SciFi Question

[Joseph Witchard]

When a space cruiser is about to be attacked, why does the captain always say "shields up"? Why do they not have their shields up 24/7?

And if you're wondering why I asked this question, the answer is yes, my entire day has been pretty uneventful:p Its highlights were reading in my XML book, my mom fixing homemade cheeseburgers, and watching Star Wars:p

[kender]

Beacusae shields draw power from engines, meaning that they cannot perform as well, travel as far and as fast with the shields up

[Charles]

More importantly, it gives the captain something dramatic to say. Something better than "Ho hum, we'll be fine. That's a lovely skirt you're wearing lieutenant. "

[Mayday]

Running with shields up all the time might give the impression that you're looking for trouble, should you run into another cruiser out in the cosmos.

After all, "Of course! We're one big happy Fleet." - Khan

[Charles]

Except that you ought to have the things up for when you hit a rock floating out in space or perhaps the occasional beer can.

[Joseph Witchard]

Interesting. Thanks:)

[NogDog]

All of which raises the question: what exactly are these shields? How do they stop missiles and/or lasers and/or beer cans from damaging the ship? How much energy (and therefore fuel) does it take to run them? What if the incoming missile is a 1 megaton nuke designed to detonate just short of your shields: can it stop the radiation, too? If so, does it stop radiation from getting out as well, causing all the heat and other radiation generated by your engines and systems to build up inside of it and cook your crew?

Eh, I guess it's a lot easier to just say you have something called dilithium crystals that generate huge amounts of energy and then tell Scotty, "More power to the shields!" ;)

[Sunny G]

Dilithium crystals control the mix of matter and anti-matter; on their own said crystals generate no power.

And with the shields up all the time, you can't use the transporter on anything outside them (at least in star trek).

[NogDog]

Dilithium crystals control the mix of matter and anti-matter; on their own said crystals generate no power.

And with the shields up all the time, you can't use the transporter on anything outside them (at least in star trek).

Glad we got the facts straightened out. Here I was thinking it was science fiction. ;) :p

[Joseph Witchard]

A thing to remember is that in Star Wars, ships still seem to run on liquid fuels. (Judging by a deleted scene from Revenge of the Sith.)

;)

[TecBrat]

I use Star Trek as the basis for the fictional universe in which I live. :D

That being said, it is not the shields that prevent rocks, debris and the occasional beer can from hitting the ship, it is the deflector. ("...we can re-route the signal through the main deflector dish...")

Shields would drain too much power if they were used all the time.

I can speculate that their stopping power could be inbound only, the way a one-way mirror (careful what you do in those fitting rooms) only reflects light from one side.