AQA GCSE 1b-7 The Universe. AQA GCSE Physics pages 106 to 115 AQA GCSE Science pages 310 to 319. April 10 th , 2010. AQA GCSE Specification. THE UNIVERSE 11.7 What do we know about the origins of the Universe and how it continues to change?
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AQA GCSE Physics pages 106 to 115
AQA GCSE Science pages 310 to 319
April 10th, 2010
11.7 What do we know about the origins of the Universe and how it continues to change?
Using skills, knowledge and understanding of how science works:
• to compare and contrast the particular advantages and disadvantages of using different types of telescope on Earth and in space to make observations on and deductions about the universe.
Skills, knowledge and understanding of how science works set in the context of:
• If a wave source is moving relative to an observer there will be a change in the observed wavelength and frequency.
• There is a red-shift in light observed from most distant galaxies. The further away galaxies are the bigger the red-shift.
• How the observed red-shift provides evidence that the universe is expanding and supports the ‘big bang’ theory (that the universe began from a very small initial point).
• Observations of the solar system and the galaxies in the universe can be carried out on the Earth or from space.
• Observations are made with telescopes that may detect visible light or other electromagnetic radiations such as radio waves or X-rays.
As the ambulance travels forwards:
The sound wave in front is compressed
- decreasing its wavelength
- increasing its frequency
The sound wave behind is stretched out:
- increasing its wavelength
- decreasing its frequency
ambulance sound demo
The Doppler Effect, discovered in 1842 by Christian Doppler, also occurs with light waves.
With light waves:
In front of the moving object
decreasing wavelength and increasing frequency
makes the light BLUER
- known as BLUE SHIFT
Behind the moving object
increasing wavelength and decreasing frequency
makes the light REDER
- known as RED SHIFT
In 1929 Edwin Hubble discovered that the light from distant galaxies was red-shifted.
He found that the red shift was proportional to the distance to a distant galaxy.
Therefore the more distant a galaxy is away from us the faster it is moving away from us.
Note: Hubble’s observations, and many more since, only apply to DISTANT GALAXIES. Some near by ones, for example the Andromeda Galaxy, are moving towards us.
Hubble’s observations tell us that distant galaxies are receding from us and that the further they are away the faster they are moving away from us.
Hence the Universe is expanding.
Balloon model of the expanding Universe
The space between the galaxies expands and so the galaxies grow further apart
When a wave source is _______ away from an observer the wave emitted is spread out. This is called the _______ Effect and with light it is a cause of ________.
Distant galaxies show red-shift that _________ with their distance away. More distant ________ are therefore moving away from us with ________ speeds.
The red-shit shown by _______ galaxies is evidence that the Universe is _________.
Red Shift - eChalk
Doppler Effect - Sound with microphone
Doppler Effect - Iona
Doppler Effect - Explore Science
Doppler Effect (Quick Sound Demo) - Iona
Doppler effect - NTNU
Doppler effect - ambulance - Fendt
Doppler Shift with light - eChalk
Doppler Shift with sound - eChalk
Doppler Shift with sound effects- eChalk
Red Shift - eChalk
Introduction Page to AQA Origin of the Universe
Evidence of the Big Bang including Red Shift - includes applet showing the affect of expansion on wavelengthSimulations
Because they are so far away.
It is blue-shifted because its wavelength is reduced.
2. (a) Earth, Sun, Andromeda galaxy, Universe.
(b) (i) Planet, star. (ii) Red-shift, galaxyThe expanding Universe ANSWERS
The Big Bang theory is an explanation for the origin of the Universe. It states that:
The latest observations indicate that the Big Bang took place about 13 500 million years ago.
This theory was not generally accepted until 1965 before which an alternative explanation for the expansion of the Universe called the ‘Steady State theory’ was dominant. In this theory new matter is continually created in the gap left as the Universe expands.
This radiation was first detected by Penzias and Wilson in 1965.
The Big bang produced very short wavelength gamma rays.
As space has expanded these rays have been stretched our so much that they now have the much longer wavelengths of microwaves.
The presence of this radiation throughout the Universe is evidence that supports the Big Bang theory.
The Big Bang theory is an explanation for the _______ of the Universe. According to this theory all space, matter and _____ were created from an exploding very small _______ nearly 14 billion years ago.
Since this time the Universe has been _________ causing the initial _______ rays produced at the Big Bang to have spread out to become __________. The detection of this _________ radiation in 1965 led astronomers to ________ the previous Steady State theory.
Expanding Universe - 7stones
Expanding Universe - eChalk
Age of the Universe - eChalk
Big Bang Time Machine - School Science
Introduction Page to AQA Origin of the Universe
The Big Bang
Evidence of the Big Bang including Red Shift - includes applet showing the affect of expansion on wavelength
Test bite on the Origin of the UniverseSimulations
It will be stretched even more to longer wavelengths.
The expansion might reverse or it might just gradually stop.
2. (a) The Universe will continue to expand.
(b) The expansion will stop and reverse.The Big Bang ANSWERS
Jodrell Bank Radio Telescope
The Hubble Space TelescopeLooking into space
Observations of the solar system and the galaxies in the universe can be carried out on the Earth or from space.
Observations are made with telescopes that may detect visible light or other electromagnetic radiations such as radio waves or X-rays.
The Mount Palomar telescope in California, with an objective mirror of 5m (200 inches), was for many years the world’s largest telescopeOptical (visible light) telescopes
Optical telescopes use a concave mirror or a convex lens to collect light from distant objects.
The greater the size of the mirror or lens:
- the more detail seen in the image produced.
The structure of the Milky Way can be studied using radio waves as these waves are able to travel through gas clouds where visible light cannot. Our knowledge of what is at the centre of our galaxy has been obtained primarily by using radio telescopes.
The bigger the telescope, the more detail it can map out and the further away it can detect radio sources.Radio telescopes
- It scatters the light from space objects and makes their images fuzzy.
- It stops most microwaves, infra-red, ultra-violet, X-ray and gamma ray radiation.
Satellites telescopes are not affected by the Earth’s atmosphere.
Objects such as exploding stars and black holes can be studied with such telescopes.
Also far more detailed optical images can be obtained.
The Hubble Space TelescopeSatellite telescopes
Many of the most spectacular modern images are in fact composites images taken of a number of regions of the electromagnetic spectrum.
The picture below of the Whirlpool Galaxy is such an example taken by the Hubble Space Telescope. It is of the galaxy taken with ultra-violet and infra-red as well as with visible light.
They require rockets, for example the Space Shuttle, to be deployed – this is very expensive and dangerous.
They are very difficult to maintain if something goes wrong or wears out.
They are very difficult to update as technology advances.Question
Telescopes are used to observe objects in ______.
There are ___________ for all regions of the electromagnetic _________ as some objects cannot be observed using ______ light only. For example the main evidence supporting the existence of _________ holes comes from the observation of X-rays.
Satellites have been used in recent years as they do not have the disadvantage of ___________ distortion or being dependent on _________ conditions.
A shooting star.
The telescope collects more light from a star than the unaided eye does. So stars too faint to be seen with the unaided eye can be seen with a telescope.
HST is in space above the atmosphere.
The infra-red radiation is absorbed by the molecules of the gases in the atmosphere.
(a) Light, radio waves.
(b) Gamma rays, infra-red radiation.
2. (a) Light from objects in space has to pass through the Earth’s atmosphere to reach ground-based telescopes. The Earth’s atmosphere scatters the light slightly and ‘smudges’ the images out. HST is above the Earth’s atmosphere, so its images aren’t affected.
(b) Gamma rays can’t pass through the atmosphere, so the detectors need to be above the atmosphere whereas radio waves can pass through the atmosphere.
(c) (i) Massive exploding stars.
(ii) Planets beyond the solar system.Looking into space ANSWERS