Today In Science History – October 26 – Far Side Of The Moon

Luna 3 Moon Photograph

First image of the far side of the Moon. Taken by Soviet Luna 3 spacecraft.
Credit: NASA

On October 26, 1959, people got the first look at the far side of the Moon.

The “far side of the Moon” is a reference to the fact from Earth, you can only see about 59% of the Moon’s surface. This is due to the Moon’s rotational speed is matched to its orbital speed around the Earth. This means the same face of the Moon is always pointed at the Earth. Since the moon’s orbit is elliptical and not a perfect circle, there is a slight difference in the orbital speed as the Moon pulls away or comes closer to Earth. This libration of the moon allows us to occasionally see more than the usual half. This variation allows an extra 9% of the Moon to be seen from Earth. The other 41% would have to wait until 1959.

The Soviet Moon probe Luna 3 was launched October 4, 1959, with the mission to photograph the far side of the Moon. The probe reached the Moon on October 6. On October 7, the Sun was lighting up the far side terrain and Luna 3 began taking pictures. During the next 40 minutes, Luna 3 took 29 pictures, covering 70% of the area we’ve never seen before.

As Luna 3 left the Moon and headed towards the Earth, the Soviets tried to receive the images from the spacecraft, but the signal was too weak. The Soviet scientists were able to pull 17 of the images off before losing contact completely on October 22. On October 26, the Soviets shared the images with the world. The photographs were of low quality but showed a terrain vastly different from the Moon we are used to seeing. The far side was more mountainous and only had two ‘seas’. The new seas were named Mare Moscoviense and Mare Desiderii (Sea of Moscow and Sea of Desire). A later view would find Mare Desiderii was actually a smaller sea (Mare Ingenii – Sea of Ingenuity) and several dark craters.

The Soviets would produce the first Atlas of the far side of the Moon, but the first humans to view the far side directly were the astronauts of Apollo 8 in 1968.

NASA released a far more detailed composite photograph of the Far side using data from the Lunar Reconnaissance Orbiter (LRO) in 2011. Compare this photo to the original Luna 3 image above. See the difference 52 years can make.

Far Side LRO

Far Side of the Moon composite from LRO data.
Credit: NASA/JPL/Arizona State University Click for larger version

Notable Science History Events for October 26

2007 – Arthur Kornberg died.

Arthur Kornberg

Arthur Kornberg (1918 – 2007)
National Institutes of Health

Kornberg was an American biochemist who, with Severo Ochoa was awarded the 1959 Nobel Prize in Medicine for describing how DNA and RNA molecules replicate. He isolated and identified the first DNA polymerase, the enzyme that polymerizes nucleotides into DNA strands during replication.

1989 – Charles John Pedersen died.

Pedersen was an American biochemist who shares the 1987 Nobel Prize in Chemistry with Donald Cram and Jean-Marie Lehn for their research and development of host-guest chemistry. Host-guest chemistry is where two or more molecules/ions bond in unique ways due to their structure in other than covalent bonds. Pedersen’s work was with the chemistry and synthesis of crown ethers or cyclic polyethers.

1972 – Igor Sikorsky died.

Igor Sikorsky 1914

A young Igor Sikorsky (1889 – 1972) in 1914.

Sikorsky was a Russian aeronautical engineering pioneer who developed the first functional helicopter and the first multi-engine airplane. He also designed the Pan-Am Clipper flying boat, the chief ocean crossing airliner of the 1930s.

1959 – Far side of the Moon seen for the first time.

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