Astronomy & Space · Unit 6
The Sun and Stars
What stars are, star types, brightness, colour and distance
The Sun is a completely ordinary star, and realising that is what turned the night sky from a decoration into a population to be studied.
The unit covers the Sun as a star, star types, brightness and magnitude, the relationship between colour and temperature, and how distances to stars are established at all.
This unit breaks down into 21 short steps and 120 questions, starting at difficulty 2 and building to 3. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.
- Steps
- 21
- Questions
- 120
- Difficulty
- 2-3
What this unit covers
- Colour and Temperature
- Kinds of Stars
- Distances to the Stars
- The Sun as a Star
- Brightness and Magnitude
Where this fits
Follows Our Solar System. Leads into The Lives of Stars.
Where people slip
Blue stars are hotter than red ones, which runs against the everyday association of red with hot. Colour tracks surface temperature, and blue is the high end.
How the unit is structured
The Sun and Stars runs as 21 short steps that unlock in order. 15 are practice rounds and 6 are challenge rounds that pull together everything before them. Questions start at difficulty 2 and climb to 3 as you progress.
Challenge rounds
Example questions
30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 120 in the unit altogether.
Brightness and Magnitude
- Fill the blankLevel 2
1. How bright a star looks from Earth is called its ____ magnitude.
- apparentcorrect
- absolute
- colour
- distance
Apparent magnitude measures how bright a star appears to us, not how bright it truly is.
- Multiple choiceLevel 2
2. What does a star's apparent magnitude describe?
- How bright it looks from Earthcorrect
- How hot its surface is
- How old the star is
- How many planets it has
Apparent magnitude is how bright a star looks from Earth, which depends on both its true brightness and its distance.
- Build the sentenceLevel 3
3. Build a true sentence about the magnitude scale.
Answer: Brighter stars have smaller magnitude numbers
On the magnitude scale, brighter stars have smaller magnitude numbers.
- Choose all that applyLevel 3
4. Which of these affect how bright a star looks from Earth? (Select all that apply.)
- How much light the star gives offcorrect
- How far away it iscorrect
- Dust between us and the starcorrect
- The star's alphabetical name
How much light a star gives off, how far away it is, and dust in between all change how bright it looks; its name does not.
- Fact or fibLevel 3
5. A star that looks dim in our sky must always be a small, weak star.
Answer: False
False. A star can look dim simply because it is very far away, even if it is truly very bright.
- Match the pairsLevel 3
6. Match each brightness term to its meaning.
Answer: Apparent magnitude = How bright it looks from Earth; Absolute magnitude = How bright it truly is; Luminosity = Total energy given off
Apparent magnitude is how bright a star looks, absolute magnitude is how bright it truly is, and luminosity is the total energy it gives off.
Colour and Temperature
- Build the sentenceLevel 2
7. Build a true sentence about star colours.
Answer: Blue stars are hotter than red stars
Blue stars are hotter than red stars because colour depends on temperature.
- Choose all that applyLevel 2
8. Which of these statements about star colours are true? (Select all that apply.)
- Blue stars are hotcorrect
- Red stars are coolcorrect
- A star's colour hints at its temperaturecorrect
- Green is a common star colour
A star's colour reveals its temperature: blue is hot, red is cool. Stars do not appear green.
- Fact or fibLevel 2
9. Red stars are hotter than blue stars.
Answer: False
False. It is the other way around: blue stars are the hottest and red stars are the coolest.
- Fill the blankLevel 2
10. Blue stars are ____ than red stars.
- hottercorrect
- cooler
- closer
- smaller
Blue stars have much higher surface temperatures, so they are hotter than red stars.
- Match the pairsLevel 2
11. Match each star to its colour.
Answer: Betelgeuse = Red; Rigel = Blue; The Sun = Yellow
Betelgeuse is a cool red star, Rigel is a hot blue star, and our Sun is yellow.
- Multiple choiceLevel 2
12. A blue star is generally which of these compared with a red star?
- Hotter than a red starcorrect
- Cooler than a red star
- Exactly the same temperature
- Made of ice, not gas
A star's colour shows its temperature: blue stars are hotter, and red stars are cooler.
Distances to the Stars
- Build the sentenceLevel 2
13. Build a true sentence about our nearest neighbour star.
Answer: Proxima Centauri is the nearest star
Proxima Centauri is the nearest star to the Sun, about 4.2 light-years away.
- Fact or fibLevel 2
14. Stars are so far away that we measure their distances in light-years.
Answer: True
True. Distances between stars are huge, so astronomers use light-years instead of kilometres.
- Fill the blankLevel 2
15. A ____ is the distance light travels in one year.
- light-yearcorrect
- light-hour
- light-second
- star-mile
A light-year is a distance of about 9.5 trillion km, used for measuring the space between stars.
- Guess the numberLevel 2
16. About how many light-years away is Proxima Centauri, the nearest star to the Sun?
Answer: 4.2 light-years
Proxima Centauri sits about 4.2 light-years from us, the closest star apart from the Sun.
- Match the pairsLevel 2
17. Match each object to how far away it is.
Answer: The Sun = 8 light-minutes; Proxima Centauri = 4.2 light-years; Sirius = 8.6 light-years
The Sun is 8 light-minutes away, Proxima Centauri about 4.2 light-years, and Sirius about 8.6 light-years.
- Multiple choiceLevel 2
18. Not counting the Sun, what is the closest star to Earth?
- Proxima Centauricorrect
- Sirius
- Betelgeuse
- Vega
Proxima Centauri is the nearest star to the Sun, about 4.2 light-years away.
Kinds of Stars
- Choose all that applyLevel 2
19. Which of these are kinds of stars? (Select all that apply.)
- Red dwarfcorrect
- Supergiantcorrect
- Main-sequence starcorrect
- Kuiper Belt
Red dwarfs, supergiants and main-sequence stars are all types of star; the Kuiper Belt is a region of icy bodies.
- Fill the blankLevel 2
20. The most common kind of star in the galaxy is the red ____.
- dwarfcorrect
- giant
- supergiant
- comet
Red dwarfs are small, cool and very common, making up most of the stars in the Milky Way.
- Match the pairsLevel 2
21. Match each star to its type.
Answer: The Sun = Yellow dwarf; Betelgeuse = Red supergiant; Proxima Centauri = Red dwarf
The Sun is a yellow dwarf, Betelgeuse a red supergiant, and Proxima Centauri a red dwarf.
- Multiple choiceLevel 2
22. Which type of star is the most common in our galaxy?
- Red dwarfscorrect
- Blue supergiants
- Yellow giants
- White dwarfs
Red dwarfs are small, cool, dim stars, and they make up most of the stars in the Milky Way.
- Build the sentenceLevel 3
23. Build a true sentence about the commonest stars.
Answer: Red dwarfs are the most common stars
Red dwarfs are the most common stars in the galaxy.
- Fact or fibLevel 3
24. The Sun is classified as a main-sequence star.
Answer: True
True. The Sun is a main-sequence star, steadily fusing hydrogen into helium in its core.
The Sun as a Star
- Build the sentenceLevel 2
25. Build a true sentence about the Sun.
Answer: The Sun is a star
The Sun is a star, our nearest one, shining with its own light.
- Choose all that applyLevel 2
26. Which of these are true about the Sun? (Select all that apply.)
- It is a starcorrect
- It is mostly hydrogen and heliumcorrect
- It gives Earth light and heatcorrect
- It is a planet
The Sun is a star made mostly of hydrogen and helium, and it gives Earth light and heat.
- Fact or fibLevel 2
27. The Sun is the closest star to Earth.
Answer: True
True. The Sun is our nearest star by far, which is why it looks so big and bright.
- Fill the blankLevel 2
28. The Sun is the ____ star to Earth.
- closestcorrect
- farthest
- coldest
- smallest
The Sun is our closest star, about 8 light-minutes away, so it looks far bigger and brighter than any other.
- Guess the numberLevel 2
29. About how many degrees C is the Sun's visible surface?
Answer: 5500 degrees C
The Sun's surface is roughly 5500 degrees C, while its core is millions of degrees.
- Multiple choiceLevel 2
30. What is the Sun mostly made of?
- Hydrogen and heliumcorrect
- Rock and metal
- Water and ice
- Oxygen and nitrogen
Like most stars, the Sun is mostly hydrogen and helium gas.
Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.
How you practise
This unit mixes 14 different question formats, so you are recalling and applying rather than recognising the same layout every time.
- Build the sentence
- Choose all that apply
- Fact or fib
- Fill the blank
- Guess the number
- Match the pairs
- Multiple choice
- Odd one out
- Picture question
- Put in order
- Sort into groups
- Spell it
- True or false
- Type the answer
Practise The Sun and Stars
120 questions across 21 steps. Start with step one and crawl at your own pace.
Play this unitRead about The Sun and Stars
Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.
- How Do Stars Form?From cold gas clouds to nuclear fusion, here is the full sequence that turns a drifting cloud into a shining star.August 28, 2026 · 6 min read
- What Is a Supernova?How stars explode, the two main types, and why every heavy element in your body came from one.August 28, 2026 · 6 min read
- What Is a Nebula? The Clouds Where Stars Are Born and DieA nebula is a cloud of gas and dust in space. Some are nurseries where stars form, some are the shed layers of dying stars, a few are exploded wreckage.September 14, 2026 · 4 min read
- How the Sun Makes Its Energy: Fusion at the Heart of a StarThe Sun is not burning. Deep in its core, hydrogen nuclei are fused into helium, and the small mass lost in each fusion is what lights the solar system.September 9, 2026 · 5 min read
More units in Astronomy & Space
- The Day and Night SkyThe Sun, Moon, stars, day and night, and constellations
- Our Solar SystemThe Sun, the planets, their order, and dwarf planets
- The Moon, Earth and SeasonsMoon phases, Earth's spin and orbit, seasons and eclipses
- Rockets and AstronautsRockets, astronauts, the Moon landing, satellites and telescopes
- The Planets in DepthEach planet's features, atmospheres, rings and moons
- Moons, Asteroids and CometsMoons, asteroids, comets, meteors and the outer belts
- Gravity and OrbitsGravity, orbits, Kepler's laws, tides and weightlessness
- Telescopes and ObservingHow telescopes work, their types, wavelengths and observatories