Threats to Earth

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Slide 1

Threats to Earth

Slide 2

Objectives

In this lesson we should learn:

about the properties of asteroids

how asteroids have affected Earth in the past

Slide 3

Outcomes

Foundation Paper

You should now be able to

State that large asteroids have collided with the Earth in the past and describe some of the consequences and evidence of such collisions

State that asteroids are rocks and describe that asteroids are left over from the formation of the Solar System and where they can be found.

Higher paper

Explain why the asteroid belt is between Mars and Jupiter: the large gravity of Jupiter disrupts the formation of a planet

Slide 4

The asteroid Gaspra, found in the Asteroid Belt between Mars & Jupiter

Slide 5

Asteroid Ida with it’s moon Dactyl

Slide 6

Asteroids

Asteroids are large rocks left over from the formation of the Solar System

They are mostly between the orbits of Mars and Jupiter

Asteroids (large rocks) have collided with the Earth in the past causing:

- craters,

- ejection of hot rocks,

- widespread fires,

- sunlight blocked by dust,

- climate change,

- species extinction

Slide 7

Collisions?

The evidence for past collision on Earth includes:

- craters

- layers of unusual elements in rocks

- sudden changes of fossil numbers between adjacent layers of rock.

Slide 8

Slide 9

Outcomes

Foundation Paper

You should now be able to

qState that large asteroids have collided with the Earth in the past and describe some of the consequences and evidence of such collisions

qState that asteroids are rocks and describe that asteroids are left over from the formation of the Solar System and where they can be found.

Higher paper

qExplain why the asteroid belt is between Mars and Jupiter: the large gravity of Jupiter disrupts the formation of a planet

Slide 10

Objectives

In this lesson we should learn:

about the properties of comets

how astronomers are monitoring the danger from near-Earth asteroids and comets