From Slashdot: Sticky Tape Found To Emit Terahertz Radiation. Reading through the comments, this is more of an interesting curiosity than a practical discovery, but I find the explanation fascinating. Terahertz-range radiation can be used for imaging, like C-rays. Denser objects absorb more of the energy, so looking at the “shadow” from the other side of the object can show hidden weapons, etc. Unlike C-rays, though, terahertz-range radiation does not harm the body.