Size It Up

ALL ANSWERS · SPACE · DAILY No. 13 · SEPTEMBER 16, 2026

Size It Up Space answer: September 16

The five Space silhouettes for September 16, with the true sizes. If you have not played yet, this page is a spoiler — play these five first, then come back to argue with the numbers.

Day 13 ran from Mimas (396.4 km) to Titan (5,150 km). The widest gap was round 3, Tethys against Titan, at 4.8×; the closest call was round 5, Ceres against Oberon, only 1.6× apart — the kind of round that separates a 90 from a 60.

  1. ROUND 1

    Ariel (Uranus’s moon · mean diameter) vs Moon (Earth’s moon · mean diameter)

    Moon · reference · 3,475 km
    Ariel · true diameter · 1,158 km

    3.0× shorter than the Moon

    Ariel, a moon of Uranus, has a mean diameter of about 1,157.8 km. This is the body’s size, not an orbital distance.

  2. ROUND 2

    Rhea (Saturn’s moon · mean diameter) vs Callisto (Jupiter’s moon · mean diameter)

    Callisto · reference · 4,821 km
    Rhea · true diameter · 1,527 km

    3.2× shorter than Callisto

    Rhea, a moon of Saturn, has a mean diameter of about 1,527 km. This is the body’s size, not an orbital distance.

  3. ROUND 3

    Tethys (Saturn’s moon · mean diameter) vs Titan (Saturn’s moon · mean diameter)

    Titan · reference · 5,150 km
    Tethys · true diameter · 1,062 km

    4.8× shorter than Titan

    Tethys, a moon of Saturn, has a mean diameter of about 1,062.2 km. This is the body’s size, not an orbital distance.

  4. ROUND 4

    Mimas (Saturn’s moon · mean diameter) vs Charon (Pluto’s moon · mean diameter)

    Charon · reference · 1,212 km
    Mimas · true diameter · 396.4 km

    3.1× shorter than Charon

    Mimas, a moon of Saturn, has a mean diameter of about 396.4 km. This is the body’s size, not an orbital distance.

  5. ROUND 5

    Ceres (mean diameter) vs Oberon (Uranus’s moon · mean diameter)

    Oberon · reference · 1,523 km
    Ceres · true diameter · 939.4 km

    1.6× shorter than Oberon

    Ceres has a mean diameter of about 939.4 km. This is the body’s size, not an orbital distance.

Beat these tomorrow

Every round is worth up to 100 points: within 6% of the true size scores 100, half or double scores 45, five times off scores zero. The daily puzzle is the same five for everyone and refreshes at midnight in your time zone; if you want more than five, Size It Up Unlimited draws fresh pairs from the whole library for as long as you like.

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MixedAnimals, planets and everyday things. AnimalsLength, height or wingspan — every round names the axis. GeographyEast–west or north–south span, never area. Pop CultureCheck the version. Compare the measured dimension. VehiclesLength end to end, or height for the ones that stand upright. DinosaursCompare estimated body length, from snout to tail tip. SpaceCompare body diameter. Rings and orbital distances are excluded. Everyday ObjectsLength, height or width — every round names the axis. InsectsBody length or wingspan — read the named measurement. LandmarksRead the named height, length or main span — including its endpoints. Food & DrinkRead the selected size and axis — length, diameter or container height.
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