Why do we need to use telescopes that are sensitive to other types of radiation

Astronomers use the variety of telescopes which are sensitive to different parts of electromagnetic spectrum. So they have different telescopes or detectors for each band of the spectrum. In order to study the objects in space they study it through various portions of EM waves. Here we take an example of the microwaves. Our earth's atmosphere block most of the microwaves. So Scientists use the telescopes on satellites to study these cosmic waves. Microwaves are the remains of big bang so by studying them we can describe the beginning of universe.