LW: Why would humans use klicks to talk about distance?

[Rick]

But 0.8 AU doesn't convey the feel of "12million klicks". It might be used in reality but in a work of fiction one of the things that the author has to do is communicate with us and for most of us 0.08AU is something we'd need think about which rips us out of the narrative.

[Ulmer Ian]

P. Aaron wrote: "Saying an asteroid is .08 AU away just takes less time than saying it's 11,967,840 kilometers. "

But I would prefer 12 gigameters over .08 AU. :)

distance from earth to the sun is such a weird unit of measure anyways, since it changes all year round. I guess it means average.

[Tim]

12 million klicks works for me - much easier to conceptualise. :)

Someone on the previous page mentioned a Yottametre. I can't help thinking that would get abbreviated. I rather like the idea of a "Yo-Klick"....

[Robert]

There are really two problems ... what would the reader call such a distance, which is hard because we don't normally deal with millions of kilometers, and what would the people IN the book call it.

A league is about how far you can walk in an hour on poor roads. If it was routine to travel within the solar system and at speeds that make it practical we would invent a new, mores useful unit for about an hour of that type of travel; a unit of measure that would give reasonable numbers as kilometers do now for driving and walking.

[Richard]

I think as soon as man ventures into space properly we will probably use the light second and minute, because as said earlier it would act as a way of measuring both distance and give an idea of how long it would take to receive a reply from any communications made.

I liked the idea of using the AU, but in the context of the book I don't think belters would like routinely using a unit of measurement that was based on the Earth, even if it is deeply routed into society from hundreds of years of use.

[terpkristin]

The podcast this week got me confused about clicks again. Stackpole, talking about something else, said something like "one and a half klicks away and an automatic weapon" or something like that...which made no sense. You're not shooting anything from 1.5 klicks...

[Joseph]

terpkristin wrote: "The podcast this week got me confused about clicks again. Stackpole, talking about something else, said something like "one and a half klicks away and an automatic weapon" or something like that......"

Well, that's 1500 meters, so I suppose it depends on the weapon. Or he was just talking off-the-cuff and grabbed a distance out of the air.

[Tamahome]

One of these puppies can do it.

http://en.wikipedia.org/wiki/Accuracy...

[AndrewP]

terpkristin wrote: "Stackpole, talking about something else, said something like "one and a half klicks away and an automatic weapon" or something like that...which made no sense. You're not shooting anything from 1.5 klicks... "

Records for sniper kills are significantly more than 1.5k. See here:
http://en.wikipedia.org/wiki/Longest_...
The current record is almost 1 km further.

[terpkristin]

Wow. I guess that shows how little I know of modern weaponry and capabilities. I was figuring the max distance would be on the order of 500m or so.

Wow.

[Christopher]

Another thing to keep in mind is that distances need to be related to velocities easily.
You don't measure your car's speed in feet per second when your trip length is measured in miles.
Conversely you don't want to measure your distances in AU or fractional LY if you are traveling on the scale (and measuring on the scale) of km/h or km/s.

[Ulmer Ian]

Christopher wrote: "Conversely you don't want to measure your distances in AU or fractional LY if you are traveling on the scale (and measuring on the scale) of km/h or km/s."

well no need for fractional LY, just use LS which I guess is pretty practical for solar system distance. And unlike LY it's independent something wobbly like the revolution of Earth, LS I guess is already defined by basic physics measurements.

gigameters sounds cool, but I admit that LS probably makes the most sense. In Caliban's War there's a character who essentially is addicted to the Internet and certainly measures distance by the light latency.

[Christopher]

When light latency is important it certainly makes sense to measure distances that way, or when you are trying to show the scale of very long distance.
However, when you are measuring travel distances you want to measure distance in the same type of units as you are using to measure velocity. Since velocity is distance per unit time, in order to estimate travel time you must either measure your distance in the same units or convert. People who travel a lot aren't going to want to spend a lot of time converting units unnecessarily.
So unless my ore hauler, or whatever, measures velocity in LS per unit time, I don't want to see distances measured that way. Besides, unless you have two "speedometers" you will still need something for what might be called docking speeds, more like meters per second or slower.

By the way, light seconds ARE fractional light years, since a second is a fraction of a year.

[Joseph]

Ulmer Ian wrote: "yea parsecs are annoying... I always have to look up what they mean. And really don't make much sense for interstellar travelers to use, they only make sense for astronomers."

I've always kind of liked the parsec, but that probably dates back to buying way too many Traveller supplements back in the 1980's.

[Dwayne]

Ulmer Ian wrote: "yea parsecs are annoying... I always have to look up what they mean. And really don't make much sense for interstellar travelers to use, they only make sense for astronomers."

The definition of a parsec can be confusing, definitely. Obviously since the book deals with distances within the solar system, it kinda goes without saying the parsec is a useless measurement in this context. But if you're at all curious about what the term actually means it is essentially a measurement of an apparent parallax shift of one arcsecond. If you understand the idea behind parallax, this should be easy, but if you've forgotten, it's the apparent shift an object makes between two advantage points (your left and right eyes being the most common example of introducing this apparent movement.) Just hold your finger up close and switch viewing between your left and right eyes - (think camera one, camera two from Wayne's World :P ) and the finger appears to 'jump' a short distance. Of course the further away your finger is, the less apparent this jump becomes.

So needless to say stars being as far as they are, this shift of apparent motion between seeing a star from Earth (say on December 21st) and seeing the same star again about six months later (say June 21st) is minuscule. Now a degree of apparent size is about the width of your pinky held at arms length. If you see a person from far away, and can block them perfectly with your pinky (again, your arm would have to be stretched out completely with elbow locked), then you can say that person is a degree in apparent height. That person is also 60 arcminutes in height, or 3600 arcseconds. So an arcsecond is very small. If we divided our one degree high person into 3600 pieces, and found a star that shifted a distance equal to one of those pieces in six months time then that star would be a parsec away. Since the nearest star is about 4.2 light years away (Proxima Centauri), it actually travels a little less than an arc second's worth of parallax - about 769/1000 of an arc second because it's a little further than the 3.26 light years that defines a parsec. But the parsec is a good 'meter stick' for astronomers besides the light year itself.

Hope you found this illuminating (okay, that was just a bad pun.)

[Christopher]

Another interesting thing to think about is that, as the book says, acceleration is a very important part of travel. At the velocities we travel on earth acceleration is just mashing on the throttle, and gravity+friction slows us down, and lets us change direction, mostly.
In space you are going to burn fuel/throttle up to accelerate. And by accelerate I mean any change in velocity. "speed up", "slow down", or change direction.
So you have a burn -> coast -> burn thing going on, not really a constant burn of fuel. So unless the coast (constant velocity) part is the majority of the trip, estimating the time of the trip becomes less about distance and more about periods of acceleration.
eh?
So so wouldn't necessarily need a new "space klick", but we would probably end up with a new way of talking about travel altogether.