Laser visibility

[gchuck]

I've always assumed that laser rifle/carbine/pistol beams are either IR/UV light, and therefore invisible to the human, and some sophont eyes.

Is it reasonable to expect some sort of 'bloom', or other 'after-image' effect when in the vicinity of said weapons fire?

PC's were within 10m of an assassination, and rapidly figured out the weapon type with no visual clues.

chuck

 

[Spinward Flow]

Is it reasonable to expect some sort of 'bloom', or other 'after-image' effect when in the vicinity of said weapons fire?

PC's were within 10m of an assassination, and rapidly figured out the weapon type with no visual clues.

They may not have "seen" the laser shot ... but at less than 10m away they would have HEARD the damaging effects of the laser shot.

Even if the laser sniped from a long way away (so there's no "trigger pull" noise for them to hear) ... on the receiving end if that laser damaged flesh there would be a distinctive vaporization/cauterization "steam explosion" where water laden flesh is very suddenly raised in temperature past the supersaturation point and violently explodes as the water in the flesh transitions from solid/liquid into being gas/plasma due to thermal shock.

In other words, lasers would inflict characteristic wounding effects that would be readily recognizable as being caused by a laser.

If the PCs were in an enclosed room and no windows were broken by a bullet, that would be another clue that a laser was used.

So being able to make that determination with no visual clues is possible, and also a likely assumption given the right audio clues at that proximity. Those audio clues won't necessarily "work like a tracer" to point back at the shooter (so low signature upon firing still makes sense), but an experienced infantryman/security type would very quickly recognize a wounding effect dealt by a laser weapon.

I've always assumed that laser rifle/carbine/pistol beams are either IR/UV light, and therefore invisible to the human, and some sophont eyes.

Up through TL=12 in CT, lasers can be anything in the IR, optical or UV spectrum ranges.
At TL=13, laser rifles/carbines/pistols are made as X-ray lasers, which is why they get a deadliness/damage bump at TL=13+ in CT.

 

[agorski]

Depends on the medium it's firing through. Maybe high humidity in atmosphere is enough to make it visible.

 

[Spinward Flow]

Depends on the medium it's firing through. Maybe high humidity in atmosphere is enough to make it visible.

If the laser isn't tuned to the optical band, the only thing that might make it detectable to the eye would be a "hole in the air" where all the suspended moisture/dust got "burned away" by the laser en route to target. However, that would be such a transient effect that you would need to be rolling the equivalent of a critical success in order to notice it in anything other than the most favorable of conditions.

The way @gchuck was talking about the situation didn't sound like the assassination took place during a foggy walk.

 

[Condottiere]

I thought while toasting, you can detect the beam through the red wine in the transparent wine glass.

 

[Blue Ghost]

I've always assumed that laser rifle/carbine/pistol beams are either IR/UV light, and therefore invisible to the human, and some sophont eyes.

Is it reasonable to expect some sort of 'bloom', or other 'after-image' effect when in the vicinity of said weapons fire?

PC's were within 10m of an assassination, and rapidly figured out the weapon type with no visual clues.

chuck

It depends on your game. In the real world LASER glints off of medium that can reflect or refract, hence when you see LASER experiments demonstrated the scientist usually sprays some mist or even "dust" in the LASER's path so that you can see it.

Cinematically LASERs are always visible. And even scientifically accurate lasers diffract somewhat. That is at a certain angle you actually the LASER beam.

Just my two bits.

 

[aramis]

I've always assumed that laser rifle/carbine/pistol beams are either IR/UV light, and therefore invisible to the human, and some sophont eyes.

Is it reasonable to expect some sort of 'bloom', or other 'after-image' effect when in the vicinity of said weapons fire?

PC's were within 10m of an assassination, and rapidly figured out the weapon type with no visual clues.

chuck

THere will be audible noise in many atmospheres, and a bit of low-light visible heating to emission of atmosphere.

The laser itself won't be visible if it's IR or UV, but the heating of the air and particles suspended in it may result in heating to glow, and may result in expansion of the atmospheric medium from said heating. Pump enough in, it becomes noticeable as a plasma channel.

Laser Tasers work on that very set of principles - you ionize the air with the laser, and use the ionized channels as your virtual wires to the target.

 

[whartung]

Even if the laser sniped from a long way away (so there's no "trigger pull" noise for them to hear) ... on the receiving end if that laser damaged flesh there would be a distinctive vaporization/cauterization "steam explosion" where water laden flesh is very suddenly raised in temperature past the supersaturation point and violently explodes as the water in the flesh transitions from solid/liquid into being gas/plasma due to thermal shock.

Plus the screaming. Don't forget the screaming.

 

[Grav_Moped]

Plus the screaming. Don't forget the screaming.

And the Foley work. Someone's out there whacking a wrench against a telephone pole guy-wire to make those nifty blaster sounds.

 

[Nathan Brazil]

In Traveller 5, others may see the laser beams just fine. In generating new sophonts, the portion of EM spectrum a sophont "sees" is determined by the star they evolved under. Evolving, not merely born, under stars B0-F6 allows a sophont to perceive some portions of the UV range of frequencies. A sophont evolving under stars K4 and dimmer (L9+ brown dwarfs!) can see some portion of the infrared range of frequencies...

Of course, the likelihood of a native sophont species evolving under such stars is up to IYTU. IMTU, I am thinking maybe those humans transplanted by the Ancients might have had their visual spectrum shift over one or more bands over the last ~300,000 years, if the star is sufficiently different from our evolution with Red, Green, Blue (the centerpoint of G2-K0 stars).

If you have T5 refer to
Book 1 "An Overview of Color" on page 191 and
Book 3 "Sophont Creation > 10 B" for Band ranges. Keep in mind you are rolling for vision Constant, not for the Bands, those are fixed.

 

[whartung]

Someone's out there whacking a wrench against a telephone pole guy-wire to make those nifty blaster sounds.

I remember seeing that way back in the late '70s, watching a show on ABC (I think) about Star Wars.

In Traveller 5, others may see the laser beams just fine.

It depends on the duration of the pulse also. It's (probably) not like those scenes with the laser pointers representing rifles, long beams dancing through the dust. It's going to be a aim, pull the trigger, and a very quick pulse of high laser energy. 10-100 milliseconds. It may simply too fast to register on a sophonts eye, even if they can see the light spectrum. Now, if you're in the front line hundreds of participants firing thousands of shots, you may certainly catch a glimmer here or there, but not necessarily any particular shot.

 

[kilemall]

Don’t forget goggles/helmet eye protection, which likely will have a display element rendering the lasers visible with an imaging overlay option.

 

[mike wightman]

The fundamental fact remains you can not see the laser beam at all unless it reflects/scatters off something. You can use thermal imaging to see the path of hot air in the absence of particulates.

 

[Nathan Brazil]

It depends on the duration of the pulse also. It's (probably) not like those scenes with the laser pointers representing rifles, long beams dancing through the dust. It's going to be a aim, pull the trigger, and a very quick pulse of high laser energy. 10-100 milliseconds. It may simply too fast to register on a sophonts eye..

Yes quite possibly. Standard humans are outta luck. My thing was It is simply that the alien sensor the eye) detecting the correct wavelength means one less impediment for them. Our eyes register input at 60fps IIRC (16 milliseconds). Some "fast" changes like lightning bolts last longer partly because the rods and cones in our eyes give the illusion of longer duration as they time to reset.