Astronomy Colloquium

I will describe the current plans for a Next Generation Sky Survey that will begin After SDSS-IV --- AS4.  AS4 will be an unprecedented all-sky spectroscopic survey of over six million objects. It is designed to decode the history of the Milky Way galaxy, trace the emergence of the chemical elements, reveal the inner workings of stars, and investigate the origin of planets. It will also create a contiguous spectroscopic map of the interstellar gas in the Milky Way and nearby galaxies that is 1,000 times larger than the state of the art, uncovering the self-regulation mechanisms of our Galactic ecosystem. It will pioneer systematic, spectroscopic monitoring across the whole sky, revealing changes on timescales from 20 minutes to 20 years.   The project is now developing new hardware to build on the SDSS-IV infrastructure, designing the detailed survey strategy, and is actively seeking to complete its consortium of institutional and individual members.