In the late 1500s, Florentine astronomer, physicist, and engineer Galileo Galilei theorized
that mass does not affect gravitational pull, contradicting Aristotle. Galilei
believed that all things fall at the same rate, regardless of how heavy they are.
In the summer of 1971, after more than three and a half centuries and 239,000 miles away from Italy,
NASA astronaut Dave Scott held a 2.9-pound aluminum geological hammer in one hand
and a one-ounce falcon feather 44 times lighter in the other.
Scott and the Apollo 15 team, the fourth mission to land on the Moon, were determined to test
Galileo’s theory and did it before a live television audience from all over the world.
As the astronaut finally dropped both objects,
the almost 400-year-old hypothesis was finally settled.
Drop The Ball
When Florentinian Galileo Galilei was young,
one of his contemporaries described Aristotle's hypothesis of how objects fall as: [QUOTE]
"There is a natural place for everything to seek, as:
Heavy things go downward, Fire upward, And rivers to the sea."
According to the Greek philosopher and polymath, it was in the nature
of falling that heavier objects reached the ground faster than lighter ones.
As Galileo grew up and became a polymath himself,
the gifted 26-year-old became a professor in Math and Engineering at the University of Pisa.
Then, between 1589 and 1592, the Italian scientist started putting together the basis
for a new hypothesis. He firmly believed that if there was no air resistance,
all objects should fall at speed proportional to their density.
To test out this modified Aristotelian theory, he decided to carry out a series of experiments.
Back in the Middle Ages, there was no established scientific method to test out this kind of trial,
and controlled experiments were mostly unknown.
Thus, all the scarce information and reports about these experiments
were recorded by Galileo's pupil Vincenzo Viviani,
who gathered the findings and published them in a biography he wrote about his tutor in 1717.
According to the biography, in order to demonstrate that any object’s time
of descent was independent of its mass, Galileo dropped two spheres of different
sizes from the Leaning Tower of Pisa, but their weight and material are unknown.
Galileo found that the heavier ball hit the ground first. However,
it was only by a fraction of a second, as both objects hit the ground nearly at the same time.
According to his findings, although the lighter ball started its descent faster,
the heavier one quickly caught up.
Still, it is unclear whether Galileo actually performed the experiment or if it was some
fable metaphor, but the Florentinian’s findings were a turning point in the history of science.
Apollo 15
Almost four centuries later, Galileo's theories would be proved once again,
this time on camera. And on the Moon.
Apollo 15 was the ninth crewed expedition in NASA's Apollo program. Although this was
the fourth American mission to land on the Moon, it would also achieve several firsts.
With the most extended stay on the Moon yet,
Apollo 15 would place a greater focus on science than ever before. The mission
would also be the first to use the Lunar Roving Vehicle, a battery-powered four-wheeled rover.
The mission crew members were commander David Scott, who was on his third space mission,
and two first-timers, Command module pilot Alfred Worden and Lunar module pilot James Irwin.
Already having an interest in Geology,
Scott also made plans for his crew to go on field trips with geologist Lee Silver.
On July 26, 1971, Apollo 15 launched from the Kennedy Space Center. The outward flight to the
Moon's orbit experienced only minor difficulties and the crew entered lunar orbit safely.
After landing near the Hadley Rille region on the near side of the Moon,
each crewmember performed different activities between July 30 and August 2.
By using the Lunar Roving Vehicle, the crew was also able to travel further from the lunar
module than had ever been achieved before, as well as collect 170 pounds of surface material.
The Hammer and The Feather
At the end of the last mission's moonwalk, on August 2, 1971,
Commander Scott was readying to perform a live demonstration for the television cameras.
As Scott held out two objects in his hand, he turned to the camera and said: [QUOTE]
"Well, in my left hand, I have a feather; in my right hand, a hammer. And I guess one of
the reasons we got here today was because of a gentleman named Galileo, a long time ago,
who made a rather significant discovery about falling objects in gravity fields.
And we thought where would be a better place to confirm his findings than on the Moon."
After zooming in on the two objects, a geologic hammer and a falcon feather,
Scott pulled back to explain the experiment: [QUOTE] "I'll drop the two of them here and,
hopefully, they'll hit the ground at the same time."
As they were essentially in a vacuum, there was no air resistance and both objects were
supposed to hit the ground at the same time, proving what Galileo had concluded hundreds
of years before about objects falling at the same rate regardless of their mass.
As Scott let go of the objects and simultaneously pulled his hands out of the way,
both the hammer and the feather hit the surface of the Moon at virtually the same time.
Capsule communicator Joseph Allen was on the other side of the line, where Houston was already
clapping in celebration, and both he and Scott exclaimed gleefully: [QUOTE] “How about that!”
The short experiment proved that Galileo was correct in his findings.
According to the mission's transcript,
Scott mentioned that performing the experiment had been Allen's idea
when they all pitched in different suggestions during one night at the crew's quarters.
After deciding to try out Galileo's theory, Scott contacted a friend and
professor at the Air Force Academy who had a falcon as a mascot, to ask for a feather.
After performing the experiment, Scott asserted on
camera that the experience had been one of the great moments of the Apollo program.
Scott
After completing their mission, Apollo 15 splashed down in the Pacific Ocean on August 7.
The crew was the first in NASA's history not to be quarantined upon return,
and they immediately flew to Houston to debrief.
Afterward, the team showed up to the usual circuit of addresses to Congress,
parties, and foreign trips that all Apollo astronauts had to meet.
During a trip to Moscow, Scott met with a team of top Soviet technical experts and cosmonauts,
including Alexei Leonov, with whom he went on
to publish a joint memoir about their experiences in outer space.
Although Apollo 15 accomplished all its set of goals, the mission was marred by negative
publicity when in 1972 it was publicized that the crew carried unapproved postal covers to the Moon,
some of them sold by a West German stamp dealer.
None of the astronauts in that mission ever went to the Moon again.
In the mid-1970s, Scott retired from the Air Force after accepting the
post of deputy director of NASA's Dryden Flight Research Center, and the astronaut
continued to fly aircraft alongside his friend, consulting pilot Chuck Yaeger.
For decades, David Scott also collaborated as a consultant in different space-related projects,
including blockbuster Hollywood films.
A lover of science and history, David Scott is the last remaining survivor of
the Apollo 15 mission and retired from the public eye decades ago,
but his spirit of experimentation and wonder still remains with NASA's younger generation.
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