BISL 04-Weather and Climate

16 CLIMATOLOGY WEATHER AND CLIMATE 17

Colors in the Sky

A

natural spectacle of incomparable beauty, the auroras are

produced around the magnetic poles of the Earth by the activity

of the Sun. Solar wind acts on the magnetosphere, which is a

part of the exosphere. In general, the greater the solar wind, the more

prominent the aurora. Auroras consist of luminous patches and columns

of various colors. Depending on whether they appear in the north or

south, they are called aurora borealis or aurora australis. The aurora

borealis can be seen in Alaska, Canada, and the Scandinavian countries.

BOW SHOCK WAVE

MAGNETOTAIL OVAL AURORA

THE SUN

emits solar

winds, which

cause serious

damage and an

increase in

temperature.

SOLAR WIND

THE POLES

The auroras are more

noticeable near the poles;

they are called aurora

borealis in the Northern

Hemisphere and aurora

australis in the Southern

Hemisphere.

THE EARTH

The Earth's

magnetosphere is

responsible for

protecting the

planet from the

deadly and harmful

solar winds.

10-

minutes

duration of the

phenomenon

The amount of light emitted

oscillates between 1 and 10 million

megawatts, equivalent to the

energy produced by 1,000 to

10,000 large electric power plants.

620 miles

(1,000 km)

is how long an aurora can be.

From space it will look like a

circle around one of the

magnetic poles of the Earth.

THEY BECOME

EXCITED

After the shock, the atoms

receive a significant

additional energetic charge

that will be released in the

form of photons (light).

2

THEY GENERATE LIGHT

Depending on the altitude and the

velocity where the shock is produced,

the aurora displays different colors.

Among the possibilities are violet,

green, orange, and yellow.

3

ELECTRONS COLLIDE WITH

MOLECULES

The oxygen and nitrogen molecules

receive the impact of the particles

from the Sun. This occurs in the

magnetosphere (exosphere).

1

310-370 MILES

(500-600 KM)

55-300 MILES

(90-500 KM)

0-6 MILES

(0-10 KM)

Nitrogen atoms

and molecules

emit violet light.

Sodium atoms

and molecules

emit a yellowish

orange light.

MAGNETOSPHERE

(EXOSPHERE)

MESOSPHERE

TROPOSPHERE

Oxygen atoms

and molecules

emit green light.

The auroras are the result of

the shock produced as ions

coming from the Sun make contact

with the magnetic field of the Earth.

They appear in different colors

depending on the altitude at which

they are produced. Moreover, they

demonstrate the function of the

magnetosphere, which protects the

planet against solar winds.

How They Are Produced

Solar Winds

The Sun emits radiation, continuously and

in all directions. This radiation occurs as a

flow of charged particles or plasma, which

consists mainly of electrons and protons. The

plasma particles are guided by the magnetic

field of the Sun and form the solar wind, which

travels through space at some 275 miles per

second (450 km/s). Particles from the solar

wind arrive at the Earth within four or five days.

A satellite image of

the aurora borealis

NORTH POLE