[tired&retired]

I wonder if this is how I feel density differences several feet from my hands...

I’ve used this ability in the past when screwing drywall to the studs. I just move my open hand and I feel the stud location behind the drywall.

It also works on brain tumor locations....

I read about this technology several years ago in Japanese research. They were using it to determine contents of rooms in the pyramids. Kind of like an energy ultrasound.

[Red Badger]

The simplest explanation is Temperature Differential.

The human skin can detect temperature differences of 0.1°F.

You feel the wall and the temperature of where the stud is versus where the empty air space is detected by your hand as a location device.....................

[Windflier]

I’ve used this ability in the past when screwing drywall to the studs. I just move my open hand and I feel the stud location behind the drywall.

I believe you. I've experienced similar kinds of heightened perception now and again in life.