Britannica Student Encyclopedia - 2010

from the city sell their famous glass and

lace products to tourists. Trade, shipbuilding,

fishing, and manufacturing

also bring money to Venice.

History

People settled the islands of Venice in

the 500s. They moved there to escape

invaders on the Italian mainland.

A series of dukes, called doges, ruled

Venice from the 700s until 1797. It

developed into an independent power

called a city-state. Venice controlled

important trade routes and grew wealthy

from sea trade. In the 1200s it began

taking over other territories in the

region. Venice achieved its greatest

power and wealth in the 1400s.

Venice began to decline in the 1500s. It

gradually lost the lands of its empire in

wars with other powers. Austria took

control of Venice in 1797. The city has

been part of Italy since 1866.

In modern times air pollution and

regular flooding have damaged Venice’s

great buildings. Also, the islands have

Boats called gondolas gather for a special

event on the Grand Canal of Venice, Italy.

BRITANNICA STUDENT ENCYCLOPEDIA Venice 65

 

been sinking into the lagoon at an

alarming rate. In the 20th century the

city began projects to try to control

these problems.

#More to explore

Canal • Italy

Venus

Venus is one of the planets that orbit,

or travel around, the sun in the solar

system. Venus is the brightest planet in

the sky when viewed from Earth. It is

Earth’s nearest neighbor, coming closer

to Earth than any other planet. Venus is

the second planet from the sun. Its

distance from the sun averages about 67

million miles (108 million kilometers).

It is the hottest planet in the solar

system.

Physical Features

Venus is about the same size and weight

as Earth. Its diameter, or distance

through its center, is about 7,500 miles

(12,100 kilometers). It is solid and

rocky. Scientists believe that Venus also

has layers like Earth’s. These layers consist

of a metal core, a thick rocky

middle, and a crust.

In the past lava from erupting volcanoes

shaped the surface of Venus. Most of the

landscape is gently rolling plains. Venus

also has tall mountains.

The atmosphere, or layer of gases, surrounding

Venus is thick and heavy. Also,

thick clouds always cover the planet.

The gases and clouds trap heat. The

temperature near Venus’ surface is about

867° F (464° C). Its surface is hot

enough to melt lead.

Orbit and Spin

Like all planets, Venus has two types of

motion: orbit and spin. The orbit is the

path it takes as it travels around the sun.

Venus orbits the sun in a nearly perfect

circle. Venus takes 225 Earth days to

complete one orbit. In other words, one

year on Venus lasts 225 Earth days.

Venus also spins, or rotates about its

center. A planet’s orbit and spin combine

in a complex way to determine the

length of a day on that planet. For most

planets a day is almost equal to the time

it takes to complete one rotation. Venus

is unusual in that the length of its day is

very different than the time it takes to

complete one rotation. The planet takes

243 Earth days to complete one rota-

A view of Venus taken by the Magellan

spacecraft shows the planet’s highest mountain

range. It appears as a bright spot near

the center of the photograph.

66 Venus BRITANNICA STUDENT ENCYCLOPEDIA

 

tion, but a day on Venus lasts only about

117 Earth days. A day on a planet is the

time it takes for the sun to appear

straight overhead, to set, and then to rise

straight overhead again.

Observation and Exploration

People have observed Venus from Earth

since ancient times. In addition, more

than 20 unmanned spacecraft have visited

the planet. The U.S. Mariner 2

spacecraft passed by Venus in 1962. It

was the first spacecraft to fly near

another planet. In 1970 the Soviet

Union’s Venera 7 landed on Venus. It

was the first spacecraft to successfully

land on another planet. In the 1990s the

U.S. Magellan spacecraft mapped Venus’

surface in great detail. The European

Space Agency sent a craft to study

Venus’ atmosphere in 2005.

#More to explore

Earth • Planets • Solar System • Space

Exploration

Venus, goddess

#see Aphrodite.

Venus’s-flytrap

The Venus’s-flytrap is a plant that traps

and eats insects. It belongs to a group of

carnivorous, or meat-eating, plants. This

group also includes sundews and pitcher

plants. The scientific name of the

Venus’s-flytrap is Dionaea muscipula.

In the wild the Venus’s-flytrap grows

only in parts of North and South Carolina,

in the United States. It grows best

in soil that is damp.

The Venus’s-flytrap grows from a bulblike

root. It reaches heights of between 8

and 12 inches (20 to 30 centimeters)

and produces small, white flowers. The

leaves of the plant grow in rounded

halves. The halves are hinged together

on one side like jaws. Each half has long

spikes along its edge and three hairs on

top that are sensitive to touch. The leaf

oozes a sticky substance that attracts flies

and other insects.

When an insect crawls between the two

halves of a leaf, the hairs detect its presence.

In less than a second, the leaf

snaps shut and the long spikes lock

together. The leaf then releases digestive

juices that break down the insect into

nutrients. The leaf absorbs the nutrients