space

Question 1

how long ago was the universe created?

Answer 1

the universe was created 13.7 billion years ago

Question 2

what is thought to be at the center of the milky way (our galaxy)?

Answer 2

a black hole (also known as the galactic center)

Question 3

how long ago was our solar system formed?

Answer 3

our solar system was formed 4.6 billion years ago

Question 4

what is the solar system?

Answer 4

the solar system is any object that is bound by gravity to a sun.

Question 5

name 4 objects that are in the solar system?

Answer 5

any 4 from:

• one star - the sun
• 8 planets
• natural satellites called moons that orbit planets
• dwarf planets
• comets
• asteroids
• satellites
• dust, ice and rocks make up the remaining mass

Question 6

what are artificial satellites?

Answer 6

man made objects that are put into space, for example, ISS

Question 7

what is nebula?

Answer 7

a nebula is dust and gas clumped together

Question 8

what force pulls dust and gas together to form a star (the sun)?

Answer 8

gravitational attraction

Question 9

what do fusion reactions (joining) lead to?

Answer 9

fusion reactions lead to an equilibrium between the gravitational collapse of the star and the expansion of the star due to fusion energy

Question 10

the sun, like all stars, releases energy through _______ ______ reactions in the core.

Answer 10

nuclear fusion

Question 11

what two isotopes of hydrogen are used in nuclear fusion?

Answer 11

deuterium and tritium are involved in nuclear fusion

Question 12

explain the process of nuclear fusion in stars?

Answer 12

two isotopes of hydrogen (deuterium and tritium) are forced together under high temperatures and pressure. nuclear fusion occurs to form helium and a neutron.
a tiny amount of mass is converted into a large amount of energy, which is why stars emit a lot of energy.

Question 13

the heat produced in the fusion process make the star ______ through thermal pressure.

Answer 13

expand

Question 14

_____________ __________ is pulling the mass of the star inwards.

Answer 14

gravitational attraction

Question 15

how does a star remain stable?

Answer 15

as long as the inward force of gravity is the same as the outward force generated by fusion the star remains stable

Question 16

a _________ ______ occurs at the end of a red giant’s life.

Answer 16

planetary nebula

Question 17

what happens when a red giant collapses?

Answer 17

when a red giant collapses, its outer layers shed off and what remains is a white dwarf

Question 18

what is a white dwarf?

Answer 18

a white dwarf is a very hot, dense star

Question 19

what is a black dwarf?

Answer 19

a black dwarf is a hypothetical star, created when a white dwarf cools so it no longer emits heat or light.

Question 20

why do scientists believe that there aren’t any black dwarfs?

Answer 20

the time required for a white dwarf to become a black dwarf is around 13.7 billion years.

Question 21

what is the different between stars and ‘giant’ stars?

Answer 21

‘giant’ stars are brighter and larger.

Question 22

after hydrogen has been used up in the core of a giant star, it becomes a ___ __________

Answer 22

red supergiant

Question 23

what is the death of a large star called?

Answer 23

a supernova

Question 24

how are supernovae formed?

Answer 24

• in the core of a red supergiant, lighter elements fuse to form iron
• iron nuclei absorb energy when they fuse and so the process slows down
• decreased pressure in the core means the outer layers aren’t held up and they collapse inwards which sets off an explosion

Question 25

the longest, most stable period of a star’s life is called a ____ ________ ____ .

Answer 25

main sequence star

Question 26

how is a redgiant formed?

Answer 26

• whilst hydrogen converts to helium it creates heat and light*
• • a star expands as it grows old
• • as the core runs out of hydrogen and then helium the core contracts
• • the other layers expand thus becoming cooler and less bright, forming a redgiant

Question 27

place these in order of life cycle of a star:
protostar
red super giant
supernova
nebula
black hole
main sequence star
neutron star

Answer 27

nebula
protostar
main sequence star
red super giant
super nova
neutron star or black hole