<span class="SFPTagline"> From SCIFIPEDIA </span>

Invisibility is the state of being imperceptible to sight.

The adjective is "invisible."

Many sci-fi works feature the element of invisibility. This might be a constant state, or it might be achieved intermittently. It most commonly occurs voluntarily, although stories featuring involuntary invisibility exist.

The invisibility may be brought about through:

• Technology (such as the cloaking device employed by the Romulans in Star Trek)
• Magic (like Harry Potter's cloak of invisibility or Frodo's ring)
• Psychic means (The Shadow's ability to "cloud men's minds so they cannot see him")
• By moving so quickly the human eye cannot register the event (The Flash has done this)
• Being incorporeal (not having a body), like the ghost Topper
• Being a natural state of existence
• Existing on another plane of existence

Invisibility is sometimes selective. This is a common plot element with stories involving ghosts: only certain people may be able to see the ghost, and ghosts can usually see each other.

There are other types of "invisibility", such as radar invisibility, although that is a much broader use of the term. Technically, an occluded person (someone hiding behind an object) is invisible from the other person, but that is not common usage.

Cognitive invisibility is when someone (such as a ninja) is optically visible, but is presented in such a way that the observer simply takes no note of them. This may happen by blending into the environment, or by a subtle understanding of human perceptive triggers.

It has sometimes been a plot point that a human discovers a way to be cognitively invisible to a non-human opponent. It may be that the opponent can only detect heat, or only keys into a moving object.

Paranormal

Some reported supernatural beings are invisible. UFOs have been reported to be invisible. The Philadelphia Experiment is a rumored attempt to make a ship invisible, with unintended consequences. Donna Higbee, CHT, has also written about Spontaneous Human Involuntary Invisibility (HSII). Some mystics have reportedly been able to obtain the state, and it was part of the repetoire of the Ninja.

Related Terms and Articles

• Translucence is being see-through, but not transparent (like the Predator in the movie of the same name)

External Links

Donna Higbee on HSII

British military working on Invisible Tanks

To see specific books, movies, and so on, please click the category link at the bottom of this article.