The trouble with science is that sometimes it gets in the way.  Take for example a popular science fiction trope – going “out of phase”.  In essence, the protagonist has a gadget or a power caused by radiation or some similar thing, and they become able to pass their hands through solid objects.  Sometimes nobody can see them, sometimes it only works when they want it to.

Pretty useful, right?  You can stick your head through walls to check what’s on the other side, get into places that are locked, and if you’re invisible you can listen to all sorts of conversations that you shouldn’t.

However, the problem with it was ably demonstrated by “Wormhole X-treme”, an episode of Stargate SG-1 in which Martin Lloyd, an alien TV producer, has started a show based on the secret government project.  In this scene, one of the actresses is questioning him and the director about her character’s plot.

REESE Ah I’m having a little trouble with Scene 27. It says that I’m out of phase which means I can pass my hand through solid matter or I can walk through walls.

DELUISE Yeah. Cause you’re out of phase.

MARTIN Exactly.

REESE How come I don’t fall through the floor?

Martin and Peter stop. They look at each other and then back to Reese.

MARTIN We’re gonna have to get back to you on that one.

Floors (and ceilings) are made of matter.  If you can’t interact with it, then one of two things should happen.  Either gravity still affects you, and you fall to the centre of the Earth, where you are trapped forever, slowly starving to death (because you can’t interact with the hot magma on the way, so you don’t die, and you can’t interact with food either), or gravity doesn’t affect you, in which case you go spinning off into space as the Earth continues its orbital path.

In either case, the outcome is not good for you.