In the end of Portal 2, I fired the portal gun to the Moon. And it worked, which created a quantum tunnel between Moon's surface and Floor below Wheatley - sucking Wheatley out into space.

Throughout the entire Portal game series, we've seen that the highly experimental Portal Gun works only on white plain surfaces. To make a Portal on other plain surface, we even need to paint that with white gel. The surface of Moon is neither plain nor white. How did the Portal Gun work on it, then?

  • 11
    I wouldn't put it past Cave Johnson to have painted the moon with the gel.
    – Xantec
    Apr 20, 2013 at 13:50

1 Answer 1


Cave Johnson makes a reference to the White Gel being made of crushed moon rocks, which make a great portal conductor, indicating that the moon itself can also be portal-able.

From the Unofficial Portal Wiki:

According to Cave Johnson, conversion gel is made from ground-up moon rocks, which make a great portal conductor. This is shown when Chell fires a portal at the moon near the end of the game, despite the non-flat surface of the moon.

You can see the white gel explanation from this point in a Let's Play.

  • 5
    Making a white gel from moon rocks is a good trick given that the moon is actually nearly as non-reflective as coal: universetoday.com/35372/albedo Apr 20, 2013 at 15:07
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    @WayfaringStranger: The moon's surface is silica in a large part, which in a pure form is a bright white, and is also the biggest component of glass. A lot of a substance properties are determined by how it crystallizes, and what it's mixed with. Compare for example graphite (as in pencils) versus diamond. That's both just carbon, and one is solid black while the other is transparant. My point is that even if the moon isn't a super good reflector, that doesn't mean you can't make something white out of the material.
    – Joren
    Apr 20, 2013 at 18:30
  • @Joren: Sure, I'm just thinking about the dust on Neil Armstrong's boots. For certain, video game programmers would specify an elaborate refining process required to conjure up the good stuff. Apr 20, 2013 at 18:56
  • @WayfaringStranger The bigger question is, what's the big deal about moon rocks considering the moon is just a big chunk of Earth that got blown off a few billion years ago?
    – KutuluMike
    Apr 21, 2013 at 12:31
  • @Michael Edenfield, could be the fermionic Helium 3 content ofthe lunar regolith, brought in by solar wind, that makes for good portal paste. That theory'd make the white color somewhat optional,which is good because portal gun works when fired at the dark grey lunar surface. en.wikipedia.org/wiki/Helium-3 en.wikipedia.org/wiki/Fermionic_condensate Apr 21, 2013 at 17:08

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