Topic 6 - Astronomy, Stars, The Universe & The Big Bang Theory

Question 1

More than 2000 years ago the Earth was believed to be at the centre of the universe. The planets, the Moon and the Sun were believed to be in orbit around the Earth.
In 1543 Nicolaus Copernicus proposed that the Earth was a planet, and that the Earth and
the other planets orbit around the Sun.
Discuss how evidence has changed our views of the universe. (6)

Answer 1

• idea that telescopic evidence supported the heliocentric model e.g. observing the moons of Jupiter supported a sun-centred solar system
• detail e.g. it was Galileo’s observations of the moons of Jupiter
• the moons rotate around Jupiter i.e. not everything rotates about the earth
• other observations by telescope - discoveries of the planets Uranus and Neptune + the asteroid belt
• (detailed) photographic evidence
• use of computer modelling
• satellite observations
• heliocentric model verified by Voyager missions (space probes)

Question 2

The Big Bang theory is one theory for the origin of the Universe.
The Big Bang theory suggests:
• the Universe had a beginning
• the Universe is still expanding.
The Steady State theory is also a theory about the origin of the Universe.
Give 1 similarity and 1 difference when comparing the Big Bang theory with the Steady
State theory. (2)

Answer 2

Both have expanding universe (1)
In steady state, universe has no beginning (1)
Steady state theory requires the continual formation of new matter, the Big Bang theory does not (1)

Question 3

Saturn is a ……………….. .
The Moon is a …………. .
Halley’s Comet orbits a …………….. .
(3)

Answer 3

Planet (1)
Satellite (1)
Star (1)

Question 4

An astronomer observes light from a distant galaxy.
As the galaxy moves away from us, the spectrum of the light is (1)
A blue-shifted
B green-shifted
C red-shifted
D violet-shifted

Answer 4

red-shifted

Question 5

The shift in the spectrum of light from the distant galaxy provides evidence for the
expansion of the (1)
A Earth
B Milky Way Galaxy
C Solar System
D Universe

Answer 5

Universe

Question 6

The Big Bang theory is one theory for the origin of the Universe. It suggests:
• the Universe had a beginning
• the Universe is still expanding.
Which of these provides evidence that the Universe had a beginning?
(1)
A the discovery of other galaxies
B the discovery of the moons of Jupiter
C the discovery of planets orbiting distant stars
D the discovery of cosmic microwave background (CMB) radiation

Answer 6

the discovery of cosmic microwave background (CMB) radiation

Question 7

The Big Bang theory gives an explanation for the origin of the Universe.
Explain how evidence supports the ideas that
• the Universe is expanding
• the Universe began at a single point. (6)

Answer 7

evidence for expansion:
• red shift
• light from distant galaxies/stars
• shifted to red side of em spectrum
• (observed) wavelength of light is longer
• showing source moving away
• (nearly) all galaxies show this
• Doppler effect
• (expanding at an increasing rate / dark energy)
evidence for beginning at a point:
• CMBR
• microwave radiation left over from beginning • the increase of recessional velocities with distance (extrapolating)
• microwaves because of cooling
• detected from all over the sky

Question 8

The Big Bang theory suggests:
• the Universe had a beginning
• the Universe is still expanding.
Evidence that the Universe is still expanding comes from observations of light from distant
galaxies.
Describe how light from distant galaxies shows that the Universe is still expanding. (2)

Answer 8

Wavelength (of the light) (1)
Appears to increase (1)

Question 9

Any object weighs less on the Moon than it does on the Earth.
The gravitational field strength on the Moon is different from the gravitational field strength
on the Earth.
Suggest 2 reasons why the gravitational field strength on the Moon is different from the
gravitational field strength on the Earth. (2)

Answer 9

Mass (1)
Radius (1)
Density (1)

Question 10

A long time ago, scientists believed that the Earth was at the centre of the Solar System.
Evidence has since proved that the Sun is at the centre of the Solar System.
State one other idea about the Solar System that has changed over time. (1)

Answer 10

Planets have moons (1)
The earth rotates (1)
Planets orbit the sun (1)
Pluto is no longer a planet (1)
Orbits are elliptical, not circular (1)
There are more planets than previously thought (1)
Ours is not the only solar system (1)
Earth is round/not flat (1)

Question 11

Satellites are used to gather data about the origin of the Universe.
The Big Bang theory is a theory about the origin of the Universe.
Evidence for the Big Bang theory is provided by red-shift and CMB radiation.
Describe what is meant by red-shift. (2)

Answer 11

Wavelength increased/frequency decreased (1)
As the star moves away from us (1)

Question 12

Explain how red-shift provides evidence for the Big Bang theory. (2)

Answer 12

Big bang has expanding universe (1)
With galaxies moving away from each other (1)

Question 13

The Cosmic Background Explorer (COBE) satellite observed CMB radiation from 1989
to 1993.
State what the ‘M’ in CMB radiation stands for. (1)

Answer 13

Microwave

Question 14

State what is meant by ‘cosmic background radiation’. (1)

Answer 14

Radiation that comes from the universe/all over the sky (1)

Question 15

Explain how the presence of CMB radiation provides evidence for the Big Bang theory. (2)

Answer 15

The Big Bang bang has a beginning/initial explosion (1)
That releases energy (1)

Question 16

Stars may originate as a nebula.
Describe the process that then occurs to produce the conditions necessary for nuclear fusion in a new star. (3)

Answer 16

Nebula collapses (1)
Under gravity (1)
Very high temperatures/pressures (1)
GPE converted to KE (1)

Question 17

A nebula may evolve into a main sequence star, such as the Sun.
Explain how a nebula may evolve into a main sequence star. (3)

Answer 17

Nebula as a cloud of gas/dust (1)
Gas/atoms pulled together (1)
By gravitational force (1)
Temperature increases (1)
Hot enough for nuclear fusion (1)

Question 18

Herschel and Hubble were astronomers who have had telescopes named after them. The telescope named after Herschel detects infrared radiation.
Herschel is a suitable name for this infrared telescope because (1)
A Herschel discovered Uranus using a telescope
B Herschel constructed over 400 telescopes
C Herschel discovered infrared radiation
D Herschel constructed this telescope

Answer 18

Herschel discovered infrared radiation

Question 19

Explain why the distance between the Moon and the Hubble telescope changes. (2)

Answer 19

Change of relative positions in orbits (1)
Different radii orbits (1)
Different orbital speeds (1)

Question 20

Hubble’s work led to the theory of the Big Bang.
Describe what is meant by the Big Bang theory. (2)

Answer 20

Expansion of space (1)
Continuing expansion (1)
From very hot/dense start (1)
From a point/small volume (1)
Original of universe (1)

Question 21

Describe how a reflecting telescope forms an image of a distant object. (2)

Answer 21

Mirror (1)
Which is converging (1)

Question 22

Both telescopes use a converging lens as an eyepiece.
State what the eyepiece of a telescope is intended to do to the image. (1)

Answer 22

Magnifies

Question 23

A long time ago, astronomers thought that the Earth was the centre of the Universe.
This was called the geocentric model.
The evidence for this model came from observations of the sky using the naked eye.
After the telescope was invented, astronomers quickly gathered evidence which showed that the geocentric model is not correct.
Describe the evidence both for the geocentric model and against the geocentric model. (6)

Answer 23

evidence for:
• idea of Sun, Moon, stars or planets moving across the sky (not just orbiting)
• in the same direction
• pattern is repeated
• appear to be going around the Earth
• same every day
evidence against:
• moons of {Jupiter/ other planet (with moons)}
• appear to {orbit/ go around} {Jupiter/ other planet}
• movement of Sun etc. not quite the same each day
• planets do not move in a simple path
• retrograde (west-east) motion of planets

Question 24

Our Sun is a main sequence star.
It will stay as a main sequence star for millions of years, continuing to radiate energy.
Our Sun was formed from a nebula.
Describe the formation of our Sun from nebula to main sequence. (2)

Answer 24

Gravity (1)
Causes the nebula to collapse (1)
Causing the temperature to increase (1)

Question 25

Our Sun will go through many stages.
Which of these stages will our Sun go through?
(1)
A a black hole
B a neutron star
C a supernova
D a white dwarf

Answer 25

a white dwarf

Question 26

A diagram shows some lines in the spectrum of light from a nearby galaxy.
Explain why you have drawn line Y in this position on the diagram (2)

Answer 26

Galaxy moving away (1)
So line shifted to longer wavelength (1)

Question 27

2 theories about the Universe are the Steady State Theory and The Big Bang Theory.
The table shows some ideas about the Universe.
Which row of the table applies to the Steady State Theory? (1)
A the Universe is not expanding + had a beginning
B the Universe is expanding + had a beginning
C the Universe is not expanding + did not have a beginning
D the Universe is expanding + did not have a beginning

Answer 27

the Universe is expanding + did not have a beginning

Question 28

State the name of the discovery that persuaded most scientists to prefer the Big Bang Theory to the Steady State Theory. (1)

Answer 28

Cosmic microwave background radiation

Question 29

Our Sun is a star.
The life cycle of a star has several stages.
The Sun is in its main sequence stage.
The next stage in the life cycle of the Sun will be
A a nebula
B a red giant
C a white dwarf
D a black hole

Answer 29

a red giant

Question 30

The galaxy which contains our Sun is called
(1)
A Andromeda
B Orion
C the Milky Way
D the Solar System

Answer 30

the Milky Way

Question 31

Which of these is furthest from the Sun?
(1)
A Earth
B The Moon
C The planet Jupiter
D The star Proxima Centauri

Answer 31

The star Proxima Centauri

Question 32

Scientists search for signs of life on the planet Mars.
Describe one method they use to search for signs of life on the planet Mars. (2)

Answer 32

Telescope (1)
Has camera/takes photos (1)

Lander (1)
Collects samples (1)

Question 33

Scientists search for new planets orbiting distant stars.
The photograph shows the Kepler space telescope.
The Kepler space telescope records the brightness of light from distant stars.
When a planet passes in front of a distant star, there is a tiny dip in the brightness of the light from the star.
Many telescopes are used on the Earth but the Kepler space telescope orbits above the Earth’s atmosphere.
Explain why telescopes that search for planets are not on the Earth’s surface. (2)

Answer 33

On earth, image isn’t bright enough/distorted (1)
Planets very small far away (1)
Light pollution (1)
Can detect different parts of em spectrum that can’t be detected on earth (1)
Can keep it pointed at the same spot easily (1)

Question 34

The Kepler space telescope was pointed towards one star.
It detected the same dip in the brightness of the star every 150 days.
Suggest what information this gives about the planet that orbits this star. (1)

Answer 34

Planet takes 150 days to orbit the star

Question 35

A star of much greater mass than the Sun will eventually become (1)
A a black hole
B a protostar
C a red dwarf
D a white dwarf

Answer 35

a black hole

Question 36

Describe how the Sun reached its main sequence stage. (3)

Answer 36

In a nebula (1)
Particles attracted by force of gravity (1)
Pe/KE transferred to thermal energy (1)
Until hot/dense enough for nuclear fusion (1)

Question 37

Scientists can estimate the age of a star. They want to find the age of the oldest star.
Suggest why knowing the age of the oldest star is not enough to tell scientists the age of the Universe. (2)

Answer 37

The oldest star had not yet appeared when the Big Bang started (1)
Star takes time to form (1)
Can’t be certain of this time (1)
Universe is older than the oldest star (1)

Question 38

Edwin Hubble discovered that the Universe was expanding.
He did this by using observations of red-shift.
Explain what red-shift is and how it provides evidence that the Universe is expanding. (6)

Answer 38

• light shifted to red end of spectrum
• light waves are stretched so wavelength increases
• reference to black or spectral lines moving to ‘red end’ (of absorption spectrum)
• frequency of wave from a moving source changes
• decrease in frequency means source moving away
• increase in frequency means source moving towards us
• red shift shows galaxies are moving away from us
• greater red shift indicates galaxy moving away faster
• further away galaxies give greater red shift
• (nearly) all galaxies show red-shift
• red shift shows decrease in frequency
• blue shift shows increase in frequency
• therefore galaxies are moving apart
• [mention of Doppler effect]
• [outline of Doppler effect]