shield

In geology a shield is the central Precambrian rocks that form the core of a continent. Examples of shields are the Laurentian shield of North America and the Fennoscandian shield of northern Europe.

The stable part of a shield where no orogenic (mountain-building) activity takes place is called a craton.

In modern science fiction, especially popular entertainment, computer and video games, and other soft scifi, shields are a form of armor for starships and other self-powered and important objects or facilities. They usually involve a bubble of translucent or transparent energy around said object or ship that repels/absorbs/drops into another dimension incoming enemy attacks, or other things that can cause damage to things under the shield.

Shields come in a variety of flavors throughout scifi. In Star Wars they are powerful layers of invisible energy that are used to absorb the Multi-Gigaton level blasts fired from Heavy Turbo Lasers mounted on large capital ships. Another quite different instance are the sidewalls on capital class ships in the Honor Harrington book series, which repel physical attacks using large-scale gravity manipulating fields which are also used in engines. A third still striking example is in the Dune series of books, where shields are small enough to be fitted personally and capable of breaking the conservation of momentum and causing fusion explosions when they come into contact with weaponized laser beams. In Dune shields force people back to close range combat, to pierce the shields with slow moving objects.

The range seen here is evident of their purpose in science fiction. They answer the question of how do you keep the nuclear death rays from killing everyone on the heroic space rocket. They provide a plot point that changes the way combat must be executed in instances such as Honor Harrington or Independence War or Dune. They balance opposing forces in other instances to allow the ships and other facilities to absorb the enormous weapon yields of enemies, while at the same time allowing for incredibly destructive weapon systems, such as those in Star Wars or Star Trek.

Scifi in general is meant to allow for the re-use ideas and stories from classic works and bringing them to a limitless frontier. Shield technology is one of the bridges to bring classics into new worlds; Horatio Hornblower can't say "shields up, all ahead full" but Captain Harrington can.

Shield technology can be the way a science fiction book proclaims its alienation from what we understand to be possible. A bubble of translucent technological blue that protects our heroes from searing painful or nigh instantaneous death. It is a device of the plot that allows for a change in the way people and ships interact and add rules to the way combat occurs in the story.

Shield types Petra: Small light shield of Greeks and Macedonians. Possibly the same as 'pelta' or peltarion, which is noted as being both crescent shaped and round. I suspect the 'crescent' shaped may refer to it's concavity. In any case, smaller then the Clipeus, and carried by skirmishing infantry (Peltasts). http://uoregon.edu/~klio/maps/gr/peltast2.jpg is the image provided, by may be made up. Cetra/Targe: Small round Celtic shield, w/ center spike. Laminated wood? Parma: Small round Greco-Roman shield, strongly made, used metal in construction. Scuta: Large rectangular Roman shield; concave. 2.5' wide by 4' tall. -Early scutari are sometimes oval?

Clipeus: Large round Greek shield; held using strap (balteus)and central handle (umbo). Concave. Wicker base, covered with ox-hide and edged with metal. Used by Homeric heroes, it later shrank in size. Later the balteus and central handle were discarded in favor of a series of ties. Gallic: Large oval Celtic shield, w/ boss. Probably laminated wood. Hoplon/Argive: Greek shield built around wood core, using balteus and grips? 15.5 lbs., 30-39" diameter, used in shield wall.

Shields in Phalanx listed as protecting more the person to the left then the person holding the shield; center boss may have been used as a place to 'hook' the elbow, so more then 1/2 of the shield covered the next person in line.

Shield (?), n. [OE. sheld, scheld, AS. scield, scild, sceld, scyld; akin to OS. scild, OFries. skeld, D. & G. schild, OHG. scilt, Icel. skjoldr, Sw. skold, Dan. skiold, Goth. skildus; of uncertain origin. Cf. Sheldrake.]

1.

A broad piece of defensive armor, carried on the arm, -- formerly in general use in war, for the protection of the body. See Buckler.

Now put your shields before your hearts and fight, With hearts more proof than shields. Shak.

2.

Anything which protects or defends; defense; shelter; protection.

"My council is my shield."

Shak.

3.

Figuratively, one who protects or defends.

Fear not, Abram; I am thy shield, and thy exceeding great reward. Gen. xv. 1.

4. Bot.

In lichens, a Hardened cup or disk surrounded by a rim and containing the fructification, or asci.

5. Her.

The escutcheon or field on which are placed the bearings in coats of arms. Cf. Lozenge. See Illust. of Escutcheon.

6. Mining & Tunneling

A framework used to protect workmen in making an adit under ground, and capable of being pushed along as excavation progresses.

7.

A spot resembling, or having the form of, a shield.

"Bespotted as with shields of red and black."

Spenser.

8.

A coin, the old French crown, or 'ecu, having on one side the figure of a shield.

[Obs.]

Chaucer.

Shield fern Bot., any fern of the genus Aspidium, in which the fructifications are covered with shield-shaped indusia; -- called also wood fern. See Illust. of Indusium.

 

© Webster 1913.

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Shield (?), v. t. [imp. & p. p. Shielded; p. pr. & vb. n. Shielding.] [AS. scidan, scyldan. See Shield, n.]

1.

To cover with, or as with, a shield; to cover from danger; to defend; to protect from assault or injury.

Shouts of applause ran ringing through the field, To see the son the vanquished father shield. Dryden.

A woman's shape doth shield thee. Shak.

2.

To ward off; to keep off or out.

They brought with them their usual weeds, fit to shield the cold to which they had been inured. Spenser.

3.

To avert, as a misfortune; hence, as a supplicatory exclamation, forbid!

[Obs.]

God shield that it should so befall. Chaucer.

God shield I should disturb devotion! Shak.

 

© Webster 1913.