Ask Astro

Observing, The Moon

How long would it take for an observer using binoculars to notice the Moon’s terminator moving?

Solar System

How big is Earth’s orbit around the Sun?

Cosmology

What is the universe expanding into?

Astrophotography

How are long-exposure astrophotos made? 

Deep-Sky Objects, Observing

Will my telescope show color when viewing deep-sky objects?

Solar System

How long will Saturn’s rings last before they disappear? 

Exotic Objects

Why weren’t astronomers sure that supermassive black holes could merge?

Science, The Moon

Why can we still see the Moon’s disk during a total lunar eclipse?

Exotic Objects

How can a black hole pull light into itself if a photon is massless?

Astronomy for beginners, Observing

What do NGC numbers mean?

Exoplanets

How is TESS able to spot more planets in the sky than Kepler could?

Science

How does spectroscopy work?