Herschel has been designed to observe the `cool universe'; it is observing the structure formation in the early universe, resolving the far infrared cosmic background, revealing cosmologically evolving AGN/starburst symbiosis and galaxy evolution at the epochs when most stars in the universe were formed, unveiling the physics and chemistry of the interstellar medium and its molecular clouds, the wombs of the stars, and unravelling the mechanisms governing the formation of and evolution of stars and their planetary systems, including our own solar system, putting it into context. In short, Herschel is opening a new window to study how the universe has evolved to become the universe we see today, and how our star the sun, our planet the earth, and we ourselves fit in.
The European Space Agency's Herschel Space Observatory (formerly called Far Infrared and Sub-millimetre Telescope or FIRST) has the largest single mirror ever built for a space telescope. At 3.5-metres in diameter the mirror will collect long-wavelength radiation from some of the coldest and most distant objects in the Universe. In addition, Herschel is the only space observatory to cover a spectral range from the far infrared to sub-millimetre.