By Lymi

The Solar System

Name 20 worlds and features of the Solar System from NASA images, with a memorable fact about each.

Science20 cards

Add to LymiTry a few cards

Lymi is a flashcard app: it brings each card back right before you’d forget it. Free to use.

  • The Sun and planets

    A glowing orange disc on black, with a cluster of dark spots below the centre.

    Sun

  • The Sun and planets

    A grey, cratered world, half lit by sunlight against black space.

    Mercury

  • Moons

    A dark globe peppered with countless bright crater spots.

    Callisto

  • Moons

    The edge of a hazy orange world with a thin blue layer of haze above it.

    Titan

  • Famous features

    A close view of swirling orange and white clouds around a large reddish oval.

    Great Red Spot

What’s inside

See all 20 cards

Every section is open, so any card can come up in review.

  1. Section 1: The Sun and planets

    9 cards

  2. Section 2: Moons

    8 cards

  3. Section 3: Famous features

    3 cards
Add to Lymi

All 20 cards

In the order you learn them, one section at a time.

1The Sun and planets9 cards

SunA glowing orange disc on black, with a cluster of dark spots below the centre.
A 4.5-billion-year-old star at the centre of the Solar System. It holds 99.8% of the Solar System's mass.
MercuryA grey, cratered world, half lit by sunlight against black space.
The smallest planet and the closest to the Sun. It circles the Sun every 88 days, faster than any other planet.
VenusA pale cream globe wrapped in smooth, featureless clouds.
The hottest planet, at about 467 °C, because its thick atmosphere traps heat. It spins backwards compared with Earth.
EarthA blue globe with white swirling clouds and brown land around a large desert region.
The only planet known to have life and liquid water on its surface. Ocean covers about 71% of it.
MarsA rusty orange globe with dark markings, a long canyon across its middle and a white polar cap.
Iron minerals in its dust rust, which makes it look red. It has two small moons, Phobos and Deimos.
JupiterA large globe striped with cream, tan and brown cloud bands and a reddish oval.
The largest planet, with more than twice the mass of all the other planets combined. A day there lasts about 10 hours.
SaturnA pale yellow globe circled by wide, flat bands that cast a shadow on it.
The second-largest planet, and the only one whose average density is lower than water's.
UranusA smooth, featureless pale blue-green globe on black.
It spins on its side, tilted about 98°, and rolls around the Sun like a ball. Like Venus, it rotates backwards.
NeptuneA deep blue globe with a dark oval storm and thin white clouds.
The most distant planet. Its winds reach more than 1,900 km/h, and one orbit of the Sun takes about 165 years.

2Moons8 cards

MoonA grey globe with dark lava plains and bright craters, one with long bright rays.
Earth's natural satellite. It spins once per orbit, so the same side always faces Earth.
IoA yellow and orange globe blotched with dark spots and pale patches.
A moon of Jupiter and the most volcanically active world in the Solar System, with hundreds of volcanoes.
EuropaA half-lit icy globe criss-crossed by long reddish-brown cracks.
A moon of Jupiter with a salty ocean under its ice shell, holding about twice as much water as Earth's oceans.
GanymedeA brownish globe with dark and pale grooved regions and a bright frosty pole.
Jupiter's moon and the largest moon in the Solar System, bigger than Mercury. It is the only moon with its own magnetic field.
CallistoA dark globe peppered with countless bright crater spots.
Jupiter's second-largest moon and the most heavily cratered object in the Solar System.
TitanThe edge of a hazy orange world with a thin blue layer of haze above it.
Saturn's largest moon and the only moon with a thick atmosphere. It has lakes and seas of liquid methane and ethane.
EnceladusA small, bright white icy moon with craters and smooth, cracked regions.
A small moon of Saturn with the whitest, most reflective surface in the Solar System. Jets of water ice spray from its south pole.
TritonA pale pinkish icy moon with a bright polar cap and a wrinkled, darker band.
Neptune's largest moon and the only large moon that orbits backwards. It is one of the coldest places known, about −235 °C.

3Famous features3 cards

Olympus MonsA view from orbit of a huge, broad mountain with a crater cluster at its summit and a steep cliff around its edge.
A volcano on Mars and the largest volcano in the Solar System. Its base is over 600 km across, about the size of Arizona.
Great Red SpotA close view of swirling orange and white clouds around a large reddish oval.
A giant storm on Jupiter, wider than Earth, that astronomers have watched for well over a century.
Saturn's ringsMany thin, curved bands in enhanced colours, from orange to blue, against black space.
Billions of chunks of ice and rock. They stretch up to 282,000 km from Saturn but are usually only about 10 metres thick.

How it works

  1. Add the deck

    Sign in with Google and it joins your Library, free.

  2. Recall, then turn it over

    Name what the picture shows before you look. Try it on the cards here: they’re from all over the deck.

  3. Review a few minutes a day

    Choose how many cards a day. Lymi brings each one back right before you’d forget it.

The Sun and planets

A pale cream globe wrapped in smooth, featureless clouds.

More like this

Published September 27, 2026