Magazine

Deep-Sky Objects

Since the discovery of the “Pillars of Creation,” what changes have occurred within them and the surrounding area?

Exoplanets, Planets, Solar System

Can you explain Mercury’s retrograde motion? Do other planets appear to do this also?

Exoplanets, Observing, Planets, Solar System, The Moon

A gemlike shower

Cosmology

Does dark matter collect into dense concentrations like stars? And, if not, why?

Exoplanets, Exotic Objects, Planets

Weird Object: Pulsar Planets

Robotic Spaceflight, The Sun

Weird Object: The IBEX Ribbon

Exoplanets, Planets, Robotic Spaceflight, Solar System

Weird Object: Iapetus

Exoplanets, Planets, Robotic Spaceflight, Solar System

Weird Object: Uranus’ Moon Miranda

Observing

Just a coincidence

The Moon

Why does the daily moonrise time vary by as much as 60 minutes, and as little as 30 minutes during the same month?

Exoplanets, Observing, Planets, Solar System, The Moon

Predawn planet parade

Solar System

As Earth was molten early during its formation, dense metals should have sunk toward the core, yet iron is found closer to the surface. Did asteroids and comets deliver some of these materials?