BP said:
As MGT Densitometers 'can determine the internal structure and makeup of an object' at distances upto 10 km, I figured they would need to be based on something more exotic - i.e. graviton detection or Higgs field handwaviums... but, haven't found a MGT source that would collaborate this.
Well, sensors have to work in one of several ways:
- by detecting something that an object is itself emitting (passive sensing).
- by something passing through an object that affects it, and detecting those changes (generally passive sensing again, unless you deliberately set up whatever is on the other side emitting the radiation or whatever).
- by firing off a pulse of something that the object then absorbs/reflects/scatters/whatever, and detecting whatever comes back to the sensor (active sensing).
A medical X-ray, IIRC, is (or used to be) passing X-rays through organic material to affect a film on the other side of the target - more absorptive objects (like bones) would show up as brighter, less absorptive objects would show up darker.
A densitometer (as described in MGT) can't work the same way. Even if you say it's graviton detection or whatever, you're still receiving all the gravitons (or whatever) at the sensor at the same time - so how can you tell the ones that are emitted by the mass of material in an interior wall, or how can you tell that there's an empty space inside the object?
I could see how one could use a densitometer to figure out the overall mass of a target, and (given other EM measurements detecting its shape and therefore its volume) its bulk density, but internal structure? I think you'd need something more sophisticated to do that - like something that launched an array of probes at the object that really could map it out in 3 dimensions by taking readings from many different points at the same time.