GCSE PhysicsAQA, Edexcel and OCR
10 physics questions on space physics. Pick your answer, then tap to see if you were right and why. Every answer comes from the Show Working science bank, checked against the GCSE content every board in England teaches.
01 / Quiz yourselfTry it, then tap to check
Choose your answer before you open it. Then read why, so it sticks.
01 / Space physicsBoth tiers · separate only
Answer: D A star
Our solar system has one star, the Sun, with eight planets and the dwarf planets orbiting it. Moons, which are natural satellites, orbit the planets. The Sun is an ordinary star, just much closer to us than the others.
Checked against AQA GCSE Physics 8463 specification, 4.8.1.1 Our solar system
02 / Space physicsBoth tiers · separate only
Answer: C A natural satellite
Planets orbit the Sun. Moons are natural satellites that orbit planets. Artificial satellites are made by people and launched into orbit, usually around the Earth. All of them are kept in orbit by gravity.
Checked against AQA GCSE Physics 8463 specification, 4.8.1.3 Orbital motion, natural and artificial satellites
03 / Space physicsBoth tiers · separate only
Answer: D Gravity
Gravity provides the force that keeps planets in orbit around the Sun, and moons and artificial satellites in orbit around planets. Without it they would move off in straight lines.
Checked against AQA GCSE Physics 8463 specification, 4.8.1.3 Orbital motion, natural and artificial satellites
04 / Space physicsHigher only · separate only
Answer: B Its velocity
Gravity pulls an orbiting planet towards the centre of its orbit, at right angles to its motion. This changes the direction of motion but not the speed. Velocity has a direction, so the velocity changes and the planet is accelerating.
Checked against AQA GCSE Physics 8463 specification, 4.8.1.3 Orbital motion, natural and artificial satellites
05 / Space physicsHigher only · separate only
Answer: A The one in the smaller orbit
Closer in, gravity pulls harder, so an object must move faster to stay in a stable circular orbit. So if the speed of an orbiting object changes, the radius of its orbit must change too: smaller orbits go with higher speeds.
Checked against OCR Gateway Physics A J249 specification, P8.3f and g Beyond Earth
06 / Space physicsBoth tiers · separate only
Answer: D Gravity
The Sun formed from a cloud of dust and gas pulled together by gravity. As the cloud collapsed it got hotter until hydrogen nuclei at the centre were moving fast enough to fuse into helium, releasing energy. Gravity started the collapse; fusion came after.
Checked against OCR Twenty First Century Physics B J259 specification, P6.5 How can scientific models help us understand the Big Bang?
07 / Space physicsBoth tiers · separate only
Answer: B They are balanced
In a stable star, gravity pulls everything inwards while the energy released by fusion makes the star push outwards. The two are in balance (equilibrium), so the star stays the same size for a very long time.
Checked against AQA GCSE Physics 8463 specification, 4.8.1.1 Our solar system
08 / Space physicsBoth tiers · separate only
Answer: A An increase in the observed wavelength of light
When a galaxy moves away from us, the light we receive from it has a longer wavelength and lower frequency than the light it gave out: it is shifted towards the red end of the spectrum. This is red-shift.
Checked against AQA GCSE Physics 8463 specification, 4.8.2 Red-shift
09 / Space physicsBoth tiers · separate only
Answer: C Bigger red-shift, so they move away faster
Light from most distant galaxies is red-shifted, and the further away a galaxy is, the bigger its red-shift, so the faster it is moving away. This change of speed with distance is evidence that space itself, the universe, is expanding.
Checked against AQA GCSE Physics 8463 specification, 4.8.2 Red-shift
10 / Space physicsBoth tiers · separate only
Answer: B A very small, extremely hot and dense region
If the universe is expanding, then going back in time everything was closer together. This supports the Big Bang theory: the universe began from a very small region that was extremely hot and dense, and has been expanding ever since.
Checked against AQA GCSE Physics 8463 specification, 4.8.2 Red-shift
02 / Longer answersMarked by levels
Write your answer first, on paper. Then open it and tick off the points you made. How 6-mark questions are marked.
6 marks / How the Sun formed and stays stableBoth tiers · separate only
The Sun formed from a huge cloud of dust and gas called a nebula. Gravity pulled the dust and gas together, so the cloud slowly collapsed and became denser. As it collapsed it became hotter, especially at the centre. Eventually the centre became so hot and dense that hydrogen nuclei began to fuse together to form helium nuclei. Once nuclear fusion started, the Sun became a star. Fusion releases a large amount of energy, which keeps the core very hot, and the hot gas pushes outwards, tending to make the star expand. At the same time, gravity pulls all the material of the star inwards, tending to make it collapse. In a stable star these two effects are balanced: the outward force caused by the energy from fusion is equal to the inward force of gravity, so the star is in equilibrium and does not grow or shrink. The Sun has enough hydrogen in its core for fusion to continue at a steady rate for billions of years, so it stays a stable size throughout this main sequence stage of its life.
Answers often say fusion made the cloud collapse, or that gravity is bigger than the outward force in a stable star. Gravity causes the collapse, and in a stable star the two forces are balanced.
6 marks / Red-shift and the Big BangBoth tiers · separate only
When astronomers look at the light from distant galaxies, they find that the dark lines in the spectrum are shifted towards the red end compared with light from the same elements measured on Earth. This means the wavelengths of the light are longer, which is called red-shift. The light is red-shifted because the galaxies are moving away from us. Observations show that the further away a galaxy is, the greater its red-shift. This means that the more distant a galaxy is, the faster it is moving away from us. This pattern is what we would expect if space itself is expanding, carrying the galaxies further apart, so red-shift is evidence that the universe is expanding. If the universe is getting bigger now, then in the past it must have been smaller. Tracing this back, all the matter in the universe would have started from a very small region that was extremely hot and dense. This idea is the Big Bang theory, so red-shift provides evidence that supports it.
Red-shift means the observed wavelength gets longer, not shorter, and it is not that the galaxy itself is red. Make the link from “further away, moving away faster” to an expanding universe, then to the Big Bang.
03 / In the appComing to Show Working
In the app, choose your exam board and course and you only see what your board asks for. Tap through questions, or open Read the answers to see every answer in the topic at once, covered until you tap. Science is coming to the app soon.
Coming soon to the App StoreOur own questions, written for every board. Show Working is independent and not affiliated with any exam board.
Show WorkingComing soon to the App Store
Show Working