Contradictions in sci-fi shields

[blaughli]

I watch a lot of Star Citizen streams, and a big part of that game is being able to fly to and from planetary atmospheres. I don't understand the SCI part of the sci-fi shields that space game ships have, and I have some questions. The shields seem to always be on... does that mean that, like bullets, air molecules bounce off of the shields and never make contact with the ship? If that's the case, then ships themselves wouldn't need to be aerodynamic, right?. Also, if that's the case, then how do ships propel themselves, whether in atmosphere or in space? If the shield blocks projectiles or energy weapons, how would engine exhaust particles escape and propel the ship? How would a ship's weapons pass through the shield?

I'm assuming that the answer these questions is "it doesn't matter, it's not the job of sci-fi to make sense." But I can't stop thinking about this since shields are so prevalent in sci-fi. A possible "explanation" is that shields somehow selectively block incoming attacks but not outgoing things or incoming... air molecules.

 

[Vanadium 50]

I'm assuming that the answer these questions is "it doesn't matter, it's not the job of sci-fi to make sense."

Good assumption. Particularly for games.

ships themselves wouldn't need to be aerodynamic, right?

They are aerodynamic because that makes the shields work better. (In more detail, the ablative carrier wave is disrupted. If you don't make the ship aerodynamic, you need to realign the transparent polarity units with magnesite-nitron grappler. )

But I can't stop thinking about this s

Hope this helps.

 

[hmmm27]

I used to play Freelancer (Eric Roberts' previous game) a lot... like, a *lot* ; there was plenty of incongruencies, few of which made the game less enjoyable : still plenty of depth.

I'm stoked that he finished Star Citizen (FL got taken over by Microsoft probably about 3/4 of the way through development - their final product worked, but could've used more polishing) : going to check out some YT vids myself, maybe join up, if I can get a not-too-shabby gaming rig up'n'running (currently on a business laptop).

 

[blaughli]

Good assumption. Particularly for games.
They are aerodynamic because that makes the shields work better. (In more detail, the ablative carrier wave is disrupted. If you don't make the ship aerodynamic, you need to realign the transparent polarity units with magnesite-nitron grappler. )
Hope this helps.

Ah yes, this helps a lot. Thank you!

 

[member 656954]

@blaughli, sci-fi is a broad church and it includes shield handwavium where the issues that you describe are just ignored for the sake of the story, to plausabilium where authors include the complications of shields that need to be turned on and off, or where there is a soft spot in the shields for exhaust to escape. In the latter case, the capital ships are usually swarmed by fighters or missiles that target their rear, hoping to land a shot that destroys or cripples the craft.

But selective blocking is handwavium pretty much across the board. Shields are not usually opaque so the crew can see out, yet they somehow stop incoming lasers. Now that's technology

I've read a few stories where shields are opaque, and the authors make that an interesting aspect of warfare, as you have to time your blind spot so you can defend and then attack without being blasted to smithereens, but that's rare storytelling. (So rare, I can't even recall those novels, sorry!)

The other handwavium aspect is shaped shields. A lot of authors assume these, but really, they're magic. I recall a story where opaque bubbles that stopped time started appearing randomly on Earth and everyone initially assumed they were hemispheres. Then someone tried to dig their trapped family out and found they were spheres. That's always seemed the most likely shield effect to me. Impervious bubbles, spherical in shape, self-contained until the batteries expire.

 

[blaughli]

@blaughli, sci-fi is a broad church and it includes shield handwavium where the issues that you describe are just ignored for the sake of the story, to plausabilium where authors include the complications of shields that need to be turned on and off, or where there is a soft spot in the shields for exhaust to escape. In the latter case, the capital ships are usually swarmed by fighters or missiles that target their rear, hoping to land a shot that destroys or cripples the craft.

But selective blocking is handwavium pretty much across the board. Shields are not usually opaque so the crew can see out, yet they somehow stop incoming lasers. Now that's technology

I've read a few stories where shields are opaque, and the authors make that an interesting aspect of warfare, as you have to time your blind spot so you can defend and then attack without being blasted to smithereens, but that's rare storytelling. (So rare, I can't even recall those novels, sorry!)

The other handwavium aspect is shaped shields. A lot of authors assume these, but really, they're magic. I recall a story where opaque bubbles that stopped time started appearing randomly on Earth and everyone initially assumed they were hemispheres. Then someone tried to dig their trapped family out and found they were spheres. That's always seemed the most likely shield effect to me. Impervious bubbles, spherical in shape, self-contained until the batteries expire.

Thank you for this thoughtful exposition. I really appreciate hearing your thoughts, as it appears as though they have been developed over a rich life of handwavium and plausabilium navigation. It's great to know that others are out there dealing with these troubling issues, and that life can go on even if the answers will never appear. I especially like your example of one-way opacity, where light can leave but not enter. Get on it, scientists!

 

[Rive]

sci-fi is a broad church and it includes shield handwavium where the issues that you describe are just ignored for the sake of the story, to plausabilium where authors include the complications of shields...

Well, that's why I keep BSG in so high regards: no shields, and at the end the ship looks just like it should after a few years of beating
It is different issue that their handwavium quote was spent on the end of the story instead

 

[DrStupid]

The shields seem to always be on... does that mean that, like bullets, air molecules bounce off of the shields and never make contact with the ship?

There are no air molecules in the game. Air exists in the in-game physics but there is no corresponding collision detection. To my knowledge only gas exchange bewteen rooms and different physics grids is actually simulated (and even that doesn't work correctly at the moment). Everything else is fake. Thus the question is not how air molecules interact with shields but what the developers have in mind. They don't care about real physics but about cool visual effects and gameplay (unfortunately in this order). It seems Chris Roberts doesn't even know what a full Newtonean flight model actually means (e.g. no speed limit in space).

 

[stefan r]

@blaughli

...I've read a few stories where shields are opaque, and the authors make that an interesting aspect of warfare, ...

Opaque shields are found in historical fiction, actual history, contemporary fiction and current events news.

Here is a training video. Notice they have big shields that are transparent. They also have little shields that they can see through but are opaque to damaging radiation. They demonstrate using projectile weapons with shields at 1:55.

 

[member 656954]

Opaque shields are found in historical fiction, actual history, contemporary fiction and current events news.

It's not quite the same as a science fiction space ship, though Most shields in novels and cinema are visible light transparent.

They also have little shields that they can see through but are opaque to damaging radiation.

Not sure what you mean there, @stefan r? Are you referring to something like the Gentex Dazzle Visors? But couldn't you could readily burn through a transparent shield with high intensity radiation, like a gamma ray beam?

 

[stefan r]

Not sure what you mean there, @stefan r? Are you referring to something like the Gentex Dazzle Visors? But couldn't you could readily burn through a transparent shield with high intensity radiation, like a gamma ray beam?

I was referring to the sunglasses worn in the video. They block damaging UV light. Autodark welding helmets would be a good shield demonstration too. Welding helmets protect from soft x-rays and UV-C and cut out most of the visible light too.

Gamma rays are hard to produce, hard to focus, and hard to aim. The SWAT team's shield and armor doesn't do much good for them if you run them over with a cement truck. Volcanic lava flows will effectively defeat most bunker designs. There is usually a trade off between firepower and armor. Micro-black hole binaries and proximity supernovas will take out any targets. If your enemy has to resort to deploying black holes then your planet's defense was probably overkill.