What’s a black hole? What will a larger aperture telescope get you? This is the place to come for answers to almost every astronomy question you can think of — and many you haven’t.

Science-Based Q&A

Deepen your knowledge of astronomy as a science as you browse these Q&As and learn about the universe’s fascinating array of celestial bodies, from planets to stars to black holes. Discover the difference (and evidence for) dark energy and dark matter, and learn about worlds closer to home such as Venus and Saturn.

Solar System

Eight planets await



Comets, Asteroids & Meteors


Universe Timeline
A timeline of the universe from the present day (left) to the Big Bang (right).
NASA / ESA / B. Robertson / A. Feild


Milky Way

Milky Way globular clusters
Globular clusters around a computer-generated model of the Milky Way
ESA / Hubble, NASA / L. Calçada

Black Holes

Illustration of black hole merger
Two black holes prepare to merge in this artist's illustration.
LIGO / Caltech / MIT / Aurore Simonnet (Sonoma State)


Labeled Big Dipper
The Big Dipper
Akira Fujii

By Wavelength

Astronomy & Society

The Kavli Foundation Q&As

An artist’s impression of a supernova
NASA / ESA / G. Bacon (STScI)

Hobby-Based Q&A

Delve into the hobby of astronomy: learn about different types of equipment and what they can do, and discover the limits (read: challenges) of observing the night sky with instruments and the unaided eye. The Q&As presented here cover a wide range of readers' questions, and we’ve responded with detailed and well-researched answers. Search for a specific question or just browse through — our readers have come up with some interesting hypotheticals over the years!

If there’s a question that hasn’t been asked, ask it yourself by sending a note to [email protected].

General Observing

Observing the Sun

An abundance of spots
Bob King

Observing the Moon

Mahdi Naseri / Online Photo Gallery

Observing Satellites

Observing the Planets

Two at twilight
Mars and Venus were just ¾° apart the morning of October 4th, seen here reflected in Lake Superior in Duluth, Minn.
Bob King

Observing Comets, Asteroids & Meteors

Shakeel Anwar / Online Photo Gallery

Observing Stars


407 Perseid composite
Astrophotographer Petr Horálek created this mosaic of 407 Perseid meteors using photos taken over nine nights between August 6-14, 2018 at Kolonica Observatory in Slovakia. The composite required nearly 450 hours of post-processing. For the full image and the story of how it was made, go to Petr Horalék Photography.

Astronomy Equipment

reflecting telescopes can't see vampires
Randall Munroe, xkcd / CC BY-NC 2.5


Amateur Telescope-Making

Eyepieces / Optics



Questions on Sky & Telescope Articles

Sky Atlas Questions

Math Questions

Really, Really Miscellaneous Questions