30 CHAPTER 2

Asteroid Hit!For years, scientists speculated that the extinction ofdinosaurs was due to one very large “environmentalevent.” Today we know that event was most likely theimpact of an asteroid about six miles wide. Sixty-fivemillion years ago it slammed into the earth traveling athousand times faster than a rifle bullet. Fallout from theasteriod impact changed the environment so drasticallythat 50 to 70 percent of all living species on earth werewiped out.

The asteroid hit nearChicxulub (CHEEK•shoo•loob) on the YucatánPeninsula of Mexico. Itdug a crater about 62miles (100km) across.

100km crater diameter

Direction of asteroid

Yu

ca

t án

Pe

ni n

s ul a

Labná

Dzibilchaltún

MéridaIzamalAcancéh

Mayapán

Chicxulub

Uxmal

Chichén Itzá

20°N

88°W90°W

G u l f o fM e x i c o

0

0 50 100 kilometers

50 100 miles

Azimuthal Equidistant Projection

N

S

EW

Chicxulub

YucatánPeninsula

Caribbean Sea

Gulf ofMexicoM

E

XI C O

U N I T E D S T A T E S

Disasters! 31

ASTEROIDS• Asteroids are small planetary

bodies that orbit the sun.

• There are an estimated 50,000asteroids in our solar system.

• Asteroids range in size from 20 feetto 580 miles in diameter.

• Fragments of asteroids that reachthe earth are called meteorites.

TUNGUSKA EVENTOn June 30, 1908, at about 7:30 A.M.,an explosion occurred over theTunguska region of Siberia. This eventmight have been an asteroid hit.

• The force of the explosion wasestimated at between 10 and 20megatons of TNT.

• The fireball and explosion wereseen and felt 500 miles away.

• Five hundred thousand acres offorest were flattened and burned.

• More than 600 grazing reindeerwere roasted instantly.

• No crater could be found.

CREATING A FRONT PAGEWith a small group, use the Internetto research the Chicxulub event.Then create the front page of anewspaper describing the event.

• Create a map showing theimpact area.

• Add an article describing thedestruction caused by the asteroid.

• Write an interview with a scientistwho predicts event results.

The asteroid plows intothe earth at 150,000 mph,vaporizing limestone andseawater. It creates animmense fireball thatcauses fires thousandsof miles away.

The Earth’s skies are darkened forseveral months by 25 trillion tons ofrock, dust, and smoke from the impact.Acid rain created by vaporized mineralspoisons lakes and rivers. Food chainscollapse, and plants and animals die.

A thick layer of carbon dioxideis trapped in the atmosphere,creating a “greenhouse effect”for perhaps a thousand years or more. Ferns, burrowingmammals, and some freshwateranimals survive. Some eventhrive in the new climate.

RESEARCH LINKSCLASSZONE .COM

http://www.classzone.com/books/world_geography05/index.cfm

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