I know part of the explanation for why the event horizon on an open Stargate looks like water is it's the event horizon and that's how water reflects off of the event horizon.

But radio waves, which are part of the E/M spectrum, go through the event horizon, so light should, too.

Is there another explanation for the water look? And is there any real-world science behind this, or is it just a case of justifying the effect they selected for the event horizon?

  • 3
    FWIW, there are plenty of real-life examples of things that are transparent only to selected frequencies of radiation. For example, walls will block visible light but not cell phone signals or radio and TV broadcasts.
    – David Z
    Commented Feb 29, 2012 at 2:24
  • 1
    @DavidZaslavsky: Sounds like you've got the start of an answer there.
    – Tango
    Commented Feb 29, 2012 at 2:50
  • Yeah, but I don't know that much about stargate operation so I'm not sure where I could go from there. Someone else will probably have to fill out the rest of that answer.
    – David Z
    Commented Feb 29, 2012 at 4:14
  • 1
    Radio waves go through water too...but water still looks like water...
    – NominSim
    Commented Feb 29, 2012 at 14:08

1 Answer 1


Going by regular physics, it has to do with the refractive index (or how much light is bent by a transparent medium) of the event horizon. This is what makes a pencil submerged in water look bent. However, the extent of bending depends on the wavelength of the light or electromagnetic wave passing through the medium (which is why prisms can split colors).

The wormhole's event horizon looks like a reflecting pool probably due to the same reason that a mirage looks like one -- it bends visible light. Thanks to Einstein, know for a fact that the gravitational fields around blackholes (and wormholes) bend light. So both the reflective effect and the permeability to radio waves make some scientific sense.

P.S. If you're wondering why a gravitational field strong enough to bend light won't shred the person stepping into it -- that, I believe, is where Ancient technology comes in. They found a way to make the wormhole affect energy only. They transport matter by first converting it to an energy-based data stream, which is reconstructed at the receiving end.

  • 1
    Which considering energy has a matter equivalent, which is why lights path can be bent by the gravitational forces of a black hole, is quite a scientific achievement of the ancients.
    – Amicable
    Commented Sep 4, 2014 at 16:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.