Meson Comm and SIN (from Scout) not much copp

[Klaus Kipling]

Both these systems have a major problem which makes them almost useless.

You need to be stationary to use one. Now, the comm does have some uses, but this makes the SIN sensor totally useless, at there is no such thing as 'stationary in space'.

Stationary in relation to what? The nearest planet, the star at the centre of a system, or any other body. You can only be 'stationary' in relation to some other celestial body, by either being in geo-stationary orbit, matching velocities to non-spinning bodies, or actually landing. And even then, you could only scan that particular object. Useless for doing general sweeps for neutrino sources, in other words.

The SIN becomes functional if you substitute 'stationary' for 'not changing velocity'.

For the meson comm, all the above applies. Only useful as a terrestrial land line, really. I can see it utilised by spec ops teams, maybe communicating with a ship in geo-stationary orbit orbit, but otherwise, you'd have to be already in communication in order to match speed and bearing (or velocity), so as to be stationary relative to each other, and that is probably too much hassle or even impossible under most circumstances. Be quicker to send a pinnace with a hard copy.

 

[lastbesthope]

The SIN becomes functional if you substitute 'stationary' for 'not changing velocity'.

Similar problem though, with reference to what fixed or moving point are you measuring your velocity?

LBH

 

[iainjcoleman]

The SIN becomes functional if you substitute 'stationary' for 'not changing velocity'.

Similar problem though, with reference to what fixed or moving point are you measuring your velocity?

LBH

No, it's no problem. Velocity is relative, but acceleration can be measured without reference to a fixed point.

For exampple, imagine sitting on a train with no windows. As long as it's moving at constant speed on straight, smooth tracks, you can't tell how fast you are going relative to the ground. But if it accelerates, brakes, or goes round a corner, you can detect the acceleration without having to look out of the window.

In physics, this distinction between inertial (non-accelerating) and non-inertial (accelerating) reference frames is absolutely fundamental.

 

[GamerDude]

No, it's no problem. Velocity is relative, but acceleration can be measured without reference to a fixed point.

Is what you're saying acceleration is akin to speed... a value with no direction and doesn't matter what axis the force generating the acceleration is on.

Because I found this on Wikipedia (http://en.wikipedia.org/wiki/Acceleration) as the opening paragraph to the article.

In physics, and more specifically kinematics, acceleration is the change in velocity over time.[1] Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, i.e. a line, acceleration is the rate at which something speeds up or slows down. However, as a vector quantity, acceleration is also the rate at which direction changes.[2][3] Acceleration has the dimensions L T−2. In SI units, acceleration is measured in metres per second squared (m/s2).

Don't get me wrong, I'm not a physicist, just the HS science nerd who also took one or two mandatory physics classes in college many years ago. I understand I have just enough knowledge to shoot my foot off in glorious blaze of expanding gasses (gunpowder going off).

 

[captainjack23]

Wow, this gets complicated fast.

I'd assume (and have done so) that the relative movement is between the two points in question, and needs to be zero; so, I'd say that one can either have two points with differences in velocity (and I presume, vector) equal to zero, or one could broadcast to where the target will be, and correct it for the duration of the communication.

Mesons communicators move in a straight line, ignore intervening matter and decay at a specific duration based on their speed -so one is essentially shooting at the target so as to decay in the receiver. Tricky, that.


Edit: Although I suppose they could have a small meson screen at the receiver end to force them to decay when they hit the target.....
hmmmm.

And keep in mind that these are the mysterious particles discovered by Professor Meson sometime in our future, not the ones we primitive screwheads call mesons nowadays..

 

[iainjcoleman]

No, it's no problem. Velocity is relative, but acceleration can be measured without reference to a fixed point.

Is what you're saying acceleration is akin to speed... a value with no direction and doesn't matter what axis the force generating the acceleration is on.

No, acceleration is a vector: ot has magnitude and direction. Think about when you're sitting in a car - you can feel whether you're accelerating forwards (speeding up), backwards (slowing down) or to the side (turning).

The point is that you can measure acceleration within a single reference frame, e.g. by measuring how hard you feel like you're being pushed into your seat when the car accelerates forwards. But you can only measure your velocity relative to some other reference frame, e.g. how fast the lamposts seem to be moving past the car as you drive down the street.

And I am a physicist (PhD in astrophysics, and eight years working in space physics research), if that helps.

 

[GamerDude]

That's what I thought I remembered from my classes, and what the quote from Wikipedia says.

Maybe I asked too nicely and goofed on getting my point across.

And I am a physicist (PhD in astrophysics, and eight years working in space physics research), if that helps.

Well yeah cool. I mean as long as you know what you're talking about the degree is gravy No disrepect to the degree.. after an AAS, 2 BS's and a Masters (all in the computer field) I opted to stop going to school even though I had an invitation from a university to get my PhD in the same field.

In fact, I LIKE when someone with the credentials gets in on a discussion, I just don't like it when they are a jerk about it, lord their "smarts" over everyone, expect what they say/believe/have figured out to be "the only answer" etc.

So thanks and please... educate on!

 

[Lord High Munchkin]

And I am a physicist (PhD in astrophysics, and eight years working in space physics research), if that helps.

You have done it now... letting the cat out of the bag. You'll get pestered now for all sorts of free 'Traveller'-related info!

 

[alex_greene]

Then there's the influence of gravity from local astronomical bodies, of course, causing acceleration both in terms of magnitude and change of vector. However, the question of whether or not something is "stationary" or "moving" when everything in the cosmos is moving relative to everything else is a moot point.

astronomers across the world, from the dawn of civilised society, have handled the constant rotation of the Earth about its axis and its movement about the Sun quite happily for many thousands of years. Perhaps the suggestion should be that the ship must not engage its drives, perhaps only its reaction thrusters at most, and it must maintain a lock on the area of sky being studied for anomalies, or upon the other meson transceiver - which of course must maintain a lock on theirs.

And of course, if it has to shut down its power plant to prevent neutrino interference from the fusion plant that means the ship must be running in Grey Mode - batteries and aux chemical power plant only.

 

[Rikki Tikki Traveller]

I'd assume (and have done so) that the relative movement is between the two points in question, and needs to be zero; so, I'd say that one can either have two points with differences in velocity (and I presume, vector) equal to zero, or one could broadcast to where the target will be, and correct it for the duration of the communication.

Mesons communicators move in a straight line, ignore intervening matter and decay at a specific duration based on their speed -so one is essentially shooting at the target so as to decay in the receiver. Tricky, that.

This is how I interpreted what the book meant as well. Motionless between Target and Source. THAT is your frame of reference.

 

[lastbesthope]

The SIN becomes functional if you substitute 'stationary' for 'not changing velocity'.

Similar problem though, with reference to what fixed or moving point are you measuring your velocity?

LBH

No, it's no problem. Velocity is relative, but acceleration can be measured without reference to a fixed point.

For exampple, imagine sitting on a train with no windows. As long as it's moving at constant speed on straight, smooth tracks, you can't tell how fast you are going relative to the ground. But if it accelerates, brakes, or goes round a corner, you can detect the acceleration without having to look out of the window.

In physics, this distinction between inertial (non-accelerating) and non-inertial (accelerating) reference frames is absolutely fundamental.

Oh indeed, you can detect acceleration without reference point, but to measure it you need a reference point, but since acc=dv/dt, and v requires a reference point to define it,acc requires a reference point to be defined with respect to just the same.

You can indeed fidge around it by altering your frame of reference, but it still has to be in there somewhere, the frame becomes the reference pont in effect.

LBH

 

[GamerDude]

and something people tend to forget is acceleration occurs on all three axis. Many systems, (like GURPS) simplify everything into a 2D system for ease of play, but it happens in three.

 

[BP]

Uhm... 4

 

[GamerDude]

Uhm... 4

4? X, Y, and Z (unless you include Time).. or am I missing something?

walks off tearing hair out.

 

[alex_greene]

Uhm... 4

4? X, Y, and Z (unless you include Time).. or am I missing something?

walks off tearing hair out.

No, you got it. Acceleration is the derivative of velocity with respect to the variable of time.

 

[Sturn]

Apple Pie!

I thought I would contribute to this topic and it was the only thing that came to mind.

I think the author of Scout was not thinking in any kind of technical terms and just meant the ship can't be traveling/moving when the device is used. I don't think he was thinking of relative velocity to a certain object, the true definition of acceleration instead of what a layman thinks it is, etc, etc, until a brain hemorrhage sets in:

The Snicker Doodle comes out of jump space at the edge of the empty frontier system to scan for the mysterious mini-black hole reported by the old scout.....

Chris: Let's head to the gas giant first to pick up some fuel before doing any exploring.

Referee: Ok you activate the MD. It will be about a 40 hour trip.

Bob: Let's turn on the SIN sensor to scan for any of those abnormalities the scout reported.

Referee: You have to stop to and power down to use your new SIN sensor.

Chris: Ok we come to a stop and power down the fusion plant.

Referee: Ok it takes approximately 20 minutes to do so. It will take about the same amount of time to power back up and get moving again.

Bob: Anything special?

Referee: The SIN sensor takes some time to get anything useful back. You activate the SIN sensor and wait for preliminary information. After about an hour you get some very strange collapsed matter readings.

Chris: What's so strange about it?

Referee: The gray dot on your SIN sensor seems to be extremely small....but it is strangely moving directly towards your ship at an alarming speed. It will arrive in approximately 10 minutes.

Bob: Power back up and let's get moving!

Chris: Didn't you say it would take about 20 minutes to get moving again?

GM: Yes (evil grin).

It works if you can turn off the right side of your brain for a bit.

 

[BP]

...It works if you can turn off the right side of your brain for a bit.

But how long does it take to turn it back on? :lol:

 

[GamerDude]

...It works if you can turn off the right side of your brain for a bit.

But how long does it take to turn it back on? :lol:

Is that under Windows 98, Windows XP, Windows Vista, or Mac OS X Snow Leopard?

 

[BP]

For me - probably more like Babbage...

 

[iainjcoleman]

Similar problem though, with reference to what fixed or moving point are you measuring your velocity?

LBH

No, it's no problem. Velocity is relative, but acceleration can be measured without reference to a fixed point.

For exampple, imagine sitting on a train with no windows. As long as it's moving at constant speed on straight, smooth tracks, you can't tell how fast you are going relative to the ground. But if it accelerates, brakes, or goes round a corner, you can detect the acceleration without having to look out of the window.

In physics, this distinction between inertial (non-accelerating) and non-inertial (accelerating) reference frames is absolutely fundamental.

Oh indeed, you can detect acceleration without reference point, but to measure it you need a reference point, but since acc=dv/dt, and v requires a reference point to define it,acc requires a reference point to be defined with respect to just the same.

You can indeed fidge around it by altering your frame of reference, but it still has to be in there somewhere, the frame becomes the reference pont in effect.

LBH

This is a bit confused. "Detecting" acceleration and "measuring" it are exactly the same thing.

As you say, a=dv/dt. Hence, velocity is the integral of acceleration with respect to time. Performing that integral will give you a velocity v plus a constant of integration k. The choice of k is the choice of inertial reference frame in which to measure the velocity.