Sciency Words: Ecotype

December 30, 2016

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.

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Life on Mars: The Hunt for Martian Dinosaurs

December 28, 2016

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

December 23, 2016

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.


What’s Up with Juno?

December 20, 2016

It’s been awhile since we checked in with Juno, the NASA space probe currently orbiting Jupiter. So Juno, how’s the mission going?

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Uh-oh. That doesn’t sound good. What happened?

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Okay, here’s a quick timeline of events:

  • On July 4, 2016, Juno entered orbit of Jupiter. The main engine worked flawlessly at the time.
  • On August 27, 2016, Juno performed its first science pass of Jupiter. All its instruments appeared to be in working order.
  • On October 19, 2016, Juno was supposed to shorten its orbital period from 53 days to 14 days, but there was a problem with the main engine. Plan B was to just do another science pass, but then there was a problem with the main computer.

According to this article from Spaceflight 101, we now know what happened with the computer, and it sounds like it’ll be a fairly easy fix. The malfunction was caused by an instrument called JIRAM. Continuing with our timeline:

  • On December 11, 2016, Juno performed another science pass, this time with JIRAM switched off. All the other science instruments seem to be in working order, and a software patch for JIRAM will be uploaded soon.
  • Coming February 2, 2017, Juno will approach Jupiter again. This will likely be another science pass, since NASA still doesn’t know what’s wrong with the main engine.

The main engine is turning out to be the real problem. According to a press release from October, some pressure valves that should have opened in a matter of seconds took several minutes to open. Until NASA figures out why that’s happening, they’re going to leave Juno’s orbit alone.

Juno can still perform its mission in its current 53-day orbit; it’ll just take longer. We’re looking at five years rather than the original year-and-a-half. That screws up the original science observation calendar, and the prolonged exposure to Jupiter’s intense magnetic field might lead to more computer glitches in the future.

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Fingers crossed.


Sciency Words: The Zero-One-Infinity Rule

December 16, 2016

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.


Time: A Year in Space, A Book Review

December 14, 2016

I was thoroughly unimpressed by Time Magazine’s “Mission to Mars” special issue, which I previously reviewed here. But I wanted to give Time another chance, so I ordered their “A Year in Space” special edition from earlier in the year.

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I’m pretty sure this is how the Year in Space mission began.

Quick Review

Not perfect, but much better than the Mars thing.

Longer Review

The writers provide a fairly decent overview of Scott Kelly’s year in space mission. They go into some detail about a few key science objectives… but you can find that sort of information basically anywhere. In that respect, this magazine is no better or worse than reading Space.com.

What’s far more interesting are all the little anecdotes about daily life aboard the International Space Station. There were plenty of little details I’d never heard about before. In a few cases, I got answers to questions I’d never thought to ask.

My personal favorite was a photograph of the space station’s kitchen counter (page 34). It has magnets attached to it, because how else are you going to keep your silverware from floating away? And for everything that’s not metal, the kitchen counter also has Velcro. Again, this is a very small detail, but it’s something I never knew and never even thought about before.

We also get a little insight into the psychology of an astronaut, with little quotes and stories from Scott Kelly, his twin brother Mark Kelly, and a few others who’ve either been to the ISS or served in other space missions.

It’s not much. It’s nothing super deep or profound. But it does help humanize space exploration just a bit. You don’t get them from most books or articles about space, or at least I don’t. For that reason alone, I’d say this magazine is worth a read.


Exoplanet Explorer: Orbitar

December 12, 2016

Today’s post is the first in what I hope will become a semi-regular series about exoplanets: planets that orbit stars other than our Sun. I’ve decided to start with an exoplanet named Orbitar.

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In December of 2015, the exoplanet designated 42 Draconis b was officially renamed Orbitar following a public naming contest held by the International Astronomy Union. Orbitar is a gas giant planet orbiting a red giant star approximately 315 light-years away in the constellation Draco.

Discovering Orbitar

The gravitational pull between planets and the stars they orbit causes stars to wobble in place. When the star 42 Draconis was found to wobble at a regular interval of 479 days, it was determined that a large planet with a 479 day orbital period was likely responsible.

Further calculations determined that this planet had an average orbital distance of 1.19 AU and an orbital eccentricity of 38%. The planet’s total mass was estimated to be equivalent to at least 3.88 Jupiters, give or take 0.85 Juptiers.

Life on Orbitar’s Moons?

According to the Brevard Astronomical Society, the group that won the IAU naming contest for Orbitar, “this closely orbiting gas planet could possibly host moons with Earth-like characteristics in the so-called habitable zone.”

Personally, I feel that’s a bit over-optimistic. At an orbital distance of 1.19 AU, Orbitar and its hypothetical moons would certainly would be within our Sun’s habitable zone, but 42 Draconis (which was renamed Fafnir in the IAU contest) is over twice our Sun’s age and has entered the red giant phase of its life cycle.

I may be wrong about this, but I’d expect that Fafnir’s habitable zone would lie well beyond the 1.19 AU distance. Orbitar’s moons (if they exist) should have been charred to cinders by now.

However, that still leaves us with the possibility that Orbitarian life could have existed at some point in the distant past, when Fafnir was still young and still a main sequence star like our Sun.

P.S.: As far as I can tell, the name Planety McPlanetface was not submitted to the IAU’s planet naming contest.

Links

Orbitar, Really? Some New Exoplanet Names Are Downright Weird from Ars Technica.

Planetary Companion Candidates Around K Giant Stars 42 Draconis and HD 139 357 from Astronomy & Astrophysics.

Name Exoworlds: An IAU Worldwide Contest to Name Exoplanets from the International Astronomy Union.