Would an ordinary compass work on any planet? Would there conceivably be a compass specific to a specific planet?

I'm sure every planet generates a magnetic field of some sort, but I'm not sure what the rules are about how that field is oriented. As you no doubt know, even Earth's magnetic field does not place magnetic north directly on the north pole. And science suggests that the Earth's magnetic field has reversed several times. not sure how long it takes tho.

So yes, if you used a compass on another planet, it would most likely work, but it also would most likely NOT point north, or south or any any terribly useful direction. Until, that is, you figured out where magnetic 'north' was on the planet. Once you figure that out, it would make navigation a bit easier.

Hope that helps a little.

But not every planet has the same orientation - Uranus rotates on its side, but its field direction is offset about 60 degrees [roughly - relying on memory here]. But not all plnaets have a magnetic field either - can't remember which one - possibly mercury. Try researching if you want proper answers

You wouldn't need to build different compasses for different planets where the field is aligned at least along similar orientation - for example, a compass for earth would work just as effectively for most planets in our solar system [though the tug from Jupiter may damage the needle!].

Perhaps a need for a different compass design would be where the field is specifically aligned at obtuse angles - such as 90 degrees from the plane of rotation. So one solution would probably be to have the usual needle hidden behind the display face, with a different needle, offset ot the correct angle [ie, 90 degrees here], on the facing display.

As for metals not found on earth - this is a definite danger area - unless you're going to start playing with the mechanics of nuclear physics, or else be happy to disregard them [which may lose you readers, unless you're aiming at juveniles].

If you're trying to keep to physical realism, then there's a hint that there are islands of stability at the end of the periodic table - atomic number 112 I think I remember being one such island [but stable meaning existing for approx 10x 10-8 seconds, or so].

Now, if you were to postulate the existence of a stable element with an atomic number around there, then what you could potentially have is a material that would be heavier than lead, but stronger than steel.

[I've been told that UFO lore has it that "the Greys" use element 115 as a fuel source].

In fact, thinking about it, if you really wanted an equivalent to Tolkien's Mithril [excluding its mass! - unless you mess with the density] then islands of stability at the end of the periodic table would be the ideal place to mix speculative fiction with fantasy realism in discovering new metallic elements with unqiue and useful properties.

Hmm...bit of a ramble.

Damn, I'm definetly a writer, the orginal post and two replies and I had a hundred different ideas how that could kick ass.

JOHN!!

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Am I understanding correctly that only books with no GENERAL market appeal are considered "true" sci-fi--that anything that is not "a riddle wrapped in a mystery inside an enigma" {Churchill}is a poor relation?

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As for metals not found on earth - this is a definite danger area - unless you're going to start playing with the mechanics of nuclear physics, or else be happy to disregard them [which may lose you readers, unless you're aiming at juveniles].

If you're trying to keep to physical realism

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Isn't this the closing of the big tent I asked about? If science fiction is all about "keeping to physical realism," then it's hardly the stuff of imagination it can be. I had the impression that suspension of reality was the name of the game. Otherwise, only science experts need apply.

If anything less than that is "juvenile," then maybe that's what I called "general market appeal."

I know I'm not into dark and convoluted sci-fi and I am going to guess the general public isn't, either. If there are spaceships taking off and landing right next to houses, I will happily assume--and I don't need to know the scientific explanation, or even to know that it's really quite impossible--that the afterburn has somehow been tamed.

Earth to sci-fi purists: Many of us are not looking for "physical realism." Why isn't there room for all of us? Besides, insofar as we have not explored much of the universe, why wouldn't strange metals be possible? Why define the universe within our own narrow parameters?

How is that any different than believing in white dragons that fly "between?" Or in aliens of any sort?

I go back to my original thought: It seems to me sci-fi rules are written as a caste system.

There is an audience for all of it.

I get the impression that you are more interested in the “It just works” end. I hedge more in that direction myself. I don’t object to reading “hard Sci-Fi” now and then out of variety, although I don’t think I’m too interested in writing that way. But things have to be grounded in some sort of consistent reality or there is chaos.

So here is one argument for looking at the compass situation from a physical realism perspective. You might have problems just doping up a planet with metal not found on Earth because there is a large body of the general public who is familiar with our planet and solar system, and certainly with how a compass works. Other rules of physical science are applying I assume. Where is the line drawn? You risk that they aren’t going to buy into the idea of it working differently because they know it isn’t true. Then you’ve lost your credibility, which may or may not kill the story for them.

It’s a bit different than dragons going “between.” There is no real-life parallel to that one. In that case people will believe whatever you define the rules to be because there is no other definition (more on this below).

But if you bend the rules just a little bit, the reader could bend along with you. Maybe a rare Earth metal or isotope is at an unusually high level on the planet. Maybe a scanner, not a compass, that works on something other than magnetism. The hint of reality is the hook to make they take the entire bait of the (and I’m just guessing here) more fantastic things that they are going to find on this planet.

Either that or you need to branch away from the known rules far enough so that it loses the real-life parallels, and so then all new rules can be applied.

All that said, really, if you’re going more for space-situated fantasy, go the full distance, hand-wave the technology, and run with what makes the story works. Because then you aren’t trying for something that will fit into our known reality. It’s something different. Give it it’s own rules, and then stick to them to make it its own version of reality.

That’s a place that weird metals can live quite happily.

It really all just depends on what sort of backdrop you are trying to use.

I like to think sci-fi is a spectrum, too. I've read and enjoyed Asimov, Dune, Farenheit 450 (am I remembering the title right?), Ringworld, three or four White Dragon books, and others. But I keep bumping into comments insinuating that if sci-fi isn't die-hard accurate scientifically speaking, it isn't true science fiction.

I can relate to John and his 100 ideas about the compass possibilities.

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You might have problems just doping up a planet with metal not found on Earth because there is a large body of the general public who is familiar with our planet and solar system, and certainly with how a compass works.

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I guess some erroneous assumptions have been made. I'm not planning to use odd compasses on planets in our solar system. I'm thinking strictly about planets that have been birthed in my own mind, planets that do have strange metals.

But if it's possible for an odd compass to work on different planets, even in our solar system, then even the fantasy becomes more believable. Hence, my question.

[This message has been edited by Kolona (edited June 27, 2002).]

Ultimately, all literature is about recreating reality - and sci-fi and fantasy genres specifically seek to extend the bounds beyond the norm.

The future is a mystery - without detailed precognition no writer can know what scientific advances or technologies may exist in the future. This is both the strength and weakness of sci-fi.

The strength is that it allows the imagination to be unbounded - but the weakness is that the reality created can be made irrelevant by continuing advances in human thought, and thus easily become "dated".

It is also for this reason that "realistic puritism" rests on its own shaky foundations with science fiction - precisely because those future constructs are unknown.

Using scientific thinking as a guide to the structure of the reality of a writer's making can provide excellent reference points, and help establish a sense of reality for a reader - in short, make the experience more believable.

But it is a device, nothing more, and one to be wielded carefully. Good storytelling is simply good storytelling, and will use many devices. Attempting realism is simply one option.

Ultimately, science-fantasy is bounded only by imagination. And there are no rules on that.

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But I keep bumping into comments insinuating that if sci-fi isn't die-hard accurate scientifically speaking, it isn't true science fiction.

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Oh I know. I’ve heard it too. Some people are very adamant about that fact.

But this was fun.

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Ultimately, science-fantasy is bounded only by imagination. And there are no rules on that.

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That's where I live. Thanks, CofE.

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Fahrenheit 451 Good book, though the concept made me sick when I read it.

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Didn't it, though? I read that when I was a teen and it really made an impression on me, as it should on any reader, I would think.

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But people live in the tents the size they want to make them.

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...or the shape, or the color, or location on the planet of their choice...

Sailing ships might have had compasses that were heavy enough, but I think they tended to be bolted down.

So maybe some other kind of blunt object would serve better.

The compass had been included in a purchase of survival gear prior to setting out, since the terrain between the departure and destination points is decidedly unfriendly. A subsequent crash landing dislodges the compass from its clip and it makes contact with said head.

Whether one would work or not on an alien planet, I find it hard to believe that a hit in the head by a compass would do much damage.

You might envision a magnetic field produced externally . . . a compass on Jupiter's moon Europa, for example, might show you what direction you are facing relative to Jupiter, not Europa.

You might get something cool if you put a planet around a star with a stron magnetic field. "North" would move around, based on the time of year. Seasoned navigators would know how to account for this, but beginninr could be easily lost.

(I raised my kids(17 years) in Garfield Hts., Doc. I miss Ohio.)

After Kathleen's post, I checked around & lit upon "Howstuffworks" among others (CofE would be so proud of me),& discovered the gyrocompasses, too--also a gyrosyn compass for aircraft that is a magnetic compass stabilized by a gyroscope.

I gather the gyrocompasses are electro--(electric, electronic, electromagnetic?)--which means they need a power source?? In which case they couldn't convert to hand-held--for too long a time at any rate??

Also read they have to be periodically verified against a magnetic compass, so it sounds like a shuttle would need both?? Gyrosyns sound like they have both to start. (I'm not sure where that gets me, since the survival gear would surely have hand-helds. I don't know where I'm going with this.)

Anyroad, I had envisioned a compass similar to the ones on the dashboard of cars, set in a bracket/clip and interchangable if planet-specific ones were needed. They weigh in at about 10 ounces, so I thought that would create a good enough bonk under the circumstances, & if squared at the base, could draw some blood, too.

It seemed to me that too much miniaturization might not be beneficial with a dash/console-mounted compass, so I figured I was safe there, unlike GPS--which I had considered.

Having a friend who has a GPS, I thought that miniaturization would be more compatible with it and its bonking capacity might then be a problem--although in a crash landing, wouldn't a lot of otherwise innocuous items develop sinister bonking capabilities?

However, I figured redudancy might be important to space travelers since, as in this case, the transport ship is also on the ground. (My understanding is GPS is strictly space/satellite-based.)

I do love that stron magnetic field. What a riot that could be.

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You’ve got your “This could happen next year and here are 5 papers in field appropriate peer reviewed journals to back me up” on one end with “Here’s some technology that works because I said it does” on the other.

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It's interesting you put it that way...

Theoretically, you don't need a huge gyroscope for a gyroscopic compass. Given a culture with nanotechnology, I could see a pretty accurate one running for a year on a AA battery. But (I believe) it would NOT work in space. I think gyrocompasses work by the rotation of the planet. If you change latitude you probably need to account for it, so if you want that to be automatic you probably need the GOS system anyway.

Magnetic compasses point to the planet's magnetic poles. Geographically, it is possible for these to change over time.

Edit: I live just a few miles from Garfield Heights. I was born there.

It may even be desirable on a strange planet so characters wouldn't have to do adjustment calculations as they would if reading a normal compass.

It may even be necessary if planet has strange metals, which is also possible.

So it could be the object that collides with my character's head and could conceivably cause loss of consciousness and draw some blood, depending on size, shape, and crash specifics, and I guess the term "freak accident" could enter in and cover a multitude of sins even for the purists among us.

'Course, I could just make up a whole new guidance tool/system and really take a chance. Naw.

That could lead to a humorous scene, if an inexperienced explorer consulted a gyroscope, only to discover that west had become straight up!

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You don't need the mothership in orbit to have GPS. You only need it to deposit a bunch of tiny satellites before landing. I'd expect any mission that knows it's going to be finding its way on an alien planet to use equipment like that, if not more sophistocated.

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I know you mentioned the satellites before and that's an interesting idea.

Two possible problems:

1.) They didn't know they'd be trekking across the planet. And if they had been inclined to launch the satellites as a precaution, they still might not have because

2.) they were somewhat intent on avoiding being tracked, and I'd imagine leaving tiny satellites might constitute proof they had been there. Yes, they could have somehow collected the satellites when leaving but, again being cautious, might have anticipated the possiblility of leaving in a less orthodox manner than in the same ship in which they arrived--which is what happens.

However, would any satellite work for GPS? If the outposts on the planet already had one/some in orbit, would they be sufficient for anyone's use as regards GPS?

Boy, if spaceships are always leaving tiny satellites in orbit around planets--space littering--wouldn't that be a danger to other vessels?

- thermos flask
- first aid kit
- ship's cat
- ship's monkey
- fluffy dice
- cheeseburger
- alien egg
- alien
- penny jar
- weekly shopping
- Arthur C. Clarke
- leftover sausage roll
- matchsick model of Mount Rushmore
- laundary bag
- "Astronaut's Companion" blow-up doll
- Jell-O
- TV set
- GPS satellite
- plastic Godzilla
- instruction manual for flying spaceship

Maybe I'll chance publication without indicating how these intrepid space travelers oriented themselves--or is that orienteered? I think there may be something to be said here for assumptions. Let the disgruntled purists write me and complain.