"Noble gases" refers to a group of elements in the periodic table that are very stable and do not easily react with other elements. They are referred to as "noble" because they have a dignified and unreactive nature. Full definition
These findings enable the study of individually confined noble gas atoms using surface science methods, opening up new opportunities for fundamental research. (nature.com)
They have looked to indirect evidence, such as seismic data and noble gas transport. (scientificamerican.com)