Science Objectives

1. High-resolution spectroscopy of low energy x-rays from diffuse hot plasmas in the intergalactic medium (IGM), interstellar medium (ISM), and heliosphere

• To find the current locations and properties of the baryons (normal matter) that were created in the early universe
• To understand the role of hot material in the life cycles of galaxies and stars

2. Support of NASA Themes

• Structure and Evolution of the Universe
  How did structure in the Universe form?
  What are the cycles of matter and energy in the evolving Universe?
• Astronomical Search for Origins
  How does the chemical enrichment of the IGM & galaxies take place?
  What is the role of the hot ISM in the life cycle of stars?
• Sun-Earth Connection
  Exploration of the heliosphere - how do the Sun and the Galaxy interact?

3. Science Questions to Answer - Filling in the Knowledge Gaps

• Is our understanding of structure formation in the universe correct?
• Are the missing baryons in the warm/hot intergalactic medium?
• What is the nature of the galactic winds that enrich the intergalactic medium with heavy elements?
• Does the bulge of our galaxy supply the energy to our galactic halo; does it drive a galactic fountain or wind?
• What are the temperatures, densities, and elemental abundances of the hot ISM and other remnants of
  energetic galactic events?
• Does the heliosphere glow in x-rays from the solar wind interacting with the incoming local ISM material?