Astronomy Questions & Answers

What’s a black hole? What’s inside a black hole? What’s the difference between a reflecting and refracting telescope? This is the place to come for answers to almost all the astronomy questions you can think of — and many you haven’t. Find answers to your equipment and hobby questions, as well as astronomy facts about the other planets in the solar system, stars, and galaxies.

Is Andromeda Galaxy headed for a clash with the Milky Way? What’s the faintest thing you can see with a ground-based telescope? From stargazing advice to stellar science, browse this Astronomy Q&A category, browse astronomy questions by topic, or email us with your own question at to deepen your knowledge of astronomy as a hobby and a science.

Low Sun, Long Shadows and Icy Atmospherics

What is the Winter Solstice?

The moment the Sun reaches its southernmost point in the sky marks the December solstice, the official beginning of winter in the Northern Hemisphere (where it is called the winter solstice) and a time of great celebration in many northern cultures.

High-Definition Space Telescope (HDST)

Kavli Foundation Q&A: Searching for Alien Life with a “Super-Hubble” Space Telescope

Watch a Q&A with two astronomers on the promise of Hubble's successor telescope, courtesy of The Kavli Foundation. Scientists have unveiled a bold proposal for a giant new space-based telescope that would be far more powerful than today's observatories. Called the High Definition Space Telescope (HDST), the instrument is essentially a supersized Hubble Space Telescope,…