Answer: The infrared radiations can detect the coolest and dimmest space objects.
In general, the coolest and darkest regions of space emit radiations of longer wavelengths. The Infrared telescope is used to find the cool, dim stars by slicing the interstellar dust bands and also measure the temperature of the planet of the solar system. The coldest stars do not emit light so they can be seen with the infrared telescopes only. In the visible region, blue stars are hottest and red are the coolest. The wavelength is inversely proportional to the energy emitted so the hottest stars are in the region of low wavelength in visible region.