Starter quiz
- How do planets differ from a star?
- planets emit light radiation
- planets are often rocky or have a rocky core ✓
- planets orbit the Sun ✓
- planets are spherical
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- What is a comet?
- an icy rock pulled towards the Sun from beyond Pluto ✓
- a rock pulled towards the Sun from the Asteroid Belt
- an icy rock pulled towards the Sun from the orbit of a gas giant planet
- a burning rock falling through Earth's atmosphere
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- How can we reduce the amount that stars twinkle when we observe them?
- by not looking at them through anything with a glass lens
- by using a telescope with a large mirror
- by standing on top of a very high mountain ✓
- by looking on a completely clear night with no high clouds
- we cannot reduce how much stars twinkle
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- Approximately how many stars are there in the Milky Way galaxy?
- 300 (three hundred)
- 300 000 (three hundred thousand)
- 300 000 000 (three hundred million)
- 300 000 000 000 (three hundred billion) ✓
- 300 000 000 000 000 (three hundred trillion)
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- The speed at which a galaxy is moving away from us can be calculated from its ______.
- 'redshift' ✓
- What absorbs particular frequencies of light to create absorption lines in light from a distant star?
- extremely hot gases in the star's core
- cooler gases in the star's outer layers ✓
- nebulae between us and the star
- Earth's atmosphere
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Exit quiz
- Messier objects were first seen in the 17th century, using newly invented telescopes. In what ways is a Messier object different to a star?
- they are fainter than stars ✓
- they are larger than stars ✓
- they are smaller than stars
- they are fuzzier than stars ✓
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- What is used to measure the distance to a distant galaxy?
- a variable star of changing brightness within the distant galaxy ✓
- a variable (distant) galaxy of changing brightness
- the redshift of the distant galaxy
- the redshift of a star within the distant galaxy
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- What is the relationship between the movement of galaxies and their distance from us?
- the further away from us they are, the faster they are moving through space ✓
- the further away from us they are, the faster they are orbiting around us
- the further away from us they are, the faster they are moving away from us ✓
- the further away from us they are, the faster they are moving towards us
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- According to the Big Bang Theory, where was all matter about 13.7 billion years ago?
- spread out much further than it is today
- in much the same place as it is today
- all in the same, very small place ✓
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- What best describes the Big Bang?
- a contraction
- an expansion ✓
- an explosion
- an implosion
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- Spiral galaxies are spinning faster and the universe is expanding more quickly than our current understanding has predicted. What ideas might explain what is going on and improve our understanding?
- dark energy ✓
- dark force
- dark matter ✓
- dark power
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Worksheet
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Lesson Details
Key learning points
- Light from nearly all galaxies is redshifted, showing they're moving away, with distant galaxies receding faster.
- Evidence shows that galaxies were all in the same place about 14 billion years ago, showing their movement apart since.
- The Big Bang Theory suggests that the universe began from a very small region that was extremely hot and dense.
- A scientific theory is our best understanding based on all evidence and is subject to rigorous testing.
- We do not fully understand dark matter or dark energy.
Common misconception
The Big Bang was an explosion in which existing matter blew up.
Describe the Big Bang as an expansion of space combined with the creation of all matter in the universe.
Keywords
Redshift - the increase in the wavelength of light (and decrease in its frequency) caused by the movement of a star or galaxy away from us
Big bang theory - the theory that the our whole universe started in a hot, dense state, then expanded and cooled over fourteen billion years
Cmbr - cosmic microwave background radiation is electromagnetic radiation produced in the hot early universe which has since been ‘stretched’ to the microwave part of the spectrum.
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