Rogier A. Windhorst, Arizona State University
James Webb Space Telescope (JWST) Interdisciplinary Scientist

In the last 20 years, the Hubble Space Telescope has revolutionized our
knowledge of the Universe, providing us with an unprecedented view of
all classes of objects in the sky, from local stars to the most distant
galaxies. Despite this, many fundamental questions remain un-addressed:
How and when were the first stars made? What are the sources that
re-ionized the Universe? What is the interplay between massive Black
Holes and stellar populations, and how did Black Holes affect the
formation of massive galaxies? How are stars formed in the local
Universe? Can we detect and characterize planets around stars nearby
our Sun?

These and other fundamental question cannot be addressed by Hubble,
whose instruments are aging, and cannot be refurbished after the end of
the Shuttle program. The time is ripe for its successor: the James Webb
Space Telescope (JWST). With its mirror of 6.5m in diameter -- nearly 3
times the Hubble -- and its unique instrumentation, Webb is the most
ambitious and complex telescope ever designed and built. It is
scheduled for launch in 2018 and will operate from an ``L2 orbit'' 1
million miles from Earth, beyond possible repair by human crews. As of
summer 2014, significant progress has been made on the design and
fabrication of Webb: more than 97% of its launch mass has been built,
passed final design, or is being built.

I will focus on the major scientific discoveries expected from
Webb. They range from the discovery and characterization of Earth-like
exoplanets around stars in our Galaxy to finding the first stars and
galaxies in the very early Universe. I will show how Webb can measure
star-formation, including new young solar systems, and how it may find
water and carbon-dioxide in the atmospheres of Earth-like exoplanets
transiting around nearby stars.