This puzzle is known as the problem of time, and it remains one of the most persistent obstacles to a unified theory of ...

Oftentimes, we think of space as an endless, mostly empty vacuum, a silent backdrop where planets, stars, and galaxies play out their dance. We also think of time as something separate, a steady ...

The Committee on Solar and Space Physics (CSSP) provides an independent, authoritative forum for identifying and discussing issues in solar and space physics with the research community, the federal ...