Browse
World

World Overview
Atlas
Countries
Disasters
News
Flags of the World
Geography
International Relations
Religion
Statistics
Structures & Buildings
Travel
World Rulers

People

People Overview
Academia & Culture
Arts & Entertainment
Business
Government
Newsmakers
Science
Sports
U.S.

U.S. Overview
Cities
U.S. Documents
Gender Issues
Geography
Government
News
Military
Monuments & Landmarks
Postal Information
Race & Ethnicity
States
Statistics
Arts & Entertainment
Sports

History

History Overview
Timelines
World History
U.S. History
Black History Month
Hispanic Heritage Month
Women's History Month
Math & Science

Math & Science Overview
Aviation
Biology
Computers & Internet
Earth & Environment
Health
Inventions & Discoveries
Mathematics
Physics
Space
Weather
Weights & Measures

Calendar & Holidays

Calendar & Holidays Overview
Calendars
Holidays
Seasons, Months, Days
Perpetual Calendar
Business

Business Overview
Business
Consumer Resources
Currency
Economy
Employment & Labor
Personal Finance
Poverty & Income
Taxes

Primary Sources

Primary Sources Overview
Philosophy & Religion
Fables & Fairy Tales
Government
History & Biography
Poetry
Speeches & Essays
Books & Plays

Ask the Editors

View All Questions & Answers
Tools
Conversion Calculator
Latitude & Longitude
Perpetual Calendar
Dictionary
Thesaurus
Distance Calculator
Periodic Table
Videos
Spellcheck
Atlas

Atlas Tools Menu
Atlas »
Learn more about the world with our collection of regional and country maps.

Title

Maps of Europe

Brush up on your geography and finally learn what countries are in Eastern Europe with our maps.
Maps of Europe »

Title

Maps of the Middle East

Not sure about the geography of the middle east? We've got you covered with our map collection.
Maps of the Middle East »

Encyclopedia

Encyclopedia Tools Menu
Encyclopedia »
Need a reference? Check our encyclopedia for a gloss on thousands of topics from biographies to the table of elements.

Title

The Trojan War

Learn more about the mythic conflict between the Argives and the Trojans.
The Trojan War »

Title

Buddhism

Learn about one of the world's oldest and most popular religions.
Buddhism »
Tools
Conversion Calculator
Latitude & Longitude
Perpetual Calendar
Dictionary
Thesaurus
Periodic Table
Distance Calculator
Videos
Atlas
Encyclopedia
Quizzes
Top 10s
Day In History

Search

Breadcrumb

Home >
Math & Science >
Space >
Astronomical Measurement

Astronomical Measurement

How Bright Is Bright?

Astronomical Constants

A Star's Magnitude

Conversion of Universal Time (UT) to Civil Time

Earth's moon

The Solar System

The Solar System Space

Sources +

Our Common Sources

Encouraging curious minds for nearly a century.

Infoplease knows the value of having sources you can trust. Infoplease is a reference and learning site, combining the contents of an encyclopedia, a dictionary, an atlas and several almanacs loaded with facts. Our editors update and regularly refine this enormous body of information to bring you reliable information.

Footer

About Us
Editorial Policy

Advertise with Infoplease

Citing Infoplease

Do Not Sell My Info (for CA Residents)

Infoplease is part of the Sandbox Learning family of educational and reference sites for parents, teachers and students.

©2022 Sandbox Networks Inc. All rights reserved. Sandbox Learning is part of Sandbox & Co., a digital learning company.