Monthly Archives: January 2010

aliens, extrasolar planets, sci-fi movies

Alien Worlds in SciFi Movies

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Avatar’s Pandora is Beautiful

But Too Good to be True

So, we went to see Avatar last night — in glorious 3D at the IMAX theater.  It’s a beautifully rendered film and I was reminded of scenes from the game Uru (which, nearly a decade ago had similar lovely landscapes).  I won’t go into the storyline in case readers haven’t seen the movie yet, but I’d like to use the world Pandora (where the movie’s action takes place) as a way to talk about other worlds and why they’re never going to be quite like they’re portrayed in the movies.  We’re all pretty used to seeing alien worlds in movies like the Star Trek franchise, Star Wars and others.  There’s a long tradition in science fiction (movies and print) of casting them as places where humans can go and explore. Hence, they kind of have to be places where humans can exist, even if they can only do it in space suits and habitats.  That’s okay — most of us have grown up knowing that humans on the Moon or Mars will be wearing space suits for a long time.  And, that will probably be the case on at least some planets that humans may one day explore beyond the solar system.

However (there’s always a gotcha), the planets have to be at least somewhat approachable and not be instant deathtraps for human explorers.  Io, in our own solar system, is a place that might be fascinating to explore, but it’s embedded in a deadly zone of radiation trapped within Jupiter’s magnetosphere.  While you could theoretically send humans there, they’d have to be really well protected — not a simple thing to do!  And, their habitats might not last very long, shortening their useful exploration time.

Pandora is a planet that seems to be set next to a Jovian-type planet in the movie Avatar. As such, if this Jovian planet is anything like the solar system’s Jupiter, there’s bound to be a HUGE magnetic field emanating from it, and magnetic fields trap charged particles. Where you have charged particles, you get radiation — and voila, Pandora could well be a deathtrap for humans. Yet, in the movie, there are humanoids living there on a lush, green world that defies current understanding of how such a world could exist next to a gas giant. And, there ARE humans there, and we ARE told that Pandora’s atmosphere is deadly to the humans but not the native humanoids.   The humans walk around with masks on (presumably sucking in oxygen), but are otherwise dressed in shirtsleeves.

So, deadly atmosphere and a presumed high-radiation environment don’t exactly say “run around in t-shirts and shorts with a mask on” to me. But hey, I’m willing to suspend disbelief for the sake of the story — I just won’t suspend the laws that govern planetary atmospheres and magnetospheres.  As beautiful as Pandora is in the movie — and hey, I hope that we DO someday find a planet as beautiful as it is — it can’t really exist in reality in the given circumstances of the movie (i.e. smack up next to a Jovian planet, embedded in its magnetosphere, and very likely also feeling the force of the Jovian’s gravity via tidal forces).

That’s just one science quibble I have with the movie. There are others — but I think you see where I’m going with this. Real-life planets around other stars are going to be far more alien than our filmmakers can imagine. They’re going to have their own life forms and appearances and environments that follow the laws of nature.  I think that someday, when our descendents are exploring those worlds, they’ll look back on our movies (if they have access to them) and probably laugh at how simplistic our viewpoint was — that we could remake worlds in our own imaginations and image and ignore the science that governs how worlds are created and how they evolve (with life or without).

All that being said, I really enjoyed the movie. I’ll probably see it again just to catch some details in the story and sets that I missed the first time around.  As long as I (and you) go into it with eyes open to the nuances and enjoy it for what it is, that’s cool.

For another scientist’s viewpoint on Avatar, go to Seth Shostak’s discussion here.

Enjoy!

Earth science, earthquakes, planetary science, tectonism

Tectonism Rules

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How Earthquakes Happen

In light of last week’s horrible earthquake in Haiti, I thought I’d talk a little about the forces of nature behind such events.  Despite what you may have read or heard on TV via the mouth of a certain science-ignorant televangelist, earthquakes are entirely natural events that happen when some part of Earth’s surface experiences violent vibration.  What causes the vibration?

The vibration is caused when energy is released in Earth’s crust.  This energy may be generated when segments of the crust are somehow jostled.  A nearby volcanic eruption can release energy that vibrates Earth’s crust.  In some rare cases, an underground explosion or collapse of an underground cavern can also cause an earthquake.

The most destructive quakes — like the one in Haiti — are caused by dislocations of the crust.  At first, the crust will bend (and remember, the crust is made of rock and rock can bend before it will break).  Eventually, if the stress is strong enough, if the energy released is strong enough, the rocky crust will snap. When that happens, you get vibrations called seismic waves. These seismic waves travel out from the place where the crust broke, and they shake the upper part of the surface.  That shaking is what damages and/or destroys buildings, highways, and bridges.  Some earthquake waves can actually be heard, but mostly they can be felt. The U.S. Geologic Survey has a wonderful primer on earthquakes that I recommend you check out.

Earthquakes are part of a larger process that modifies the surface of our planet over time — that process is called tectonism.  It’s the faulting or folding or other deformation of the outer layer of a planet. Tectonism is driven by forces within the world it affects (and yes, other places have tectonism).  Earth, for example, has tectonism driven by heat from the core, which affects the layers above it. Our planet’s continents ride on rock plates that move against each other as the planet turns. Motions of the plates reverberate through the layers of rock they carry, and this can cause earthquakes (through a complex chain of events). They also (over millions and millions of years) can do such things as form mountain ranges (the Himalayas are a good example).

Plate tectonic movements measured by GPS devices. Courtesy NASA. Click to tectonify.

How do we know all this?  Scientists monitor the motion of Earth’s crust through a variety of methods including seismic sensors (such as GPS ground sensors, see the map at left) and core samples of rock that have been drilled out.  By looking at the rocks in the cores, they can understand the formation history of the rocks and any stresses that have been applied to them by movements of the crust. They can also look at surface features and by understanding how they were formed, also understand the crustal movements that caused them to form.  It’s pretty standard geology work.

Earthquakes, as terrible as they can be, are a natural phenomenon caused by natural processes within our planet. We see evidence for quakes elsewhere in the solar system, as well.  Understanding earthquakes helps us understand the interiors of the worlds they affect and the science is fascinating.

The effects on humans on Earth when a quake hits are not so fascinating. They’re downright sad and horrifying. All the understanding of the science doesn’t help us when we are confronted by the pain and suffering these geological actions cause.  What we as humans living on an earthquake-prone planet should do is help those who are affected by others who are hurt or damaged during a quake.  What we shouldn’t do is make hateful statements that contain NO scientific accuracy about why earthquakes occur.  That’s what the televangelist I referenced above did. He proved his ignorance and hateful politics pretty well  by blaming the earthquake on what he thinks is voodoo (he has no evidence for this). He really thinks that the actions of Haiti’s earlier inhabitants in seeking political freedom caused the earthquake. He also has no evidence for that statement either.

I mean, this guy actually believes what he’s saying?  If so, he’s been pwnd by some pretty serious ignorance. And that calls into question the accuracy of everything else he “preaches”.

As a representative of the Christianist faction in American politics, this “man” comes across as representing millions of people who are Christians, who ARE scientifically literate and, as far as I know, DON’T hate on the basis of tectonic motion.

Why anybody would take this jerk seriously, particularly in matters of science, is beyond me. I wouldn’t go to a banker for medical advice. I wouldn’t go to a scientist to learn about theology.  It’s been made abundantly clear that I certainly shouldn’t ever go to a preacher to learn about science. Above all, I wouldn’t trust a hateful man who primarily makes his money off of other people’s faith (and lives in wealth and luxury on the proceeds of his “work”) to know anything about human dignity, morality, ethics, and sympathy — much less science or natural processes.

Earthquakes are not caused by voodoo. Quakes are not the actions of a deity whose creator-followers make him out to be petulant and angry.  In fact, there’s no scientific proof that deities are involved in earthquakes.  Anybody who tells you that some annoyed sky daddy causes earthquakes to punish people with suffering and death is an idiot. Pure and simple. Earthquakes are an entirely natural process that occurs on Earth. Science has done an excellent job of telling us how they work and what causes them.

If you want to help people affected by the Haitian earthquake, there are a number of places online to guide you to the right place. The Red Cross and Doctors Without Borders are good places to start. I’m sure there are others — so, if you can help in a positive way, please do.