t create arbitrary limits (according to this rule) on what a program can do. If you’re willing to allow something to happen twice, why not three times? Or four? Or thirty-eight? Or as many times as the user wants (computer memory space permitting)?

I don’t have a whole lot of coding experience, but the zero-one-infinity rule makes sense to me. It seems like a good rule, although I could probably think up more than one exception to the rule if I really wanted to.

Zero-One-Infinity in Astrobiology

Applying the zero-one-infinity rule to the search for alien life is, in my opinion, brilliant. How many locations in the universe can support life? There are really only three answers:

  • Life cannot exist anywhere in the universe (zero).
  • Life can exist only on Earth; Earth is a very special exception in a universe where life is otherwise not allowed (one).
  • Life can exist in an unlimited number of locations in the universe (infinity).

We already know the zero proposition is false.

There was a time (I remember it well) when many a scientist argued that Earth must be an exception: the one and only place in the universe where life could exist. Occasionally, I still hear people try to argue this.

All it would take is to find a second life-bearing world to prove the one proposition wrong (I’m looking at you, Europa). Because once we know about two living worlds, how could anyone argue that there can’t be three? Or four? Or thirty-eight? Or however many the universe feels like having?

Links

Zero-One-Infinity Rule from The Jargon File.

Willem Louis Van Der Poel from Wiki Wiki Web.