This page contains the AQA GCSE Physics P16 Solar System Questions and kerboodle answers for revision and understanding .This page also contains the link to the notes and video for the revision of this topic.
P16.1 Formation of the Solar System AQA GCSE Physics P16 Space Kerboodle Answers : Page No. 233 1 a A comet cannot be seen when it is far away from the Sun because they are frozen rocks that move around the Sun in orbits that are elliptical in shape (like squashed circles). These elliptical orbits take them far away from the Sun. we only see them when they return near the Sun because then they heat up so much that they emit light. b One difference and one similarity between a comet and an asteroid are as follows. Asteroids are huge rocky objects that are mostly found in the asteroid belt between Mars and Jupiter, whereas comets are frozen balls of gas, ice and rocky material. Both asteroids and comets orbit the central star of the solar system (although the orbits of comets are highly eccentric). 2 a i the largest planet in the Solar System is Jupiter.
ii nearest the Sun planet in the Solar System is Mercury b Earth is likely to be the only planet in the Solar System where liquid water is always present on the surface. The presence of water on the surface of Earth is a product of its atmospheric pressure and a stable orbit in the Sun‘s circumstellar habitable zone, though the origin of Earth’s water remains unknown. 3 The Earth’s orbit is almost circular. Comets are frozen rocks that move around the Sun in orbits that are elliptical in shape (like squashed circles). These elliptical orbits take them far away from the Sun. You only see them when they return near the Sun because then they heat up so much that they emit light. If we happen to move close enough, the temperature on Earth would rise substantially. Suppose, we somehow are able to go underground to save ourselves (not entirely possible given our population size), we may find all water has been evaporated and we will all die of thirst. Also, at such close proximity to Sun, all the vegetation would be wiped out and thus we would see lack of oxygen to breathe. 4 a The Sun formed from dust and gas clouds in space. The Sun formed billions of years ago from clouds of dust and gas pulled together by gravitational attraction (Figure 2) All stars including the Sun form out of clouds of dust and gas. The particles in the clouds arc pulled together by their own gravitational attraction so the particles speed up. The clouds merge together and become more and more concentrated to form a protostar, which is a star-to-be. As a protostar becomes denser, its particles speed up more and collide more, so Its temperature increases and it gets hotter. The process transfers energy from the protostar’s gravitational potential energy store to its thermal energy store. If the protostar becomes hot enough, the nuclei of hydrogen atoms fuse together, forming helium nuclei. Energy is released in this fusion, so the protostar gets honer and brighter and starts to shine. A star is born! b Main sequence star is and why the Sun is a main sequence star. Stars such as the Sun radiate energy because of hydrogen fusion in the core. They are called main sequence stars because this is the main stage in the life of a star. Such stars can maintain their energy output for millions of years until there are no more hydrogen nuclei left to fuse together. P16.2 The life history of a star AQA GCSE Physics P16 Space Kerboodle Answers: Page No. 235 1 a Protostar then main sequence then red giant and last white dwarf. b i Main sequence is the stage in the above list that the Sun is at now, ii Sun become red giant and then converted into white or black dwarf star. 2 a i Gravitational pull is the force that makes a red supergiant collapse. ii force of the radiation from nuclear fusion is the force that prevents a main sequence star from collapsing, b a white dwarf eventually becomes a black dwarf. When there are no more light elements in the core, fusion stops, and no more radiation is released. Because of its own gravity, the star collapses in on itself. As it collapses, it heats up and turns from red to yellow to white. It becomes a white dwarf. This is a hot, dense, white Star much smaller in diameter than it was before. Stars such as the Sun then fade out, go cold, and become black dwarfs. 3 a i Helium nuclei are formed when nuclei of Hydrogen are fused. ii Uranium
is formed in a supernova explosion iii Stars form nuclei of Helium and iron by fusing smaller nuclei. b Differences between a red giant star and a neutron star are Size: a red giant is 100,000,000km in radius, a neutron star is 5. Temperature and color: a red giant is less than 4,000K, and a deep red, while a neutron star is over 100,000K and an electric blue. Composition: a red giant is mainly composed of hydrogen, with an inert core of helium, carbon, oxygen and neon or silicon, while a neutron star has a thick shell of solid iron with a core of neutrons. 4 a all the uranium in the Earth has not decayed by now. Because the half life of uranium is so long (700 million year, U-238 4.5 Billion years) The earth is estimated at an age of 4.5 Billion years. So all the uranium in the earth has not decayed by now. b Plutonium-239 has a half-life of 24000 years. It is formed in a nuclear reactor from uranium-238. The half life of most isotopes of plutonium is pretty short, hence it can’t be found naturally in any meaningful quantity as it decays to other elements rapidly. That doesn’t mean it can’t be made naturally, only that when it is it decays so quick you can’t find much of it left! Uranium has a long half life (the primary isotope, U238, has a half life of about 4.5 billion years!) hence significant amounts of U238 created at the formation of the Earth (around 4.7 billion years ago) could still be around today. P16.3 Planets, satellites, and orbits AQA GCSE Physics P16 Space Kerboodle Answers: Page No. 237 1 i The direction of the force of gravity on the satellite is towards the centre of the earth. ii The direction of its acceleration is towards the centre of the circle because the resultant force on it acts towards the centre of the circle. The acceleration is its change of velocity per second, and its change of velocity is directed towards the centre. b Its velocity continually changes even though its speed is constant. The speed of a satellite in a circular orbit does not change, even though its velocity changes its direction. This is because the force on it is at right angles to its direction of motion. So no work is done by the force on the planet. So the kinetic energy and the speed of the planet do not change. into orbit. 2 a Communications satellites are usually in an orbit at about 36 000 km above the equator with a period of 24 hours. They orbit the Earth in the same direction as the Earth’s spin. So they stay above the same place on the Earth’s surface as they go around the Earth, These kinds of orbits are described as geostationary. b Monitoring satellites are fitted with TV cameras pointing to the Earth. Their uses include weather forecasting, and monitoring the environment Monitoring satellites are in much lower orbits than geostationary satellites and they orbit the Earth once every two or three hours. 3 ® Light from the Sun takes about 3minutes to reach Mercury about eight minutes to reach Earth, and about 40 minutes to reach Jupiter. Jupiter takes about 11 years to orbit the Sun, whereas Mercury takes about 3 months. Neptune, Uranus and Saturn are very far from sun and the light from the sun takes too minutes to reach these planets. b Mercury, Venus and Earth because they are very close to sun and light from sun takes less minutes to reach these planets. 4 ® Mercury orbits the Sun about 4 times each year. The Earth moves on its orbit at a speed of 30 km/s. The closer a planet is to the sun, the faster it travels along its orbit. So at perihelion a planet is moving faster than at aphelion. At aphelion Mercury orbital speed is 56.6km/s. At aphelion, half a Mercury year later, it has slowed to 38.7km/s. P16.4 The expanding universe AQA GCSE Physics P16 Space Kerboodle Answers : Page No. 239 1 a i a distant galaxy is Receding from the Earth. ii a galaxy that shows a blue-shift in its light is Approaching the Earth. b The Sun is in the Milky Way galaxy. Astronomers think that the Andromeda Galaxy will eventually collide with the Milky Way galaxy. evidence that astronomers have to support this prediction is Andromeda’s tangential or sideways velocity with respect to the Milky Way was found to be much smaller than the speed of approach and therefore it is expected that it will directly collide with the Milky Way in around four billion years. 2 a Universe, Andromeda galaxy, Sun and then Earth. b I Because they show red shift. All the distant galaxies show a red-shift. The further away a distant galaxy is from you, the greater its red-shift is. This statement that makes us conclude that quasars are much further away than nearby galaxies ii Quasars can be as bright as a distant galaxy even though they are much smaller. A quasar consists of a supermassive black hole surrounded by an orbiting accretion disk of gas. As gas in the accretion disk falls toward the black hole, energy is released in the form of electromagnetic radiation. Quasars emit energy across the electromagnetic spectrum and can be observed at radio, infrared, visible, ultraviolet, and X-ray wavelengths. The most powerful quasars have luminosities exceeding 1041 W, thousands of times greater than the luminosity of a large galaxy such as the Milky Way. 3 a a red-shift is the light waves are stretched out if the star or galaxy is moving away from you. The wavelength of the waves is increased. This is called a red-shift because the spectrum of light is shifted towards the red part of the spectrum. b i Y is nearer to Earth ii X is moving away faster. 4 Some of the nearest galaxies to Earth have different red shifts, and some have different blue shifts. The light waves are stretched out if the star or galaxy is moving away from Earth. The wavelength of the waves is increased. This is called a red-shift because the spectrum of light is shifted towards the red part of the spectrum. The light waves are squashed together if the star or galaxy is moving towards Earth. The wavelength of the waves is reduced. This is called a blue-shift because the spectrum of light is shifted towards the blue part of the spectrum. P16.5 The beginning and future of the Universe AQA GCSE Physics P16 Space Kerboodle Answers: Page No. 241 1 a Big Bang theory of the universe says that: - The universe is expanding after exploding suddenly (the Big Bang) from a very small and extremely hot and dense region.
- Space, time, and matter were created in the Big Bang.
b many astronomers did not support the Big Bang theory when it was first proposed because these scientists said that the galaxies are being pushed apart. They thought that this is caused by matter entering the universe through ‘white holes'(the opposite of black holes). c It was in 1965 that scientists first detected microwaves coming from every direction in space. The existence of this cosmic microwave background radiation (CMBR) can be explained only by the Big Bang theory. 2 By putting the events A-D in the correct time sequence:D,C,A,B. 3 a Astronomers think that the expansion of the universe is accelerating. Observations since 1998 of supernova in distant galaxies suggest that the distant galaxies are accelerating away from each other. These observations have been checked and confirmed by other astronomers. So astronomers have concluded that the expansion of the universe is accelerating. b If the density of the universe is more than a particular amount, it will stop expanding and go into reverse. Everything will head for a Big Crunch! 4 a Hubble estimated that the speed of recession of a distant galaxy increases by about 22 km/s for every extra distance of one million light years. A distant galaxy is receding away at a speed of 150 000 km/s. Distance of galaxy in light year = 150000/22 = 6818.18million light years. b The Milky Way galaxy is about 100000 light years across. Ratio of the distance to the galaxy in a to the distance across the Milky Way = 6818180000/100000 = 68181.8. Summary questions AQA GCSE Physics P16 Space Kerboodle Answers Page No. 242 1 a Stages for the development of the Sun in the correct sequence are A, C, B, D, E b i After this present stage the sun will become red giant star then it will breakdown and become snowy dwarf star. ii The star having more mass than sun will become red supergiant star later it breakdown. Then become supernova after explosion. Then it will become black hole. 1c The Earth moves around the Sun in a circular orbit at a constant speed. The velocity of Earth changes because its direction show deviations as it moves round Sun, force of gravity between Sun and Earth acts on Earth and makes it change direction, so it experiences an acceleration towards Sun. 2 a i supernova is a big star that explodes ii Difference between a supernova and a distant star like the Sun at present is that supernova swiftly becomes more brighter subsequently fades and a star similar to Sun has constant brightness. B i a black hole is a gigantic object having high gravity which nothing can escape ii stars and planets are pulled by the force of gravity near a black hole iii a neutron star completely made of neutrons. It is formed at core of supernova when the matter is not enough for black hole formation. 3 ai helium was formed in the early universe. ii helium b i lead, uranium ii two elements given in part i formed by fusion of less heavy elements in a supernova explosion iii Sun is formed from the debris of a supernova because of presence of heavy elements on Earth as they can only be found on supernova. 4 a 3, 4, 1, 2 b i The force that can cause dust and gas particles to attract each other is force of gravity. ii Potential Energy is released and stored as Kinetic Energy when dust and gas clouds pull together when they become denser and their elements move faster and clouds heat up iii The stars in a galaxy revolve about the centre of the galaxy they do not pull each other into a large single massive object at the centre because gravitational force acts towards centre of galaxy plays the role of centripetal force to keep stars revolving and makes them not to get collapsed. 5 a i Wave length increases ii This effect is called a red-shift because wavelength made lengthier by motion of galaxy. iii change of wavelength tells us about the motion of the galaxy as galaxy moving away from us, speed of galaxy can be deduced by calculating the amount of red-shift. b Light from a particular nearby galaxy is found to have undergone a blue-shift because of the motion of the galaxy. It is deduced that galaxy moving towards us. c i Edwin Hubble discovered that the further a distant galaxy is from Earth, the greater the red-shift of the light from it. It tells us that universe is growing ii cosmic microwave background radiation is the evidence that led scientists to accept the Big Bang theory of the universe. 6 a i A ii Galaxy C gives a bigger red-shift than galaxy A. C is further away than A b i universe is expanding and all galaxies are moving further away from each other ii we are not in any special place 7 a X, as it appears smaller than Y if seen from Earth b X produces the larger red-shift than Y Practice questions AQA GCSE Physics P16 Space Kerboodle Answers Page No. 243
01.1 Big Bang 01.2 Observation of distant galaxies shows that the universe is expanding. Evidence for this is the light from the galaxies appears stretched is red shift
02.1 1 light year is the distance that light from an object travels in one Earth year 02.2 Relationship between the recession velocity of a galaxy and the distance from the Earth as the distance increases the recession velocity increases they are directly proportional 02.3 In 1929 Hubble used a large reflective telescope and calculated the Hubble Constant to determine the distance of galaxies from the Earth. In 2013 NASA researchers surveyed more than 125 000 galaxies and claim to have measured the Hubble Constant with an uncertainty of less than 5%. reasons that modern researchers can claim to be more accurate in measuring the Hubble Constant are because of more accurate instruments / modern technology and more galaxies studied 03.1 the Sun was formed from dust and gas (nebula) pulled together by gravitational attraction. Collisions between particles caused the temperature to increase enough for hydrogen nuclei to fuse together; forming helium. The energy released by nuclear fusion processes keeps the core of the Sun hot 03.2 the Sun is a main sequence star and is stable because of the force of gravity acting inwards and trying to collapse the Sun is balanced by the outward force and due to the fusion energy trying to expand the Sun. 03.3 A star many times bigger than the Sun will eventually complete its life cycle and become a black hole. Black hole is an area in Space where the gravitational force is so great that not even light can escape 04.1 •
artificial satellites are man-made whilst moons are natural satellites - artificial satellites and moons orbit a planet
- moons have a much higher mass than artificial satellites
- the further away from Earth the higher the orbital speed
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This page contains the detailed and easy notes for AQA GCSE Physics Space for revision and understanding Space.
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New (9-1) AQA GCSE Physics Paper 2: Complete Revision Summary
SPACE
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4.8 Space
- Solar System
- Star Life Cycle
- Satellites
- Red Shift
SOLAR SYSTEM
Solar system contains:
- a) Sun- It is the star
- b) 8 planets – They orbit around the Sun in their orbits
- c) Dwarf Planets – They orbit around the Sun in their orbits
- d) Comets – balls of ice and dust orbiting in elliptical orders around the sun
- e) Asteroids – They are made up of rock and metal and are smaller than the planets
- f) Meteors – Shooting stars which dust and debris which burns when they enter the Earth.
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FORMATION OF A STAR
Cloud of gas, rock and dust
The cloud condensed and pulled to form concentrate Protostar by the gravitational pull.
The particles collide within the cloud and kinetic energy converted to heat energy which resulted in nuclear fusion releasing massive amount of heat
The fusion releasing heat and light turns a proto star into a star.
The star can attract other rocks and dust and form planets.
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LIFE CYCLE OF A STAR
SATELLITES
A satellites is the object that revolves around the planet.
NATURAL ARTIFICIAL
eg Moon They are required for weather forecasting, . monitoring the environment, . communication and GPS tracking.
Satellites moved in a particular orbit around Earth. The force is the centripetal forces which arise due to force of gravity and is directed at right angles.
In the orbit the satellites speed and kinetic energy do not change as its speed is the same. But velocity changes due to change in direction.
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RED SHIFT
DOPPLER EFFECT
When the source is moving away from the observor, the wavelength of the light increases and it is towards the red region of the spectrum and when the source is moving toward the observor, the wavelength of the light decreases and it moves towards the blue region of the spectrum –
The light coming from the stars and from distant galaxies is red shifted
Further the galaxy, greater the red shift.
UNIVERSE IS EXPANDING
BIG BANG THEORY
The Big Bang theory is the main explanation of how the universe began.
Universe was concentrated into one mass which exploded with a bang and is expanding now as well.
Universe always existed. It will last forever. The denisty of the universe will remain constant
EVIDENCE FOR BIG BANG
Red Shift
Cosmic Microwave Background Radiation
CMBR are the remains of the radiation that comes out from the big bang.
Scientists have discovered CMBR coming from distant galaxies which supports the Big Bang.
KEY TERMS
Solar System – Solar system contains Sun, 8 planets, Dwarf Planets, Comets, Asteroids and Meteors.
Protostar – A protostar is a very young star that is still accumulating mass from its main molecular cloud.
Shooting Star – A shooting star is another name for a meteoroid that burns when it crosses the earth’s atmosphere.
Main Sequence Star – A main sequence star is a star that merges hydrogen into its core/nucleus and has a stable balance of the external pressure of central nuclear fusion and the gravitational forces that push inward.
Red Giant – A red giant star is a dying star in the later stages of stellar evolution.
White Dwarf – White dwarf stars mark the evolutionary end point of mass stars from low to intermediate like our Sun.
Black Dwarf – A black dwarf is all that remains after a white dwarf star burns all its heat, but retains its mass.
Red SuperGiants – A red supergiant is a huge giant star that has consumed its core hydrogen reserve. Helium has accumulated in the nucleus and hydrogen is undergoing nuclear fusion in the outer layers.
Super Nova – A supernova is the explosion of a star, the largest explosion that takes place in space.
Neutron Star – Neutron stars are created when giant stars die in supernovae and their nucleus collapses, and protons and electrons fuse together to form neutrons.
Black Hole – A black hole is a region of space-time that shows a gravitational acceleration so strong that nothing, neither particles, not even electromagnetic radiations like light, can escape from it.
Centripetal Force – A centripetal force is a force that causes a body to follow a curved path.
Red Shift – Redshift is a phenomenon in which an object’s electromagnetic radiation increases in wavelength.
Big Bang Theory – The Big Bang theory is the main explanation of how the universe began.
Cosmic Microwave Background Radiation (CMBR) – The cosmic microwave background (CMB) is believed to be a radiation left over from the Big Bang, or the time the universe began.
Dark Matter – Dark matter is a form of matter that is thought to represent about 85% of matter in the universe and about a quarter of its total energy density.
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I have tried my level best to cover the maximum of your specification. But this is not the alternative to the textbook. You should cover the specification or the textbook thoroughly. This is the quick revision to help you cover the gist of everything. In case you spot any errors then do let us know and we will rectify it.
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Wikimedia Commons
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