MUSE will be an extraordinarily powerful integral field spectrograph fed by a new adaptive optics system on the VLT. In its usual operating mode, MUSE will, in a single observation, produce a 3-dimensional data cube consisting of 90,000 R~3000 spectra, each covering a full spectral octave (465-930 nm), and fully sampling a contiguous 1´x1´ arcmin^2 field with 0.2´x0.2´ arcsec^2 apertures. A high-resolution mode will increase the spatial sampling to 0.025 arcsec per pixel. MUSE is built around a novel arrangement of 24 identical spectrographs (each comparable to a 1st generation VLT instrument) which are fed by a set of 24 precision image slicers. MUSE is designed for extreme stability, with no moving parts, allowing very long exposures to be built up. Together with high throughput, this ensures that MUSE will have extreme sensitivity for observing faint objects.

Based on its innovative capabilities, MUSE will have a major impact on a broad swathe of astrophysical problems, ranging from studies of the most distant Universe to observations within the Solar System. The full science case can be found here. MUSE is uniquely well suited to the study of faint galaxies in the early Universe, and will be able to detect the small progenitors of the Milky Way galaxy at high redshift, thus providing a map of the mass assembly of galaxies at early epochs. It will also give new insights into the physical processes operating within young galaxies, and into the feedback mechanisms that control their development. Closer to home, MUSE will enable unprecedentedly detailed studies of the complex environments within galaxies, including those in star-forming regions and around the central black holes, sharpening our observational picture of the co-evolution of stars and black holes. Within our own Galaxy, MUSE will produce new understanding of proto-stellar objects and star-formation. Finally, MUSE will allow synoptic monitoring of solar system bodies at high resolution over extended periods of time.