 On
December 24, 1968, NASA astronauts Frank Borman, Jim Lovell, and William
Anders became the first humans to orbit the moon. After a successful
launch and trans-lunar injection, the crew of Apollo 8 passed through
the Van Allen radiation belts and entered the mission's cruise phase.
At nearly 69 hours into the flight, the spacecraft went behind the moon
and out of radio contact with mission control. For four long minutes,
the service propulsion system (SPS) engine burned, finally placing the
crew of Apollo 8 in a 193.3 mi (311.1 km) by 69.5 mi (111.9 km) orbit
around the moon. If the burn had lasted too long, the spacecraft could
have crashed upon the surface of the moon. If the burn had ended too
soon, Apollo 8 could have entered a highly elliptical orbit, or been
flung off into space.
After emerging on the sunlight side of the moon, the astronauts began
their scheduled reconnaissance activities, photographing the lunar
surface and identifying potential sites for future landings. Ultimately,
the crew would take over 700 photographs of the moon and over 150
pictures of the Earth. As Apollo 8 rounded the moon for the ninth time,
each astronaut took turns reading from the Book of Genesis and wishing
the world a Merry Christmas. |
2001: A SPACE ODYSSEY © 1968 Turner
Entertainment Co. Released in 1968, "2001:
A Space Odyssey" is a science fiction film
directed by Stanley Kubrick, written by Kubrick and
Arthur C. Clarke. The film deals with thematic elements
of human evolution, technology, artificial intelligence,
and extraterrestrial life, and is notable for its
scientific realism, pioneering special effects, and
provocatively ambiguous and often surreal imagery, sound
in place of traditional narrative techniques and a very
minimal use of dialogue.
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Neutral Theory of Molecular
Evolution
Neutral theory of molecular evolution was first presented by Motoo
Kimura in 1968. Using data on the variation among hemoglobins and
cytochromes-c in a wide range of species, he calculated the evolutionary
rates of these proteins. After extrapolating these rates to the entire
genome, he concluded that there simply could not be strong enough
selection pressures to drive such rapid evolution. He therefore decided
that most evolution at the molecular level was the result of random
processes like mutation and drift.
The neutral theory is the foundation of the molecular clock
technique, which evolutionary molecular biologists use to measure how
much time has passed since species diverged from a common ancestor.
Kimura, M. (1968). "Evolutionary rate at the molecular level". Nature
217: 624-626. |
Pulsars Discovered
Pulsars were discovered by accident by Jocelyn Bell and Antony
Hewish. Antony Hewish, a professor at Cambridge, had a
special radio telescope built by Jocelyn Bell to look for twinkling
sources of radio radiation. These sources were indicators of
Quasars. Jocelyn Bell, was also the Ph.D graduate student that
poured over the massive amount of data produce by the radio telescope,
400 feet of chart data for a four day complete scan of the sky.
For the first time in the history of radio astronomy, a large area of
the sky had been repeatedly surveyed with an extremely sensitive radio
telescope tuned to meter wavelengths. She noticed some unexplained
very regular data that she called "scruff," meaningless and probably
caused by local interference. But the readings showed a very rapid and
regular beat. Bell knew that rapid pulses indicated something small,
while regular pulses indicated something large, so she had trouble
understanding how a beat could be both rapid and regular. How could
something be both small and large at the same time?
Bell and her fellow researchers jokingly referred to the unconfirmed
source of the pulses as LGM, for "Little Green Men," a British
expression for space aliens. After confirming that the telescope was
operating correctly and eliminating man-made objects, such as orbiting
satellites, or local interference, for example from transistor radios,
as the source, Bell and her faculty supervisor, Anthony Hewish,
determined the pulses were coming from a previously unidentified kind of
star. They named it a "pulsar," short for "pulsating star." The
explanation for the radio pulses proved the existence of neutron stars,
incredibly dense remains of massive collapsed stars.
Hewish, Antony; S J Bell, J D H Pilkington, P F Scott, R A Collins
(24 Feb 1968). "Observation of a Rapidly Pulsating Radio Source". Nature
217: 709-713 |