IGCSE Physics Space physics topical questions

Match each observation to its cause.

1. (a)The Sun appears to rise and set each day.[1]
2. (b)Summer follows spring every year.[1]
3. (c)The Moon’s shape seems to change through the month.[1]

Name each member of the Solar System described.

1. (a)The only star in the Solar System.[1]
2. (b)A ring of minor planets located between Mars and Jupiter.[1]
3. (c)A small body of ice and dust that grows a tail as it nears the Sun.[1]

The Sun contains most of the mass of the Solar System.

1. (a)Name the force that keeps the planets in orbit around the Sun.[1]
2. (b)State what happens to the strength of the Sun’s gravitational field as distance from the Sun increases.[1]
3. (c)State what happens to the orbital speeds of planets further from the Sun.[1]

One evening the Moon appears as a thin crescent; about two weeks later it appears full.

1. (a)Explain why we see phases of the Moon.[2]
2. (b)A solar eclipse can only happen at new Moon. Explain why.[1]
3. (c)Explain why solar eclipses do not happen every month.[1]

The Moon orbits the Earth with an average orbital radius of 3.8 × 10⁸ m and a period of 27 days.

1. (a)Convert the period into seconds.[1]
2. (b)Calculate the Moon’s average orbital speed.[3]
3. (c)State one assumption made in using v = 2πr/T here.[1]

The accretion model describes the formation of the Solar System.

1. (a)State what force pulled the original cloud of gas and dust together.[1]
2. (b)Describe what formed as the rotating cloud flattened.[1]
3. (c)Explain why the four inner planets are rocky and small while the outer four are gaseous and large.[3]

Radio signals (travelling at 3.0 × 10⁸ m/s) are sent from Earth to a spacecraft 18 light-minutes away, and the reply is sent immediately.

1. (a)Calculate how long the signal takes to reach the spacecraft.[1]
2. (b)Calculate the full delay between sending a question and receiving the reply.[2]
3. (c)Explain why mission controllers cannot hold a normal conversation with such a spacecraft.[1]

A planet, Nymphion, orbits its star at an orbital radius of 4.5 × 10¹¹ m with a period of 5.0 years. Take 1 year = 3.2 × 10⁷ s.

1. (a)Convert the orbital period into seconds, in standard form.[1]
2. (b)Calculate the average orbital speed, to 2 significant figures.[3]
3. (c)A second planet orbits the same star at 9.0 × 10¹¹ m. State and explain how its orbital speed compares.[1]

Astronomers observe a supernova in a distant galaxy.

1. (a)Name the type of star that ends its life as a supernova.[1]
2. (b)State what may remain after the explosion.[2]
3. (c)Name the elements formed in supernova explosions that cannot be made in stable stars.[1]
4. (d)Explain how atoms of those elements came to exist on Earth.[1]

Describe the life cycle of a star with a mass similar to the Sun’s, from interstellar cloud to final remnant.

1. (a)Describe the stages from cloud to stable star.[3]
2. (b)Describe what happens when the star runs out of hydrogen, naming the final remnant.[4]

A distant galaxy’s starlight shows its spectral lines shifted to longer wavelengths; its recession speed is measured as 6.6 × 10⁵ m/s. A supernova observed in the galaxy gives its distance as 3.0 × 10²³ m.

1. (a)Explain what the wavelength shift is called and what it shows.[2]
2. (b)Calculate the Hubble constant from this galaxy’s data.[2]
3. (c)Using d/v = 1/H₀, explain why this equation gives an estimate for the age of the Universe, and what that estimate suggests about where all the matter came from.[2]

A radio telescope detects faint microwaves arriving almost equally strongly from every direction in the sky, day and night.

1. (a)Name this radiation and state where it is thought to originate.[2]
2. (b)Explain why radiation from the early Universe reaches us today as microwaves.[2]
3. (c)Explain why this observation supports the Big Bang Theory rather than a steady, unchanging Universe.[2]