Friday, October 23, 2026

Plain #6

The day’s seven targets and the closest answers in our lists, with their real values. Points are before bonuses.

Round 1 · 🔄 Planetary rotation period

How many hours does Venus take for one sidereal rotation, ignoring the direction of spin?

Answer

5,832.43 hours

A sidereal rotation is measured against distant stars. Retrograde signs describe direction, not a negative duration.

NASA JPL Solar System Dynamics · Planetary Physical Parameters

Round 2 · 🔋 Element electron affinity

Name a chemical element closest to 3.6 eV.

Target 3.6 eV

Best answer

Chlorine

3.617 eV · 98 points · Source

Also close

Bromine

3.365 eV · 80 points · Source

Also close

Fluorine

3.339 eV · 78 points · Source

Also close

Iodine

3.059 eV · 58 points · Source

Round 3 · 🪐 Planetary mean radius · Golden Round ×2

Name a planet or dwarf planet closest to 710 km.

Target 710 km

Best answer

Makemake

714 km · 98 points · Source

Also close

Haumea

715 km · 98 points · Source

Also close

Ceres

469.7 km · 26 points · Source

Also close

Pluto

1,188.3 km · 18 points · Source

Round 4 · 🧱 Element density

Using its listed density, how many grams would one cubic centimetre of tungsten weigh?

Answer

19.3 g

One cubic centimetre is a cube measuring 1 cm along each edge. Tungsten's symbol is W.

NIH PubChem · Periodic Table of Elements

Round 5 · 🌳 Country forest area in 2023

Name a country or territory closest to 270 km².

Target 270 km²

Best answer

Seychelles

269.6 km² · 100 points · Source

Also close

Guam

282.7 km² · 86 points · Source

Also close

Saint Vincent and the Grenadines

285.6 km² · 83 points · Source

Also close

Northern Mariana Islands

243.6 km² · 71 points · Source

Round 6 · 🧱 Element density

Name a chemical element closest to 9.8K kg/m³.

Target 9,800 kg/m³

Best answer

Bismuth

9,807 kg/m³ · 100 points · Source

Also close

Lutetium

9,840 kg/m³ · 99 points · Source

Also close

Actinium

10,070 kg/m³ · 91 points · Source

Also close

Molybdenum

10,200 kg/m³ · 88 points · Source

Round 7 · 🌐 Country surface area · Finale

Name a country or territory closest to 540 km².

Target 540 km²

Best answer

Guam

541 km² · 99 points · Source

Also close

Isle of Man

572 km² · 83 points · Source

Also close

Saint Lucia

616 km² · 65 points · Source

Also close

Andorra

468 km² · 62 points · Source

All puzzles Play today’s Plain