A Brief Hiatus

May 24, 2015

Internet friends, I’m taking a one-week blogging hiatus so I can spend some time working on Tomorrow News Network. I need to figure out what I want to do with that project going forward. If all goes well, I should be able to make some sort of announcement on the T.N.N. blog soon.

I’ll return to regular blogging on June 1st. The 2015 Mission to the Solar System will continue with a month-long visit to Mars—that planet that I, for one, have been looking forward to more than any other.

In the meantime, keep it sciency, everyone!


Sciency Words: Silicosis

May 22, 2015

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Every Friday, we take a look at a new and interesting scientific term to help us all expand our scientific vocabularies together. Today’s word is:

SILICOSIS

What’s the scariest thing about the Moon? Moondust.

My10 MoondustI’m glad you asked, Mr. Moon!

  • First, moondust gets all over your spacesuit. During the Apollo missions, astronauts found it was practically impossible to get all the dust off their spaceboots and spacesuits, possibly due to a sort of static cling effect. So astronauts wound up tracking a lot of this stuff back into the lunar lander.
  • Next, it gets in your air supply. Once all that moondust got into the lander, the Moon’s low gravity meant dust particles could drift about in the air a lot longer than they would on Earth—just waiting for someone to breathe them in.
  • Finally, it gets in your lungs. Roughly half of moondust is composed of fine grains of silicon dioxide. Essentially, moondust has the consistency of powdered glass. You don’t want that in your lungs.

On Earth, the inhalation of silica dust can cause a respiratory disease called silicosis. Symptoms include coughing, shortness of breath, and swelling or inflammation of the lungs. Those most at risk include miners and quarry workers, as well as anyone working in the glass manufacturing industry.

At least one astronaut reported experiencing silicosis-like symptoms while on the Moon. Future Moon missions and possible lunar settlements will likely involve longer-term exposure and higher risks of respiratory diseases.

So while this may sound like an odd piece of advise, given that the Moon is airless, please be careful about the air you breathe on the Moon.

P.S.: Silicosis or similar respiratory conditions will also be problematic for Mars missions. The surface of Mars is covered in iron oxide dust (a.k.a. rust). I for one don’t want to breathe in flecks of rust any more than I want to inhale powdered glass. Martian soil may also contain other as-yet-unidentified chemicals that could be hazardous to human health.

Links

Silicosis from MedLine Plus.

Don’t Breathe the Moondust from NASA Science.

The Mysterious Smell of Moondust from NASA Science.

Occupational Health: Lunar Lung Disease from Environmental Health Perspectives.

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Today’s post is part of Moon month for the 2015 Mission to the Solar System. Click here for more about this series.


I Like Big Moons and I Cannot Lie

May 20, 2015

Why is Earth so special? Why did life develop and thrive here and (as far as we know) nowhere else in the Solar System? These are questions scientists and science fiction writers alike must puzzle over. Part of the answer may involve Earth’s ginormous moon.

Please note: for the sake of clarity, I’ll refer to Earth’s moon as Luna in today’s post even though that is not the Moon’s official I.A.U. name.

Although Luna is not the largest moon in the Solar System (that honor goes to Ganymede), the mass ratio between Earth and Luna is way, way out of whack compared to other planet/moon combinations. A moon as large as Luna has no business orbiting a planet as small as Earth.

So what’s the effect of Luna’s relatively large size?

My09 Stability

Scientists have speculated that Luna’s gravity does more than create tides. It may also help stabilize Earth’s orbital axis.

According to at least some computer simulations, Earth could easily tilt sideways by as much as 85 degrees if not for Luna’s constant gravitational tug. This would lead to sudden and dramatic changes to the global climate. Changes that life might not be able to cope with.

If that’s true, then disproportionately large moons like Luna may be necessary for all life-bearing planets. Since Luna-like moons are surely rare, this drastically limits the chances of finding life elsewhere in the universe. Which totally sucks (not a scientific evaluation, just my opinion).

However, there may be other possibilities. For example, some simulations indicate that a moonless Earth could still keep itself balanced thanks to the gravitational influence of Jupiter.

The lesson for science fiction writers is that life-bearing planets probably need something to hold them steady. Whether that something is a Luna-like moon, a Jupiter-like planet, or some other large nearby object is up to the writer’s imagination. At least until science provides us with more conclusive data.

Links

Earth’s Stabilizing Moon May Be Unique Within Universe from Space.com.

The Odds for Life on a Moonless Earth from Astrobiology Magazine.

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Today’s post is part of Moon month for the 2015 Mission to the Solar System. Click here for more about this series.


Molecular Monday: What Do Aliens Breathe?

May 18, 2015

Welcome to Molecular Mondays, a relatively new series here on Planet Pailly. Every other Monday, we examine the atoms and molecules that serve as the building blocks of our universe, both in reality and in science fiction. Today, we turn our attention to:

ELECTRONEGATIVITY

Ever since I started this Molecular Mondays series, I’ve wanted to identify chemicals that could serve as alternatives to oxygen in alien biochemistries. My research eventually led me to the concept of reduction potentials, which has now led me to the more fundamental concept of electronegativity.

When atoms join together as molecules, they share each other’s electrons, but they rarely share equally. Certain atoms (notably oxygen) tend to hog electrons. Electronegativity measures how much electron hogging an atom is wont to do.

When considering how electronegative an atom is, we should ask two key questions:

  • How many protons are in the nucleus?
  • How many layers of electrons surround that nucleus?

Since protons have a positive charge, an atom with more protons can exert a stronger attractive force on nearby negatively charged electrons.

My08 High Electronegativity

But that attractive force is mitigated by the atom’s own electron shells. More shells mean less electronegativity.

My08 Low Electronegativity

Oxygen’s exceptionally high electronegativity means it’s very eager to participate in any chemical reaction that will give it more electrons, including the biochemical reactions that make multicellular life possible on Earth.

So what do aliens breathe if they don’t breathe oxygen? A quick look at the periodic table shows that several elements have electronegativities in a similar range to oxygen. So in terms of astrobiology, or at least in terms of writing science fiction, I believe two elements deserve special attention: fluorine and chlorine.


Sciency Words: Jiffy

May 15, 2015

Sciency Words MATH

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Every Friday, we take a look at a new and interesting scientific term to help us all expand our scientific vocabularies together. Today’s word is:

JIFFY

Imagine a vast, intergalactic empire with Earth as its capital. Gargantuan starships hurtle through space, traveling at velocities approaching or even exceeding the speed of light. Through commerce, exploration, and occasionally military conflict, humanity continues to expand its power in the galaxy. Now what could all this have to do with a word like jiffy?

Sometime around the turn of the 20th Century, physical chemist Gilbert Newton Lewis proposed jiffy as a unit of time defined as the amount of time it takes light to travel one centimeter in a vacuum. As far as I can tell, the term never caught on and is now a mere footnote in the scientific lexicon.

However, the way jiffies are defined, with their relationship to the speed of light, has some interesting implications in a universe governed by special and general relativity.

According to relativistic physics, our perception of time changes in relation to velocity, acceleration, and even gravity.

My07 Time Dilation

As a spacecraft approaches the speed of light, time noticeably slows down for the spaceship relative to the rest of the universe. For a ship traveling at the speed of light, time stops. If you somehow travel faster than light, some physicists predict time from your perspective would actually reverse. (Click here for a more comprehensive explanation of relativistic time dilation.)

If you hate time zones and jetlag, just think how much more complicated things might be in a futuristic space empire with starships zooming about the galaxy, experiencing time in different ways relative to each other and the rest of the universe.

I don’t know if jiffies (along with kilo-jiffies, mega-jiffies, etc) would ever be accepted as a regular part of space traveler jargon, but the relativistic effects of space travel might necessitate a whole new standard for measuring time, with a specialized system of units defined in relation to the speed of light. Maybe something similar to Gilbert Newton Lewis’s jiffy would be a good place to start.


We Choose to Go to the Moon Again

May 13, 2015

My06 Stuff on the Moon

Humanity will return to the Moon… eventually. We have a long list of reasons to do so. The most commonly cited reason is, of course, the mining of helium-3.

In nuclear fusion reactions, helium-3 can be used as a carbon-free, radiation-free fuel. So that would be awesome for the environment. Nuclear fusion also promises to generate more usable energy by far than any other currently available technology, thus solving the world’s energy crisis.

Although helium-3 is rare on Earth, it’s relatively common on the Moon. Once we establish lunar mining facilities, we could send this fuel back to Earth or use it to power spacecraft for further exploration of the Solar System.

But is this really the best reason to return to the Moon?

How Difficult Will This Be?

While helium-3 is more common on the Moon than on Earth, that doesn’t mean it’s easy to get. Lunar mining operations would have to sift through hundreds of metric tons of rock, heating that rock to temperatures in excess of 600 degrees Celsius, just to obtain a teeny-tiny sample of helium-3.

When you consider the total amount of energy needed to extract usable quantities of helium-3, combined with the cost of sending that helium-3 back to Earth, as well as the costs associated with shuttling astronauts and equipment to and from the Moon’s surface, you might find that you’re not getting much of a return on your investment.

Do We Really Need Helium-3?

At this time, nuclear fusion remains a promising but highly experimental technology. In theory, helium-3 is the idea fuel, but other fuels like hydrogen-2 could also work (although the fusion of hydrogen-2 nuclei would produce radiation in the form of free neutrons).

Since we can get hydrogen-2 right here on Earth, it may make more economic sense to use that instead.

The Future of Helium-3

In a more distant, Sci-Fi future, it’s a pretty safe bet that helium-3 will become a major energy source. Planetary economies will depend on it. Wars will be fought over it. Labor-class men and women will don spacesuit and go mining for it.

But I’m not convinced that this will be humanity’s top reason for returning to the Moon. Not when there are so many other, more achievable goals for our next Moon mission.

So what do you think will be the motivating factor when we finally do return to the Moon?

Links

Could Helium-3 Really Solve Earth’s Energy Problems? from io9.

How Nuclear Fusion Reactors Work from How Stuff Works.

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Today’s post is part of Moon month for the 2015 Mission to the Solar System. Click here to learn more about this series.


Ice Skating in Shackleton Crater

May 11, 2015

There’s one thing I’ve always wanted to do: go ice-skating on the Moon. It’s a dream I’m sure we’ve all had at some point. The best place to make that dream become a reality is Shackleton Crater… maybe.

Shackleton Crater is a lunar cold trap situated at the Moon’s geographic south pole. The exact pinpoint location of the pole lies on the crater’s outer rim. And the inside of the crater contains water ice, or at least some scientists think so.

In the mid-1990’s, a space probe named Clementine beamed radio waves into Shackleton. The radio waves bounced back in a manner that could be interpreted as a reflection off water ice… or possibly reflections off exceptionally rough, rocky terrain.

Later, analysis of data from NASA’s Lunar Prospector and Lunar Reconaissance Orbiter revealed a higher than average concentration of hydrogen in Shackleton Crater and other nearby craters. Since hydrogen is part of the water molecule, this could be more evidence of water ice. Or it could be evidence of some other hydrogen-containing molecule.

In 2009, NASA’s LCROSS Mission made headlines for “bombing the Moon.” A large projectile crashed into Cabaeus Crater, not far from Shackleton, and the resulting debris plume was observed to contain, among other things, particles of water ice which must have lain buried underground for billions of years.

Although a lot remains open to interpretation, the pattern of evidence seems to suggest that water ice is spread throughout the Moon’s polar regions, with Shackleton Crater possibly containing one of the largest deposits.

But before we start lacing up our ice skates, we should note a few things. Any ice in Shackleton is likely buried under layers of rock, similar to what was observed in Cabaeus. Also, we might only be talking about a few hundred gallons spread thinly over an area of several hundred square kilometers.

My05 Shackleton Ice Skating

Fortunately, my dreams of one day ice skating on Mars seem far more realistic.

Links

The Mystery of Shackleton Crater from Air & Space.

Evidence for Water Ice near the Lunar Poles from The Journal of Geophysical Research.

An Explanation of Bright Areas Inside Shackleton Crater at Lunar South Pole Other Than Water Ice Deposits from the 2013 Lunar and Planetary Science Conference.

LCROSS Impact Data Indicates Water on Moon from NASA.

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Today’s post is part of Moon month for the 2015 Mission to the Solar System. Click here for more about this series.

 


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