Think about this!
Space objects emit energy in the radio, microwave, infrared, and visible regions of the electromagnetic spectrum. The electromagnetic spectrum (shown below) encompasses the range of all electromagnetic waves. Our eyes operate in the visible region of the spectrum, allowing us to see space objects such as stars! The visible region, however, is a very small part of the spectrum. Stars, gases, and dust clouds in space emit radio waves, while galaxies in space emit microwaves, and infared light is emitted by dust between stars in space. The spectrum on the left shows some of the uses of each of the different kinds of electromagnetic waves, while the spectrum on the right shows the relative size of the waves by comparing them to different things.