Yes. This particular line is the spin flip transition: https://en.wikipedia.org/wiki/Hydrogen_line https://en.wikipedia.org/wiki/Hydrogen_line and is low enough

Yes. This particular line is the spin flip transition: https://en.wikipedia.org/wiki/Hydrogen_line https://en.wikipedia.org/wiki/Hydrogen_line and is low enough energy that cool clouds of molecular hydrogen emit it. And that's why radio astronomers frequently observe at this frequency.