On July 16, 1969, Armstrong, Edwin E.
(Buzz) Aldrin, Jr., and Michael Collins
left for the Moon in the Apollo 11
spacecraft. Four days later, Aldrin and
Armstrong landed on the Moon in the
Eagle, a landing vehicle that separated
from the Apollo spacecraft. Armstrong
was the first to step out onto the Moons
surface. For more than two hours he and
Aldrin collected samples of Moon soil,
made measurements, and took photographs
before they began their return
trip to Earth.
Armstrong retired from NASA in 1971.
He continued to teach and to work on
committees about the space program.
#More to explore
Moon Space Exploration
Army
An army is a large, organized group of
soldiers trained to fight other armies or
groups. An armys main job is usually to
defend its country in times of war. An
army protects the country against
attacks or invasion by enemies. It may
also fight in other parts of the world.
An army is usually one of several major
branches of a countrys armed forces. In
the United States the other major
branches are the Air Force and the Navy
(which includes the Marine Corps).
Armies Today
Modern armies have ranks, or levels of
power. The soldiers who command soldiers
in lower ranks are called officers.
The officers in the highest ranks are the
generals. The generals are in charge of
the army as a whole. Beneath the generals
are the commissioned officers. They
are graduates of special military training
schools. Beneath them are the noncommissioned
officers. These are men and
women who started out as ordinary soldiers
and moved up through the ranks.
The ordinary soldiers, or privates, make
up the lowest ranks of an army.
Neil Armstrong
Soldiers stand in formation at a U.S. Army
post in Hawaii.
BRITANNICA STUDENT ENCYCLOPEDIA Army 189
Sometimes people are drafted, or
ordered by their government to join the
army. Drafts are common in times of
war when too few people volunteer. For
example, the United States, Canada, and
the United Kingdom had drafts during
WorldWar II. Today, however, volunteers
make up these countries armies.
Some countries, such as China and
Israel, still require most of their citizens
to serve time in the army.
History
The first army was probably organized
in Sumer, a civilization that began more
than 6,000 years ago in the Middle East.
The earliest soldiers fought with swords,
shields, and bows and arrows. They protected
themselves with armor.
Over the centuries, new developments
in warfare changed the way armies
fought. Arabs and Europeans invented
weapons that used gunpowder in the
1300s. Armies began using machine
guns in the 1800s and bombs in the
1900s. Armies continue to develop new
weapons. New technology also has
helped improve communications and
protect soldiers on the battlefield.
#More to explore
Air Force Armor Bomb Marines
Navy War
Artemis
In ancient Greek mythology Artemis
was the goddess of wild animals and
hunting. She was one of the 12 main
gods believed to live on Mount Olympus.
Artemis was associated with the
Roman goddess Diana because they
shared many of the same characteristics.
The cypress tree and wild animals were
sacred to Artemis.
Artemis was the daughter of Zeus, the
chief Greek god, and Leto. Leto was a
China has the
worlds largest
army.
190 Artemis BRITANNICA STUDENT ENCYCLOPEDIA
Titan, or one of the giants who once
ruled the world. Artemis was the twin
sister of Apollo, the god of music and
light. Apollo was associated with the
sun, while Artemis was associated with
the moon. Some people believed that
Artemis helped women during childbirth.
Artemis was a protector of animals,
but she also hunted them. Artists
showed Artemis with a deer or with her
hunting dog and silver bow, a weapon
used to shoot arrows.
According to one story, Artemis loved
the giant huntsman Orion and lived
with him in the forest. Eventually, Artemis
became jealous. She thought that
Orion loved another woman. In
revenge, Artemis shot Orion with an
arrow. Orion was placed in the sky after
his death. There he became a constellation
(a group of stars).
#More to explore
Apollo Greece, Ancient Mythology
Zeus
Arthritis
Arthritis is a common medical problem
for older people. Sufferers of arthritis
experience swelling, pain, and redness in
the jointsthe places where the bones
meet. Arthritis commonly affects the
spine, hips, knees, and hands. It may
also attack many other parts of the body.
In severe cases, people may find it difficult
or even impossible to move the
joints at all.
Arthritis seems to run in families. People
whose parents or grandparents had
arthritis often get it themselves. Infections
and injuries can cause rarer types
of arthritis.
In most cases, arthritis is a lifelong condition
without a cure. However, aspirin,
ibuprofen, or other drugs may help to
relieve the pain and swelling. Exercise
may help to increase movement. In
some cases doctors may perform surgery.
They can remove unhealthy tissue or
replace severely damaged joints with
ones made of plastic or metal.
#More to explore
Bone Medicine
Arthur, Chester
When President James A. Garfield was
assassinated in 1881, Chester A. Arthur,
the vice president, rose to the highest
office of the United States. Because
many people did not believe that Arthur
would make a good president, he
worked hard to gain the publics respect.
Arthritis can bend fingers out of shape.
BRITANNICA STUDENT ENCYCLOPEDIA Arthur, Chester 191
Early Life and Career
Chester Alan Arthur was born on October
5, 1829, in the village of Fairfield,
Vermont. He was the son ofWilliam
Arthur, a Baptist minister, and Malvina
Stone. Chester entered Union College in
Schenectady, New York, when he was
only 15. After graduating at age 18, he
studied law while teaching. In 1859
Arthur married Ellen Lewis Herndon.
The couple had three children.
Beginning in 1854, Arthur worked as a
lawyer in New York City. He became
known for his antislavery principles.
Arthur won the case of slaves who
demanded their freedom after coming to
the free state of New York. Arthur also
represented an African American woman
who had been forced off a streetcar
reserved for whites. His success led to a
New York law against discrimination in
public transportation.
Political Career
In the 1850s Arthur helped to organize
the new Republican Party in New York
State. In 1868 he worked on Ulysses S.
Grants successful presidential campaign.
In 1871 President Grant appointed
Arthur customs collector for the port of
New York City. In 1880 the Republicans
nominated Garfield for president and
Arthur for vice president. The Republi-
October 5, November 18,
1829 1854 1880 1881 1883 1885 1886
Arthur is born
in Fairfield,
Vermont.
Arthur becomes
a lawyer. In his
law career he
defended the
rights of African
Americans.
Arthur is
elected vice
president under
President James
A. Garfield.
Arthur
becomes
president after