Helium is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas.
Core Principles & Analysis
Helium was detected in the Sun's spectrum during an 1868 eclipse by Janssen and Lockyer, 27 years before William Ramsay found it on Earth in the uranium mineral cleveite.
It has the lowest boiling point of any element at 4.2 K, never solidifies at atmospheric pressure, and below 2.17 K becomes a superfluid that flows without viscosity.
Liquid helium cools the superconducting magnets in MRI scanners, and the gas lifts balloons and dilutes oxygen in deep-sea diving mixtures to prevent nitrogen narcosis.