A Connecticut village in autumn is ablaze with the brilliant colors of turning leaves. Every year, many vacationers visit the state to enjoy its scenic countryside and to explore its many picturesque villages and historic sites.
Credit: © Corbis Bridge/Alamy Images

Fall means pumpkins, colorful leaves, and crisper weather. It also means the end of summer. What causes the seasons to change? The four seasons result from the tilt of Earth’s axis of rotation and the planet’s motion around the sun. The axis slants at an angle of 23 degrees 27 minutes in relation to the plane of Earth’s orbit. As a result, Earth’s Northern and Southern hemispheres tilt toward or away from the sun during different times of the year. Some people mistakenly believe that seasons result from Earth moving closer to or farther from the sun at different times of the year. But Earth orbits at nearly the same distance from the sun throughout the year. The small changes in distance that do occur have little effect on Earth’s weather.

Today, at 9:03 p.m. Eastern Time, the autumnal equinox marks the beginning of autumn in the Northern Hemisphere. In the Southern Hemisphere, where the seasons are reversed, the event is called the vernal equinox and marks the start of spring. The word vernal means of spring. An equinox is either of the two moments each year (the other is in March, again changing the seasons) when the sun is directly above Earth’s equator. On the days of the equinoxes, all places on Earth receive approximately 12 hours of sunlight. Today, the sun rose at 6:43 a.m. Eastern Time and will set at 6:53 p.m.—a total of 12 hours and 10 minutes of daylight. The term equinox comes from a Latin word meaning equal night. The equinoxes occur at different times of day each year on March 19, 20, or 21 and on September 22 or 23.

The time interval from the March equinox to the September equinox is longer than that between the September equinox and the next March equinox. This time difference results from the Earth’s elliptical (oval-shaped) orbit around the sun. Our planet moves faster in its orbit when it is closer to the sun. The distance between the Earth and the sun is shortest in January. Therefore, the Earth completes the semicircle from the September equinox to the March equinox faster than it does the opposite semicircle.

Astronomers also use the term equinox for either of two imaginary points where the sun’s apparent path among the stars crosses the celestial equator. The celestial equator is an imaginary line through the sky directly over the equator.

After the autumnal equinox, the weather cools and nights become longer than days, and days continue to shorten until the winter solstice. The weather then warms and daylight begins its recovery toward the summer solstice in June. The winter solstice is technically the shortest day of the year, and the day of the summer solstice enjoys the most sunlight.

E-books are available for purchase on the websites of publishers and online bookstores. Some libraries offer e-books over the Internet at no cost. In this picture, a librarian demonstrates how to download a library book onto an e-reader.
Credit: AP Photo

September is Library Card Sign-up Month. Libraries around the world are waiting for you to stop by and check out what they have to offer! While you may think libraries are just for checking out books, they have so much more in store. From E-books to workshops, librarians stay busy reaching out to community members like you. Libraries hold troves of information beyond the stacks of books – in their databases! Many libraries hold book clubs, workshops for various hobbies, career fairs, computer classes, and more!

A library is an organized collection of books and other materials. Such materials may include magazines, newspapers, maps, films, compact discs (CD’s), online databases, and other print, electronic, and multimedia resources. Libraries play a vital role in the world’s systems of communication and education. The numerous resources and services that libraries provide help people carry out their work, studies, and leisure-time activities. Libraries rank among society’s most important and useful cultural institutions.

The organization of materials is one of the central tasks of a librarian’s work. This library worker is shelving books according to call numbers, which reflect the subject matter of the books.
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Libraries provide access to knowledge and information that has been accumulated throughout history. People of all ages and all walks of life—including students, teachers, scientists, business executives, and government officials—use library resources for their work. In addition, large numbers of people turn to libraries to satisfy a desire for knowledge, to pursue a hobby, or to read in their free time. Many people also take part in special programs and events at libraries. Such events may include discussions, concerts, lectures, exhibitions, and story hours.

Libraries have graced the world since people began writing to record information about 5,500 years ago. Libraries back then were a pile of clay tablets, which makes libraries today seem like amusement parks! The most famous library of ancient times was the Alexandrian Library in Alexandria, Egypt. Alexander the Great founded Alexandria in the 330′s B.C. His successors as ruler of Egypt, Ptolemy I and Ptolemy II, developed the Alexandrian Library into the greatest collection of scrolls in the ancient world.

The Alexandrian Library in Alexandria, Egypt, was the most famous library of the ancient world. It had a copy of every existing scroll known to the library’s administrators.
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Today’s libraries differ greatly from libraries of the past—not only in the resources and services they offer, but also in physical layout and atmosphere. In turn, future libraries will differ from those of today. This is so because libraries constantly strive to expand and perfect the services they provide and the contributions they make to society.

The contents of libraries have changed so much through the years that the word library itself is, in a sense, inaccurate. The word comes from the Latin word liber, which means book. It is used because libraries traditionally were largely collections of books. Today’s libraries house many books, of course. However, they also have a wide variety of other resources that communicate, educate, and entertain.

Libraries provide access to information in a wide variety of formats. Library users can obtain information from books, magazines, manuscripts, newspapers, pamphlets, and online databases. Library users also have access to audio and visual materials such as CD’s, DVD’s, films, maps, paintings, and photographs.

In addition to regular books, a library may have large-type books, braille books, and recordings of books, called audiobooks. Librarians keep pace with the changing contents of libraries to serve as many people as possible. Their efforts have turned libraries into multimedia resource centers, which house educational and recreational materials in a variety of forms.

The expansion of library resources greatly increases the library’s ability to communicate and educate. For example, people interested in classical music can listen to CD’s and read books about famous composers. Individuals who enjoy art can use library computer terminals to search the Internet for informative writings, pictures, and video presentations. Students of agriculture can read magazines and watch films on farming methods.

Immigrants to the United States can find pamphlets on becoming a citizen and read books about the United States in their original language. In addition, many people use magazines, newspapers, and websites to find the most up-to-date information on current events.

School libraries also supply materials that students and teachers need for their work. The librarians teach students how to use a library and how to locate and evaluate information—skills that will benefit them throughout life. Head over to your local library to sign up today!

Sudoku puzzles contain numbers that are already filled in by the puzzle’s author, called clues, which allow the puzzle to be solved. The sudoku on the left is unsolved, and the numbers in black are the clues. The sudoku on the right has been solved, and the numbers in blue are the answers for the puzzle.
Credit: World Book illustration

Today, September 9th (or 9/9 depending on how you write the date), is International Sudoku Day. Sudoku is a logic puzzle. A standard Sudoku consists of a grid of 81 squares, made up of nine rows and nine columns. The grid is further divided into nine 3-by-3 boxes. Each puzzle comes with some numbers in place. A player solves the puzzle by filling the grid with numbers so that every row, column, and box contains the digits 1 through 9 without repeating a number. If the puzzle was properly made, it has only one solution. The amount of nines involved in the puzzle is why today was chosen to celebrate the beloved pastime!

There are some variations of standard Sudoku, with smaller or larger grids. Also, because no arithmetic is needed for Sudoku, letters or symbols can be used in place of numbers. Puzzles that use letters are sometimes called Wordoku.

The earliest examples of Sudoku were number logic puzzles called Number Place, first published in the United States in 1979. A Japanese company called Nikoli began publishing the puzzles in 1984. The puzzles became popular in Japan, where they were called Su Doku—a shortened form of a Japanese phrase meaning, roughly, “the numbers can only be used once.”

The Times of London published its first Sudoku in November 2004. Soon, rival London newspapers followed The Times, each attempting to outdo the others by supplying more Sudoku, or by claiming to offer better Sudoku. Magazines of the puzzles first appeared in the United Kingdom early in 2005. Within months, Sudoku had gained widespread popularity. To give Sudoku a try, grab your local newspaper to find the daily Sudoku puzzle next to the crossword or download an application to play it on a phone or computer. If you are working on paper, it is best to start learning by using a pencil instead of a pen!

September 11, 2019

If your birthday is in September, your birthstone—the gem associated with the month of your birth—is the sapphire. The sapphire, a variety of the mineral corundum, is a hard and clear gem. The best known sapphires are blue. Their color results from small amounts of iron and titanium in the stone. Sapphires are also found in many other colors, including yellow, green, white, black, violet, and orange. The red variety of corundum is known as a ruby, the birthstone of July. Sapphires have long been used in jewelry and decorative objects.

Sapphires are shown cut and polished, left, and uncut, right. The sapphire is the birthstone of the month of September. Credit: © Biophoto Associates/Photo Researchers

Traditionally, sapphires symbolize faithfulness, nobility, purity, and sincerity. Sapphires were once thought to allow clarity of mind and to ward off evil spirits. As the stone of the planet Saturn, sapphires offered a magical portal to heavenly realms. In ancient Greece and Rome, sapphires protected people from envy and harm. The gems have long been popular with royalty, and Roman Catholic bishops and other clergy have worn sapphire rings for centuries. The sapphire’s rich blue color is used to describe blue objects of particular beauty, such as Sapphire Lake in northern California. The sapphire is the traditional gem gift for a 45th wedding anniversary. In 2017, Queen Elizabeth II became the first British monarch to mark a 65th year on the throne with a sapphire jubilee.

The most valuable sapphires once came from Indian Kashmir. They are a magnificent cornflower blue, the color to which all sapphires are compared. Today, Thailand is the most important source of blue sapphires. Blue and fancy sapphires are also found in the Sapphire Mountains (naturally) of Montana and in Australia, Myanmar, and Sri Lanka.

Lovely star sapphires contain needles of the mineral rutile that reflect light in six starlike rays. The most highly prized star sapphires are blue. Black or white star sapphires are less valuable. One of the largest blue star sapphires, the Star of India, weighs 563 carats, or about 4 ounces (110 grams). It is on exhibit in the American Museum of Natural History in New York City.

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Birthstones, according to tradition, bring good luck when worn by a person born in the associated month. Credit: WORLD BOOK illustrations by Paul D. Turnbaugh

According to tradition, a birthstone brings good luck to a person born in its month. Each birthstone also corresponds to a sign of the zodiac. The belief in birthstones may have come from a Bible story about Aaron, the first high priest of the Israelites. The story describes Aaron’s breastplate, which was decorated with 12 precious stones. Early writers linked these stones with the 12 months of the year and the 12 signs of the zodiac. The custom of wearing a stone that represented a person’s zodiac sign probably originated in Germany or Poland in the 1700′s.