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IGCSE Physics: Space physics — Practice Questions & Answers
The Earth, Sun and solar system, orbital speed, stars and their life cycles, galaxies, the light-year, redshift and the Big Bang.
418 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Easy
How long does the Earth take to make one complete rotation on its axis?
24 hours
1 month
365 days
12 hours
Tap an answer to check it.
Why One full rotation of the Earth on its axis takes approximately 24 hours, which gives us one day.
2
Multiple choice · Easy
What causes the cycle of day and night on Earth?
The Earth's rotation on its axis
The Earth's orbit around the Sun
The Moon orbiting the Earth
The Sun rotating on its axis
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Why The Earth's rotation on its own axis brings different parts of the planet into and out of sunlight, producing day and night.
3
Multiple choice · Easy
Approximately how long does the Earth take to complete one orbit around the Sun?
One year (about 365 days)
One day
One month
One week
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Why One orbit of the Earth around the Sun takes about 365 days, defining one year.
4
Multiple choice · Easy
Which body orbits the Earth?
The Moon
The Sun
Mars
Jupiter
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Why The Moon is Earth's natural satellite and orbits the Earth, taking roughly one month per orbit.
5
Multiple choice · Easy
What type of astronomical object is the Sun?
A star
A planet
A moon
A comet
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Why The Sun is a star, a huge ball of hot gas that produces its own light and heat.
6
Multiple choice · Easy
What is a galaxy?
A large collection of stars held together by gravity
A single very large planet
A small group of comets
A type of moon
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Why A galaxy is a large collection of stars held together by gravity; our Sun lies within the Milky Way galaxy.
7
Fill in the blank · Easy
The galaxy that contains our Sun and solar system is called the
Check answer
Answer:
Milky
Why Our solar system is located within the Milky Way galaxy.
8
Fill in the blank · Easy
A natural satellite that orbits a planet, such as the one orbiting Earth, is called a
Check answer
Answer:
moon / Moon
Why The Moon is a natural satellite of the Earth, orbiting the planet under gravity.
9
Multiple choice · Medium
Which list places these objects in order from the smallest to the largest?
Moon, planet, star, galaxy
Galaxy, star, planet, moon
Planet, moon, galaxy, star
Star, galaxy, planet, moon
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Why In increasing size: a moon orbits a planet, a planet orbits a star within a solar system, and many stars make up a galaxy.
10
Multiple choice · Medium
Compared with the orbit of a planet, the orbit of a comet around the Sun is usually
a long, highly elongated ellipse
an almost perfect circle
a straight line
a perfect square
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Why Comets travel on highly elongated (eccentric) elliptical orbits, unlike the nearly circular orbits of planets.
Key terms in Space physics
Space physics: The branch of physics that studies the structure, motion, and evolution of objects beyond Earth, including planets, stars, and the universe as a whole.
Solar System: The Sun together with all the objects gravitationally bound to it, including the eight planets, their moons, dwarf planets, asteroids, and comets.
Sun: The star at the centre of the Solar System whose gravity holds the planets in orbit and whose light and heat supply almost all the energy on Earth.
Earth: The third planet from the Sun, the only known body to support life, which both rotates on its axis and revolves around the Sun.
Planet: A large spherical body that orbits a star, has cleared its orbital path of other objects, and does not produce its own light.
Inner planets: The four rocky planets closest to the Sun, namely Mercury, Venus, Earth, and Mars.
Outer planets: The four large gas-giant planets farther from the Sun, namely Jupiter, Saturn, Uranus, and Neptune.
Mercury: The smallest planet and the one closest to the Sun, with the shortest orbital period of all the planets.
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