How does James Webb telescope work? What will it see?

The atoms in our bodies were forged deep within the bellies of red giant stars eons ago. And if we peer deep enough into the night sky, we can see stars just like them taking shape at the edge of the observable universe. The light from those stars is more than 13 billion years old and thanks to the expansion of the universe, it has stretched out into super-long infrared wavelengths—basically heat. To “see” that heat, you need a really big, and really complex telescope. In space.