Saturn will appear as the third vertex of this planetary triangle, just 2 - 3° from Mercury (roughly the width of two fingers ...

Catch two transits of Io, spot sparkling star clusters, and view Mars at aphelion while the April Full Moon lights the sky this week.

The swirling, paint-like clouds in the darkness of space in this stunning image seem surreal, like a portal to another world ...

In a star’s core, fusion takes terrific temperature and pressure that is provided by the crushing gravity of the star’s overlying mass. For a star to be relatively stable, the outward force of the ...