SF Tech question: Making Light of Heavy Things

[Ordinary_Guy]

Originally Posted by MadScientistMatt

...And it's not like not knowing that such a thing is possible is an obstacle in science fiction. After all, that is very different from knowing that something is not possible.

True. And important.

Originally Posted by MadScientistMatt

As the laws of physics stand right now, if you plugged a negative value for an object's mass into the gravity equations, you'd have a reversed gravity force... but what does a negative mass value mean, and would such an object behave backwards in other equations like F=ma?

As I understand it (which is sketchy at best), if you plugged a -1 in, say, the proper mass M of the Lorentz equation, you'd have an "imaginary proper mass." That's not to say Lewis Carroll is doing the math, nor is it plucked from the dark end of a creative physicist, but it's the mathematical term for negative square roots (which, as far as I know, do not inherently violate any laws of conservation).

[Pthom]

Originally Posted by dclary

... There is a new model for flight theory, called the physical model, based on Newton's work, instead of Bernoulli's, which better explains and accounts for aspects of flight that the "lower air pressure" model does not.

I'll leave the experts to explain it more fully:

http://www.aviation-history.com/theory/lift.htm

Great link. We old farts were taught all kinds of wrong information, it seems. I'm curious, though, about the boat sail. (I've done some sailboat racing, never flown an aircraft.)

The familiar triangular sail of the sloop (and its predecessor the lateen) allow boats to sail "into" the wind a bit, by functioning (as I was taught) like a wing. The wind passing across the fabric of the sail forms it into a similar curve (as seen from above) as that of a typical aircraft wing. The boat is pulled a bit in the direction of the bulge of the sail, even though the wind direction is quartering across the bow toward the stern. The keel or daggerboard (or centerboard or leeboard or oars...) keep the boat from sliding across the water. Perhaps the physics is the same, upwash and downwash, but horizontally instead of vertically?

Originally Posted by Ordinary_Guy

... Did they really have a clue about the nature of lift back when... ever this boat sail was used? Or was it serendipity and they just hung on to it?

I doubt anyone in ancient Egypt had a clue about it any more than I do (see above). But they discovered that by hanging a big triangular sheet from a pole, they could get boats to move more or less upwind. Why later boats, such as Columbus's caravelles used square sails (which do work this way to a much lesser degree) is beyond me. Guess it goes to show that no matter how great our discoveries, over time, we forget important stuff and have to rediscover it later.

Penicillin is made from what?

[ChunkyC]

Funny how things align sometimes. Last night on PBS I watched a show on string theory and how the big-brains are trying to unify gravitation with the strong and weak atomic forces and electromagnetism. Extra dimensions, open or closed strings ... my brain was definitely hurting by the end of the show.

The only problem is, it appears that there are currently five different string theories and the boffins aren't quite sure which one describes this universe if any of them actually do.

And I can't figure out how to use the memory function on my calculator.

[dpaterso]

I confess this "new" lift theory talk confuses me, I'm not an aeronautical engineer but I never thought that lift was only the result of air passing over the surface area of a wing, we've all seen wind tunnel experiments on film and there's complex patterns at work around the wing as much larger air volumes are disturbed and swirl back. It's nice of someone to go to the trouble of producing little charts an' stuff but, no real surprises there.

Wings, who needs 'em anyway, strap a dozen big dumb boosters together and step back.

Golden Age Sci-Fi also subscibed to the pressor beam theory, the inverse of the old tractor beam staple. Equip a craft with both types of projectors and you can maintain your altitude and "walk" to your destination. What if you aim your tractor beam at the Moon... at Mars... at a distant star? And "brake" using your pressor beam.

The Martians of course were defying gravity millions of years ago:

"Eighth Ray or Antigravity Ray is the ray of propulsion. It repels aircraft from gravity and is used in buoyancy tanks. It allows all Barsoomian aircraft to hover anywhere. It is an inherent property of all light." (ERBzine 0248)

Eh, brain fart over, carry on please...

-Derek
My Web Page - naked women, bestial sex, and whopping big lies.
Take the critiques you get with a grain of salt. Invariably, some of the critics will be kooks, bitter curmudgeons, or complete fools. ~odocoileus

[PeeDee]

So how come Qui-Gon and Jar-Jar weren't mashed to jelly by the force of the repulsors when that troop carrier drove over them?

Because the world is a cruel place.

I think this was explained that the repulsors were coming out of the side of the transports, sort of like the wheels on the sides of a car. Qui-Gon and Jar Jar were in the undercarriage part where there was no repulsion field.

[TheIT]

Originally Posted by PeeDee

Because the world is a cruel place.

I think this was explained that the repulsors were coming out of the side of the transports, sort of like the wheels on the sides of a car. Qui-Gon and Jar Jar were in the undercarriage part where there was no repulsion field.

So they got lucky? Darn...

It does make it interesting to consider that whoever pilots one of the transports needs to be certain they don't fly over anything fragile. Wouldn't they also be leaving a pretty wide trail?

[PeeDee]

Originally Posted by TheIT

So they got lucky? Darn...

It does make it interesting to consider that whoever pilots one of the transports needs to be certain they don't fly over anything fragile. Wouldn't they also be leaving a pretty wide trail?

The thing about Star Wars is, you can explain it away only to a point, and then you have to shrug and go "Well, I guess their technology just works that way, damn it."

The trail that it seemed to be leaving was mostly a wind-blown trail, so it seems less like something heavy had just powered over the grass and more like something on a high gust of wind had just gone by. Star Wars technology was never a reliable thing.

Now, I always thought that Babylon 5 did an extremely good job with every detail, from the way the Starfuries navigate, to how long it took their shuttles to get to neighboring sectors, to the station itself. If I recall, an early interview with Joe Straczynski said that they had worked closely with NASA scientists, who declared that the technology on B5 was very likely how these things would work in the future.

[ChunkyC]

Yup, B5 was superb that way. The only full-blown piece of bolognium in the basic tech of the show was the jump gates. And their CGI guys were astonishingly good. You're dead on about how the star furies maneuver, all the thrust jets ignite in the way you'd expect them to in order to rotate the ship as seen on screen. And in keeping with gravity -- they even had the zero-g at the longitudinal axis of B5 right, and used it to great dramatic effect in the episode where the Vorlon Kosh exits his encounter suit and finally reveals himself in order to save Sheridan's life. The whole show was brilliantly done.

[PeeDee]

Originally Posted by ChunkyC

Yup, B5 was superb that way. The only full-blown piece of bolognium in the basic tech of the show was the jump gates. And their CGI guys were astonishingly good. You're dead on about how the star furies maneuver, all the thrust jets ignite in the way you'd expect them to in order to rotate the ship as seen on screen. And in keeping with gravity -- they even had the zero-g at the longitudinal axis of B5 right, and used it to great dramatic effect in the episode where the Vorlon Kosh exits his encounter suit and finally reveals himself in order to save Sheridan's life. The whole show was brilliantly done.

Even without that, the writing was powerful enough to have steered the show through bad science...but it had good science, which helped immensely. I was willing to forgive them the Jumpgates, because they used them to good and interesting effect, and they never dwelt on them.

The fact that the Starfuries would continue flying forward, even if they were rotating to point in a different direction, always impressed me. It's not a lot of sci-fi which actually takes interia in space into account.

Star Trek sort of sidestepped the whole issue. Most science issues, come to it.

[ChunkyC]

Originally Posted by PeeDee

It's not a lot of sci-fi which actually takes interia in space into account

Nothing makes me shake my head more than a spaceship banking into a turn out in the interstellar void. I love Star Trek but I really wish they'd quit doing that. I suppose it would make sense to angle a large ship like that so that the deck always faced 'down', as in perpendicular to the direction of inertia, but Trek's ships had inertial dampeners, so that should have been irrelevant.

The guys who make these shows must hate peeps like us, lol.

[Soyarma]

Aside from the fact that it looks cool its probably energy saving to use the motion to assist the inertial dampers. A rapid turn without banking would put a lot more strain on the outer edge of the ship. Though the force of something like that is probably less than hitting interstellar hydrogen particles at warp 9.

[Pthom]

Why is there any worry about hydrogen particles for a ship in warp drive? Aren't they in some sort of alternate space-time 'place' that enables the FTL speeds? Think about this: if a ship was moving at just warp 1 (which I assume to be the speed of light, but I could be wrong so feel free to correct me), even collisions with single atoms would ultimately erode the hull away. There is a BUNCH of energy at atoms moving at light speed. No, warp drives MUST move ships through absolute vacuum. And anyway, isn't that what the bright flash of light means?

heh heh heh...I love this stuff.

[dpaterso]

The Blish short story collections (adaptations of TOS episodes) often had Enterprise cruising at Warp 4 which he equated to something like 64C (64 x lightspeed, not Centigrade). I don't know if he made that up on the spot or if he obtained info from Roddenberry.

But that's why starships have deflector arrays. To deflect any matter in their path.

-Derek
My Web Page - shameless vampyre fiction & other shameless writings.
Take the critiques you get with a grain of salt. Invariably, some of the critics will be kooks, bitter curmudgeons, or complete fools. ~odocoileus

[ChunkyC]

Yah, the Star Trek warp factors are a geometric progression. Trek tech says the warp engines create a bubble around the ship, so that would also presumably offer protection against ablation.

A rapid turn without banking would put a lot more strain on the outer edge of the ship.

But wouldn't the strain be there in the direction of the original course anyway? So the dampers would have to negate the same amount of force regardless of whether you rotate the ship to be belly down or not. (correct me if I'm wrong)

You'd have to use thrusters to rotate the ship, and that uses fuel. Unless they've got the mother of all perpetual-motion gyroscopes at the centre of mass of the ship, every pretty bank uses up more thruster propellant than just rotating the ship to port or starboard around its vertical axis. With a bank, you have to rotate the ship along the longitudinal axis as well as the vertical.

[Kevin Yarbrough]

From what I have seen and read some theorist think that gravity is nowhere near as strong as it should be. They are thinking that gravity is leaking into our world from and this accounts from why it isn't as strong as it should be. We are only getting a fraction of it.

They also seem to think that when to parallel universes collide it creates another big bang and another universe is created.

If things like gravity our leaking into our Universe that could mean that other things are as well. Black matter could be one of those.

Things leaking into our universe....that could be the start of a good book. Just what is leaking into our universe and what effect is it having on us?

[ChunkyC]

Heya, Kevin! Saw that Nova episode last night too? Wicked stuff.

Yeah, M-theory combines the five string theories into one, introduces an eleventh dimension, dimensions analagous to membranes or branes, open-ended strings attached to a single brane, closed strings able to leak between branes, parallel universes ... owie, my poor widdle cwainium.

I like the idea that if gravity (gravitons) are made up of closed strings and can therefore leak between parallel universes, we might be able to communicate with a parallel universe using modulated gravity waves.

[Ordinary_Guy]

Originally Posted by dpaterso

The Blish short story collections (adaptations of TOS episodes) often had Enterprise cruising at Warp 4 which he equated to something like 64C (64 x lightspeed, not Centigrade). I don't know if he made that up on the spot or if he obtained info from Roddenberry.

But that's why starships have deflector arrays. To deflect any matter in their path.

IIRC, the original "warp factor" was a square of "c." Somewhere down the road, they decided that wasn't fast enough to get around the neighborhood and bumped it to a cube of "c." Then there was some funky hand-waving and they tacked on a exponential scale onto the warp 9's to equate warp 10 with "infinitely fast."

I'm sure I'm screwing something up but that's what I remember.

[ruckeriii]

Originally Posted by ChunkyC

Personally, I don't know if gravity-based technology will ever be invented, because we still don't know if gravity is actually a force. One theory I've read is that space itself is deformed by objects with mass. For a crude analogy, think of a bowling ball on a trampoline. It bends the flat surface of the trampoline downward. Roll a marble around the bowling ball and it will change course and pick up speed as it gets closer.

Actually gravity can be tested and altered. For instance a large salt deposit will weaken the pull of gravity. This is one of the ways to find oil, large oil deposit are often covered by large salt sheets for some reason so you look for areas where the gravity is weaker. Now it is up to the eggheads to find out how salt dos this.

Mason

[rmgil04]

Originally Posted by ChunkyC

Hey, got a ? for ya ... if Star Wars uses repulsors, that means they push, right? So in the case of the big troop carriers in the Phantom Menace, they must push against the ground. Those things must weigh tons, so the amount of repulsive force must be enormous to keep them a foot or two off the ground.

So how come Qui-Gon and Jar-Jar weren't mashed to jelly by the force of the repulsors when that troop carrier drove over them?

Inquiring minds wanna know!

Well if we're gonna get into Star Wars bashing, count me in. I've seen some great shows on History Channel, and Discovery that discussed flaws in Star Wars tech.

However, none of them got to my biggest pet peeve over Episodes I-III vs IV-VI.
How much time passes between episodes IV - VI? My understanding is just a few years, but Luke becomes a Jedi in that time. 10 years passes between Episodes I and II, but Anakin is still a Padawan even though he was being trained constantly in the Jedi temple.

[Lhun]

Night of the living thread?