P2 - Threats to Earth. The Big Bang

Question 1

What are asteroids?

Answer 1

Rocks that are left over from the formation of the solar system

Question 2

What can the consequences be when an asteroid collides with Earth? Give three!

Answer 2

The impact crater could trigger the ejection of hot rocks, the heat may cause widespread fires, sunlight could be blocked out by the dust from an explosion,

Question 3

When an asteroid collides with Earth, why is it bad that sunlight could be blocked out by the dust from an explosion?

Answer 3

It would prevent plants from photosynthesising.

Question 4

What is a comet?

Answer 4

A small body with a core of frozen gas and dust

Question 5

Why can’t asteroids in the belt between Mars and Jupiter combine to form a new planet?

Answer 5

because the larger mass formed feels a greater pull from Jupiter’s strong gravitational pull and is attracted to Jupiter, which breaks it up.

Question 6

What is a Near Earth Object (NEO)?

Answer 6

An asteroid or comet that is on a possible collision course with Earth.

Question 7

What is used to determine the trajectories (probable paths) of NEOs?

Answer 7

Telescopes

Question 8

What steps can we take to reduce the threat that large NEOs pose to the human race?

Answer 8

Survey the skies with telescopes, monitor the NEO’s progress with satellites, and deflect the NEO with an explosion if a collision is likely

Question 9

If the moon was formed by a great impact, how would this happen?

Answer 9

The planets collide, the iron cores of each planet merge to form the core of the Earth, an less dense material becomes the moon and begins to orbit the Earth

Question 10

What does the Big Bang theory state?

Answer 10

That the universe started billions of years ago in one place with a huge explosion, and the universe is expanding

Question 11

When we look at the stars, what can we observe as evidence for the Big Bang theory?

Answer 11

Nearly all the galaxies are moving away from us, distant galaxies are moving away more quickly, and microwave radiation is received from all parts of the universe

Question 12

What is red shift?

Answer 12

The shifting of wavelengths of light towards the red end of the spectrum

Question 13

How can red shift be observed?

Answer 13

In the light we receive from galaxies

Question 14

What is the relationship between the distance of a galaxy and the magnitude of the red shift and what does this mean?

Answer 14

The further away the galaxy, the greater the red shift. This means that galaxies further away from us are travelling faster than those closer to us

Question 15

Why does measuring red shift provide evidence for the expansion of the universe?

Answer 15

Because by tracking the movement of the galaxies, we can estimate the age and starting point of the universe

Question 16

How is a proto-star formed?

Answer 16

When interstellar gas clouds collapse under gravitational attraction. Then thermonuclear fusion reactions take place, releasing massive amounts of energy and increasing the star’s temperature. During this time, the star experiences a long period of normal life. But eventually the supply of hydrogen runs out, causing the end of the star

Question 17

What is a main sequence for a star?

Answer 17

During thermonuclear fusion reactions, the star experiences a long period of normal life

Question 18

What does the type of end depend on for a star?

Answer 18

Largely on the mass of the star

Question 19

What do stars start as?

Answer 19

Huge clouds of gas

Question 20

What are the end stages of a heavyweight star?

Answer 20

The stars swells up to form a red supergiant, the red supergiant rapidly shrinks and explodes, releasing massive amounts of energy, gas and dust into space. This is a supernova. Stars up to ten times the mass of our Sun form neutron stars. Stars greater than ten times the mass of our Sun leave behind black holes

Question 21

What are neutron stars made of?

Answer 21

Very dense matter

Question 22

Why can black holes be observed only indirectly through their effects on their surrounds?

Answer 22

Because light cannot escape from a black hole because its gravitational pull is too big.

Question 23

What are the end stages of a medium weight star like our sun?

Answer 23

The star swells up to become a red giant, and the core of the red giant contracts to be surrounded by outer shells of gas (planetary nebula), then the core cools and contracts to become a white dwarf

Question 24

What did the Ptolemaic model of the universe state?

Answer 24

That the Earth was the centre of the universe (The geocentric model), and that the Earth was surrounded by crystal spheres which held the other planets and the stars

Question 25

What did the Copernican model of the universe state?

Answer 25

That the planets sat on spheres, a fixed distance from the sun, the stars were fixed of the outermost sphere and didn’t move, but differs from the Ptolemaic model in that it stated that the Sun is the centre of the universe, the Earth is rotated every 24 hours, and the Earth takes one year to revolve around the sun.

Question 26

What did Galileo discover?

Answer 26

That the moon isn’t a perfect sphere, four moons orbiting Jupiter, that venus has phases like the moon, meaning that it couldn’t be attached to a crystal sphere, and that it orbits the Sun like the Earth.

Question 27

Why were the theories of Galileo and Copernicus not widely accepted?

Answer 27

Because their ideas were in direct opposition to the Catholic church’s belief that the Earth was the centre of the universe

Question 28

What is the heliocentric theory?

Answer 28

That the Sun is the centre of the solar system

Question 29

What led to the acceptance of the heliocentric theory?

Answer 29

Advances in technology and the ability to build more powerful telescopes