P8 -Space physics

Question 1

definition : the big bang theory

Answer 1

It suggests that the universe has expanded from an initially very SMALL, HOT and DENSE point.

Question 2

DEFINITION : dark matter

Answer 2

A hypothesised type of mass that cannot be observed by current
methods. It is used to explain why some galaxies rotate faster than they should for
their observed mass

Question 3

DEFINITION : dark energy

Answer 3

A hypothesised form of energy, believed to be responsible for the
universe’s ever increasing rate of expansion.

Question 4

DEFINITION : Main sequence star

Answer 4

The stable state of all stars. The gravitational forces

pulling the star together, and the pressure pushing outwards, are balanced.

Question 5

DEFINITION : Nebula

Answer 5

A cloud of dust and gas.

Question 6

DEFINITION : protostar

Answer 6

The first stage all stars go through after forming from a nebula. In this
stage the star becomes hot enough for hydrogen nuclei to fuse.

Question 7

DEFINITION : red giant star

Answer 7

When their hydrogen is used up and larger nuclei are produced
by fusion (stars of a similar magnitude to the Sun) will expand to form a red giant.

Question 8

DEFINITION : red-shift

Answer 8

Red-Shift: The observed increase in the wavelength of the light emitted by
distant galaxies. The more distant the galaxy, the faster it is moving and so the
bigger the observed increase in wavelength.

Question 9

DEFINITION : supernova

Answer 9

The EXPLOSION of a MASSIVE star, that distributes the elements
created by the fusion reactions in the star, throughout the universe.

Question 10

DEFINITION : white dwarf

Answer 10

When the FUSION reactions in stars (of a similar magnitude to the sun)
come to an END, the star will CONTRACT under gravity and COOL down to form a white dwarf.

Question 11

CLASS NOTES: Order of planets

Answer 11

My Very Evil Mother Just Served Us Noodles
Mercury 
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 12

CLASS NOTES: why is pluto a dwarf planet?

Answer 12

• It’s obit cuts into neptunes orbit
• its orbit is not a circle
• pluto is small (about the size of USA)

Question 13

CLASS NOTES: What stops a star from collapsing?

Answer 13

Forces.
Gravity acting inwards.
Pressure from fusion pressing outwards.

Question 14

CLASS NOTES: Lifecycle of a star

Answer 14

Nebula
Protostar
main sequence star
Red super Giant |||||||| Red Giant
Supernova |||||||| White dwarf
Neutron star |||||||| Black dwarf

Question 15

CLASS NOTES: Creation of elements

Answer 15

Hydrogen and Helium - made shortly after the big bang.

HELIUM in stars - Created in MAIN SEQUENCE STAR with the P-P chain

Elements up to IRON - Made in MASSIVE STARS during their Giant phase.

Elements up to URANIUM - Made during SUPERNOVA explosions.

Elements above uranium - created by human beings in experiments.

Question 16

CLASS NOTES: summary of red shift and big bang theory

Answer 16

• The absorption lines of distant galaxies are redshifted.
• They must all be moving further away from us.
• The further away they are, the faster they are moving away.
• The universe is expanding.
• The universe must have been smaller, hotter and denser in the past.

Question 17

EXAM PRACTISE : what is a red shift?

Answer 17

wavelength (of light) increases

accept frequency decreases
or
light moves to red end of spectrum
accept redder but do not accept red alone

Question 18

EXAM PRACTISE : What does the measurement of the biggest red-shift tell scientists about this star?

Answer 18

it is the star (detected) furthEST  from the
Earth
accept galaxy for stars
or
it is moving away the fastEST

Question 19

EXAM PRACTISE: Describe the ‘big bang’ theory.

Answer 19

all matter compressed from a single point (1)

massive) explosion SENDS matter outwards (1

Question 20

EXAM PRACTISE: Explain why scientists believe that the Solar System was formed from the material produced when earlier stars exploded.

Answer 20

solar system contains heavy elements / elements heavier than hydrogen
and helium (1)
these (heavy) elements are / were formed by (nuclear) fusion (1)

(at the very high temperature(s)) in a super nova / when stars explode (1)

Question 21

EXAM PRACTISE: Explain how the spectrum ‘shift’ of the dark line supports the theory that the Universe began from a very small point.

Answer 21

line shifts towards red end of spectrum (1)
wavelength (appears) to increase (1)
galaxy is moving away (from the
Earth) (1)

Question 22

EXAM PRACTISE: Cosmic microwave background radiation (CMBR) is a type of electromagnetic
radiation. CMBR fills the Universe. It was first discovered in 1965 by two
astronomers called Penzias and Wilson.
(i) What do scientists believe is the origin of CMBR?

Answer 22

(radiation produced shortly after) ‘Big Bang’

Question 23

EXAM PRACTISE: Why was the discovery of CMBR so important to the scientists believing the ‘Big Bang’ theory to be correct?

Answer 23

any one from:
• can only be explained by ‘Big Bang’
• existence predicted by ‘Big Bang’
• provides (further) evidence for ‘Big Bang’
ignore proves ‘Big Bang’ (theory)
ignore reference to red-shift

Question 24

EXAM PRACTISE: How is the wavelength of CMBR likely to change, if at all, over the next billion years?

Answer 24

increases / universe continues to accelerate outwards/ greater red shift