Pacific Science Center
Bringing science to life.
PacSci-Doku: “Pluto Puzzle”
By Dennis Schatz – Senior Advisor
Do you Sudoku? It’s one of the hottest number games around! Well, here’s a twist we think you’ll love. We call it PacSci-Doku. Can you guess why? Here’s how it works. Instead of filling in the blanks with numbers, we use letters. Hidden in one of the columns or rows is the answer to a science question. You’ll find information about the answer on the answer tab below.
The question in this edition is:
What unexpected feature was recently identified on Pluto?
To find the answer, complete this PacSci-Doku using the following nine letters:
u A e S s D d N n

The Puzzle
Puzzle Difficulty: Hard
The Answer

The Solution
The question in this edition is:
What unexpected feature was recently identified on Pluto?
The answer: Sand Dunes
Sand dunes usually generate images of the Sahara Desert, the dunes along the Oregon and California coasts, or the deserts of the southwest. Recent analyses of images of Pluto show something very similar, but made of methane frozen out of the atmosphere consisting of methane, nitrogen and carbon monoxide. The grains of methane sand are probably around 1/100th of an inch, so would easily flow through your hands if you could stand the cold. Production of dunes requires not only the sand, but wind. This is not something scientists expected since the gravity of Pluto is 1/16th that of the Earth, and the thickness of its atmosphere is 1/100,000th that of the Earth. However, recent computer modeling of Pluto’s atmosphere shows it could have winds of around 20 miles per hour – strong enough to produce dunes of methane ice. Read more about the methane dunes on Pluto.