Ask Astro

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 are NGC objects, and where did this catalog come from?

Exoplanets

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

Science

How does spectroscopy work?

Observing, Observing Basics

Why aren’t the constellations always drawn the same way?

Science

What is a light echo?

Observing, Observing Basics

How do light pollution filters work?

Cosmology

Is there a hottest temperature possible in the universe?

Cosmology, Exotic Objects

Astronomers say they’ve spotted the oldest, most distant black hole. How do they know this?

Stars

How do Cepheid variables indicate distance?