As the nebula throws off its outer layers of ionized gas, it reveals its characteristic blue interior, composed of hydrogen and oxygen that have not yet been expelled off by the nebula’s stellar wind.

Source: https://time.com/6513062/james-webb-telescope-best-photos-2023/

Fast radio bursts have a unique ability to detect this ionized matter.

Source: https://houstonianonline.com/scientists-observe-an-8-billion-year-old-radio-burst-and-confirm-that-mysterious-signals-allow-us-to-weigh-the-invisible-part-of-the-universe/

Look closely, and you'll spot that comets have two tails, one made of ionized gas and another of dust.

Source: https://phys.org/news/2023-02-curious-comet-rare-approach.html