Unit 1: Theme 1 Flashcards
What are telescopes used for?
To observe stars and other distant objects.
How do telescopes work?
Collect light and make it into a brighter, bigger image.
What are the advantages of a ground-based telescope? (2)
- Can be updated, maintained and visited easily.
* Cheaper
What are the advantages of a space-based telescope?
• Clearer image -> No atmosphere or light pollution
What waves do some stars and planets emit?
Radio waves
What waves do newly formed stars and dust clouds emit?
Microwaves
What waves do ground-based telescopes detect? (3)
- Visible light
- Radio waves
- Microwaves
(These all pass through the atmosphere.)
What waves do space-based telescopes detect? (5)
- Visible light
- Infrared radiation
- Ultraviolet radiation
- X-Rays
- Gamma rays
What do space probes do?
Travel through solar system -> Land on planets -> Send back data
What is the Doppler effect?
Waves from objects moving away appear to stretch.
What has a longer wavelength, red or blue light?
Red
What is red-shift and how does it work?
Object moves away -> Light wavelengths are stretched -> Waves appear more red (because red has longer WL) -> Object appears red
What waves do space-based telescopes detect? (5)
- Visible light
- Infrared radiation
- Ultraviolet radiation
- X-Rays
- Gamma rays
What do space probes do?
Travel through solar system -> Land on planets -> Send back data
What is the Doppler effect?
Waves from objects moving away appear to stretch.
What has a longer wavelength, red or blue light?
Red
What is red-shift and how does it work?
Object moves away -> Light wavelengths are stretched -> Waves appear more red (because red has longer WL) -> Object appears red
How does red-shift show which galaxies are moving away faster?
Galaxies that are moving away faster must have a greater red-shift effect.
How do we know that the universe is expanding?
Galaxies are moving away from the earth in all directions.
What was the Big Bang?
The theory that about 14 billion years ago all matter was once squashed into a tiny place and then a huge expansion began.
What is cosmic background radiation?
- Weak microwave signal
- Arriving at earth from all directions
- Remains of radiation from BB
What is a star?
A ball of immensely hot, glowing gas.
What is a planet’s path around a star called?
Orbit
2000 years ago, what did people think the solar system looked like?
- Earth, Moon and stars orbited a ‘central fire’
OR - Sun, Moon and planets orbited the Earth
What shape is an orbit?
An ellipse (squashed circle).
Name the planets in order.
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
What was the Big Bang?
The theory that about 14 billion years ago all matter was once squashed into a tiny place and then a huge expansion began.
What is cosmic background radiation?
- Weak microwave signal
- Arriving at earth from all directions
- Remains of radiation from BB
What is a star?
A ball of immensely hot, glowing gas.
What is a planet’s path around a star called?
Orbit
2000 years ago, what did people think the solar system looked like?
- Earth, Moon and stars orbited a ‘central fire’
OR - Sun, Moon and planets orbited the Earth
What shape is an orbit?
An ellipse (squashed circle).
Name the planets in order.
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
What is a mnemonic for remembering the order of the planets?
My (Mercury) Very (Venus) Excellent (Earth) Mother (Mars) Just (Jupiter) Served (Saturn) Us (Uranus) Nipples (Neptune)
OR
My (Mercury) Very (Venus) Easy(Earth) Method (Mars) Just(Jupiter) Speeds(Saturn) Up (Uranus) Naming (Neptune)
What is our galaxy called?
Milky Way
Why is it likely that there are other planets in our galaxy that can sustain life?
Because there may be other planets that can sustain liquid water, which is necessary for life to develop.
What was the Earth like when it first formed?
A molten ball
What happened when the molten Earth began to cool?
The heavier materials sank and the lighter ones rose.
How do geologists learn about the structure of the Earth?
Studying the vibrations caused by earthquakes.
Describe the structure of the Earth, from centre to the outside.
Inner Core Outer Core Mantle Crust Atmosphere
What metals is the core made from?
Iron and Nickel
What causes convection currents?
Nuclear reactions deep in the Earth heat up the mantle.
What causes tectonic tiles to move?
Convection currents
What happens when one plate slips under another?
It melts and the molten rock rises back to the surface, forming a volcano.
What can happen when two plates slip past each other?
Strong forces can build up and a sudden slip can cause an earthquake.
Are earthquakes easy to predict?
No, but scientists are making advances.
What was the earth’s early atmosphere like?
- Gases released by volcanoes
- Mainly CO2
- Almost no oxygen
- Bit of water vapour, ammonia, hydrogen and methane
How did oceans form?
The water vapour cooled and condensed.
How did life appear on earth?
The mixture of gases on the planet created amino acids - the molecules of life.
How did oxygen form on earth?
The early plants and algae formed it through photosynthesis.
What are the main gases in today’s atmosphere?
- Nitrogen and oxygen
- Small amounts of carbon dioxide and water vapour
- Traces of gases such as argon
What do greenhouse gases do?
Trap energy in the atmosphere.
What happens to waves from the sun when they hit the Earth?
The energy is in the form of SHORT-WAVE RADIATION and INFRARED. The Earth then emits this in the form of LONG-WAVE RADIATION (INFRARED) which is absorbed by greenhouse gases. This warms the atmosphere.
Are greenhouse gases good for the Earth?
They keep the Earth warm enough for life, but too much GH gases can cause global warming and extreme changes to weather patterns. This is called CLIMATE CHANGE.
