Carbon nanotubes are the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively. This strength results from the covalent sp 2 bonds formed between the individual carbon atoms. In 2000, a multi-walled carbon nanotube was tested to have a tensile strength of 63 gigapascals (9,100,000 psi).  (For illustration, this translates into the ability to endure tension of a weight equivalent to 6,422 kilograms-force (62,980 N; 14,160 lbf) on a cable with cross-section of 1 square millimetre ( sq in).) Further studies, such as one conducted in 2008, revealed that individual CNT shells have strengths of up to ≈100 gigapascals (15,000,000 psi), which is in agreement with quantum/atomistic models.  Since carbon nanotubes have a low density for a solid of to g/cm 3 ,  its specific strength of up to 48,000 kN·m·kg −1 is the best of known materials, compared to high-carbon steel's 154 kN·m·kg −1 .
A distinction should be made between electromagnetic sensitivity, and symptoms an individual labels as such. Researchers have failed in proving that those claiming sensitivity to electromagnetism can accurately determine the presence of a strong electromagnetic field. Nevertheless, the perceived symptoms are real for the patient, and should be honored as such, or until it can be demonstrated that they are psychosomatic or have some other physical source. Many people who meditate, for example, perceive energy movements in their body and learn to work with these. But a second distinction must be made between those who successfully work with unusual psychological states and these who find them debilitating. For the later, either drugs or meditative practice may or may not be helpful. Overcoming, defusing, or sublimating debilitating mental states is never easy.