The Week In Numbers: Saturn’s Moon Hides An Ocean, New Human Body Part Discovered, And More

700 miles: the diameter of Dione, an icy moon of Saturn that may be home to a subterranean ocean—and “astrobiological … Continued

Saturnian moon Dione

Icy Dione in front of Saturn. The horizontal stripes near the bottom of the image are Saturn’s rings. Images taken on Oct. 11, 2005, with blue, green and infrared spectral filters were used to create this color view, which approximates the scene as it would appear to the human eye.

700 miles: the diameter of Dione, an icy moon of Saturn that may be home to a subterranean ocean—and “astrobiological potential”

13 million light-years: the distance from Earth to this perplexing black hole, which appears to have recently gone quiet at the center of the Sculptor galaxy

Sleeping Black Hole

1975: the year Lego added human figures to its toy sets. Since then, the figures have featured increasingly angry facial expressions, according to a new study

Angry Lego

75: the average number of Lego bricks for every person on Earth

95 percent: the portion of people who fail to wash their hands properly after using a public restroom, a new bathroom-spying study has found

Wash your hands with soap, people

70,000 metric tons: the amount of commercial spent fuel stored in U.S. nuclear reactors. A start-up called Transatomic Power says it has designed a reactor that could use this fuel stockpile to power the U.S. for 70 years.

15 microns: the thickness of a newly discovered human body part (can you guess where it is?)

The human eye, now slightly less mysterious

$399: the price of the just-announced PlayStation 4, which will feature streaming gaming, new titles, and no restrictions on on used games

Sony PlayStation 4 Hardware

78 percent: the portion of Iceland’s energy production that comes from volcanoes. (An ambitious experiment aims to use a volcano in Oregon to power the U.S.—but there’s a pesky earthquake problem.)

Obsidian Flow At Newberry Volcano

30,000: the population of Songdo, South Korea, one of the world’s most successful eco-cities. A pneumatic waste-collection system transports garbage by tube instead of by truck, and Songdo’s parking garages come with charging stations for electric cars.

Big Dreams

Songdo in South Korea already has 30,000 residents.

40 percent: the portion of Americans between the ages of 18 and 29 that have at least one tattoo. Ever wonder what makes tattoos permanent?

How tattoos work