radioisotope
RAY-dee-oh-EYE-suh-tope
Definition
A radioactive variant of a chemical element that is unstable and emits energy as it decays.
Etymology
The word is a combination of 'radio-' (from 'radioactive') and 'isotope' (from the Greek 'isos', meaning 'equal', and 'topos', meaning 'place'). It refers to variants of an element that occupy the same place in the periodic table but have different atomic masses.
In the news
The article uses the term to describe the power source of the Voyager probes, which convert heat from decaying plutonium-238 into electrical energy. This technology allows the spacecraft to remain powered long after they have traveled beyond the reach of sunlight.
NASA engineers working to extend the Voyager missions cannot physically touch the spacecraft, cannot send a replacement part, and must wait nearly 24 hours for every command to arrive — and another 24 hours for the reply — yet they just bought Voyager
Read the full article ↗Space Daily