Side of the moon you can't see 'is not dark, it's just far'

January 3, 2019 by Seth Borenstein
This composite image made available by NASA in 2011 shows the far side of Earth's moon. The moon is what scientists call "tidally locked" which means the same side always faces us, while another side always faces away, says Harvard astronomer Avi Loeb. "The other side is not dark, it's just far." (NASA/Goddard/Arizona State University via AP)

Despite the name of Pink Floyd's best-selling album, the side of the moon you can't see isn't always dark. But it is far.

So call the area where a Chinese spacecraft just landed the far side, not the .

"The other side sees the sun sometimes. The other side is not dark, it's just far," said Harvard astronomer Avi Loeb. "It's a mistake."

The moon is what scientists call "tidally locked " which means the same side always faces us, while another side always faces away, Loeb said. When Earth views a darkened new moon, the far side is lit. When there's a full moon in our sky, the far side is dark.

Every semester, Purdue University lunar and planetary scientist Jay Melosh demonstrates how the far side gets light using a as the sun and students playing the roles of the moon and the Earth. But students still get it wrong on the midterm, calling it the dark side.

Melosh traces the myth back to a Walt Disney television special in 1955 that talked about it always being dark on the other side of the moon and futuristic astronauts dropping flares.

The term dark side really took off in 1973 with the Pink Floyd's mesmerizing album "The Dark Side of the Moon."

While China is the first to land a spacecraft on the far side, there have been plenty of detailed photographs taken by orbiting spacecraft. The first grainy pictures came from a former Soviet Union craft in 1959. NASA's Apollo 8 astronauts saw it first when they orbited the moon 50 years ago.

Explore further: China lunar probe sheds light on the 'dark' side of the moon

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3 comments

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Solon
not rated yet Jan 04, 2019
Hows about some actual illuminance figures, light and dark are purely subjective.
rgw
not rated yet Jan 06, 2019
"There is no dark side
of the moon really.
Matter of fact
it's all dark."

Pink Floyd, 'Eclipse' 1973
Da Schneib
1 / 5 (1) Jan 06, 2019
Anybody who's stupid enough to think the "dark side of the Moon" isn't illuminated half of the month is brain dead.

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