Astronomer uncovers the good, bad and WTF science of Prometheus

Phil Plait is an astronomer and major sci-fi geek. He writes the Bad Astronomy Blog for Discover Magazine and is also the host of the Discovery Channel's science show "Phil Plait's Bad Universe." You can follow him on Twitter at @BadAstronomer.

Spoilers ahoy! If you haven't seen Prometheus yet, then you might want to skip this scientific review of the movie, otherwise you'll feel as if vultures are eating your liver.

The much-anticipated flick Prometheus hit the theaters last week, and the reviews are, well, mixed. Personally, I liked the overarching themes it tackled—the origin of mankind, the origin of the aliens from Alien, the literal meaning of the phrase "head-explodey"—even if it stumbled, sometimes profoundly, on details.

OK, it slammed into a wall on some of the details. OK, fine, a lot of the details. Because some of the movie was awesome and some, um, not so much, I've decided to be fair and look over a couple of places where they got the science right, a couple where they didn't, and a couple where it could be interpreted either way.

The Good

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My favorite part of the whole movie was the planet itself. LV-223 was a terrestrial (that is, Earth-like) moon of a gas giant world. These types of planet/moons may exist!

The first planets detected around other stars were "hot Jupiters," gas giants circling very close to their stars. This was a profound shock to astronomers, since in our own solar systems we like to keep those massive planets out in the suburbs. But now we see planets at all distances from their parent stars.

That means there are probably plenty orbiting their star at the right distance for temperatures to be cozy. Our own gas giants have some huge moons—Saturn's Titan is bigger than Mercury!—so it's not a stretch to think there could be moons as big as Earth orbiting gas giants around other stars.

Another thing: as Prometheus approaches the LV-223 we see a caption telling us the planet is over 300 trillion kilometers from Earth (metric, yay!). That's 30 light-years! Yet it only took two years to get there, implying the ship has faster-than-light engines.

As a scientist, I acknowledge that FTL drives go against everything we know about physics right now. However, as a moviegoer, I'd rather not sit in the theater for the centuries needed to show a ship approaching some other star, so I'm OK with this.

What I like is that in the movie it's not explained, or even mentioned. Why? Because it's not important to the plot. All we need to know is that the FTL drive exists and works, but is slow enough that we still need to use "hypersleep chambers" for suspended animation. Done.

Explaining too much leads to mixed-up plots problems like Star Trek had with warp drive, and was unnecessary. And this movie had enough problems with the science it did need.

Speaking of which ...

The Bad

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OK, well, if the astronomy in the movie was relatively good, the biology in the movie was, um, not as accurate. Just as a couple of examples ...

In a key scene, scientist Elizabeth Shaw compares a sample of Engineer tissue to human DNA, exclaiming that it's a 100 percent match. The thing is, if you compared two humans' DNA you wouldn't get a 100 percent match! That only happens with identical twins. There are lots of DNA variations between humans, so a 100 percent match is literally impossible. And last I looked, we're not 8-foot-tall bald translucent bodybuilders with anger management issues.

It's possible that she wasn't checking the whole genome, just key gene sequences. Even then it's hard to buy; chimps match our DNA to roughly 98 percent (depending on what you're measuring), so a 100 percent match even on genetic "landmarks" is a big stretch with aliens so different from us.

The other big science moment that stuck in my craw (ooo, foreshadowing!) was when the biologist and geologist were trapped by the storm in the Engineer ziggurat. When the alien snake pops its head up, the biologist—who admits to being terrified of being on an alien planet just minutes before—approached the xenomorph and tries to make nice.

I mean, c'mon. Even when it flared its hood open, revealing something mouth-like but also enough like genitals to be seriously distressing, he just cooed at it like it's a kitten.

And he's a biologist! Has this idiot never seen a sci-fi movie?

He got what he deserved. Cripes, even Indiana Jones was scared of the cobra in the Well of Souls, and there was obviously a piece of glass between him and it.

The iffy

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The movie opens with an Engineer drinking some black goo on a primitive planet. He dissolves, and we see his DNA break apart and reform, becoming the basis for life on that planet.

This caused a lot of howls online, because people assumed the planet was Earth. But that's never actually stated, so it could just be a representative planet, showing us the Engineers went forth and multiplied.

The science is still iffy there, though. If you break apart DNA to its constituents, how does it know to reform itself to anything resembling DNA? It's like taking apart a car, putting the parts in a box and shaking it, then looking inside to see a fully formed but slightly different kind of car. DNA doesn't work that way.

It's possible that for us, the Engineers found a likely planet—Earth—and then guided the evolution to produce humans. But that's a pretty big stretch, since that would mean Engineers evolved independently of Earth, yet we share a lot of DNA with both them and every other organism on Earth. No matter how you look at this, it's got to be wrong someplace. Just not in the way most people think!

I loved the way tech was shown in the movie, and I do think it's entirely possible that someday we'll have things much like the computer displays, artificial intelligence, artificial gravity and robotic surgery depicted in the movie. But in a mere 70 years? Hmph. Advances in AI have been striking, but it always seems to be claimed that true AI just needs another 25 years. That's been said for 50 years.

Also, when Shaw crawled into that autodoc, all I could think of was how young that technology must have been, and how sharp all those instruments were. I hope the OS was Unix-based (you wouldn't want to get a virus HAHAHAHahahahaha! Heh). Clearly, though, when Prometheus takes place staple technology had advanced to the point where you can stitch up your abdomen and then leap over crevasses and lower heavy android bodies via rope. I can't even do that stuff with my current abdomen. Sign me up!

Another: my friend, the astronomer Neil Tyson, points out that during an argument Miss Vickers makes a comment about being "half a billion miles" from Earth, when in fact she was off by a factor of about 30,000. He's right, of course, but to be fair it sounded to me like she was just being a bit metaphorical. Even so, it would've been better for her to have said "trillions of miles," which sounds cooler anyway.

Clearly, I could nitpick the movie to death; a lot of science—stuff important to the plot, and not just little details—got messed up. At some level even I don't have a problem with science errors, but when they get to certain size, or occur at a critical moment, they become distracting. It's too bad, really, since with only a little nudge here and there this movie could have avoided some of the more egregious issues.

And as I said, handled properly, a lot of the big issues—like where we come from, how we got here, the role of religion in society—are a perfect fit for science fiction and would work well in the Alien universe. Some of them did work, but others were as out of place as, say, a tabby cat in a starfreighter's cargo hold.

And with that ... This is Phil Plait, last survivor of the website Blastr, signing off.

Phil Plait is a scientist and writes the Bad Astronomy Blog for Discover Magazine. While he is not 8 feet tall, he is baldish and somewhat translucent.