Physics Topic 8 - Space

Question 1

Which galaxy is our solar system part of?

Answer 1

The Milky Way

Question 2

How many planets make up our solar system?

Answer 2

8

Question 3

What do the planets in our solar system orbit around and what kind of body is this?

Answer 3

-orbit around the sun
-sun is a star

Question 4

What type of force pulled together the cloud of dust and gas to form the sun?

Answer 4

Gravitational force of attraction

Question 5

What word is used to describe a cloud of dust and gas?

Answer 5

A nebula

Question 6

What type of reactions take place at the start of a star’s life cycle as dust and gas is drawn together?

Answer 6

Fusion reactions

Question 7

What factor determines the type of lifestyle a star undergoes?

Answer 7

The size of the star

Question 8

Which two phases do all stars of the same or greater size than the sun undergo?

Answer 8

1-protostar phase
2-main sequence phase

Question 9

What do stars of a similar magnitude to the sun become at the end of their life-cycle?

Answer 9

A black dwarf

Question 10

What two things can stars much bigger than the sun become at the end of their lifecycle?

Answer 10

1-neutron star
2-black hole

Question 11

What two phases do stars of similar size to the sun go through between a main sequence star and a black dwarf?

Answer 11

1-red giant
2-white dwarf

Question 12

What two phases do stars of greater size than the sun go through between being a main sequence star and a neutron star/black hole?

Answer 12

1-red super giant
2-supernova

Question 13

What are produced during the fusion processes in a star?

Answer 13

All of the naturally occurring elements

Question 14

What condition is required for fusion reactions to occur in a star?

Answer 14

Very high temperatures

Question 15

How are elements heavier than iron produced?

Answer 15

In a supernova

Question 16

What type of nuclei fuse together to form heavier elements in a star?

Answer 16

Hydrogen nuclei fuse to form heavier elements

Question 17

How are elements distributed throughout the universe?

Answer 17

Through the explosion of a massive star (supernova)

Question 18

What allows planets and satellites to maintain circular orbits?

Answer 18

-gravity provides the gravitational force that acts as the object’s centripetal force
-the presence of a centripetal force allows for the object to maintain its circular orbit

Question 19

What type of satellite can a planet’s moon be described as?

Answer 19

A natural satellite

Question 20

Explain why for a stable orbit, the radius of orbit must change if the speed changes

Answer 20

-at higher speeds, the object requires a grater centripetal force
-for a greater centripetal force, the gravitational force must increase
-this is achieved by the radius of the orbit being reduced

Question 21

what is red-shift?

Answer 21

An observed increase in the wavelength of light from distant galaxies

Question 22

What two things can be said about the motion and wavelength of emitted light from a galaxy, the further away it is?

Answer 22

-the further away a galaxy, the faster it is moving
-the further away a galaxy is, the greater the observed increase in wavelength

Question 23

What does red-shift provide evidence for?

Answer 23

-provides evidence that the universe is expanding
-supports the Big Bang theory

Question 24

What does the Big Bang theory suggest?

Answer 24

The entire universe started form a very small, hot and dense region in space

Question 25

What did scientists observe to provide evidence that the universe is expanding at an ever faster rate?

Answer 25

They observed supernovae, which suggested that galaxies are moving away at an ever faster rate than

Question 26

What two ideas could explain the universe’s ever increasing rate of expansion?

Answer 26

-the existence of energy and mass that we can’t detect, known as dark matter and dark energy
-these ideas are still being developed by scientists and are not yet fully understood