Albert Einstein proposed the General Theory of Relativity in 1915. After an experiment during a solar eclipse, scientists confirmed the theory in 1919. This 1934 photograph shows Dr. Einstein (right) visiting the exhibit booth of the Amateur Astronomers Association of Pittsburgh (AAAP) at the annual conference of the American Association for the Advancement of Science in Pittsburgh. To the front-left of Dr. Einstein is Leo J. Scanlon, AAAP Co-Founder (1929), constructor of the world's first all-aluminum, astronomical observatory dome (1930), and one of the first two Buhl Planetarium lecturers (1939).(Sources: AAAP, Scanlon Family Collection; Photo Reproduction: © Copyright David Smith)
By Glenn A. Walsh
Reporting for SpaceWatchtower
One-hundred years ago today, on
Thursday, 1919 November 13, The New York Times reported that
American experimental physicist Robert A. Millikan (who won the 1923
Nobel Prize in physics) questioned the results of a solar eclipse
experiment confirming the General Theory of Relativity, at a
Connecticut conference of the National Academy of Sciences. Just a
week earlier, on Thursday, 1919 November 6, British astronomer Sir
Arthur Eddington had released the results of the eclipse experiment
which confirmed the General Theory of Relativity, proposed just four
years earlier by German theoretical physicist Albert Einstein.
According to The New York Times
article (complete text of short article near the end of this
blog-post), Dr. Millikan believed that a simpler explanation could
explain the solar eclipse experiment results, which would not
necessarily confirm the General Theory of Relativity.
It was at a
joint meeting of the Royal Society of London and the Royal
Astronomical Society, in London on Thursday, 1919 November 6, that
Dr. Eddington publicly presented the results of an experiment
conducted during the Total Solar Eclipse of Thursday, 1919 May 29.
This experiment was conducted to confirm the General Theory of
Relativity, and according to Dr. Eddington the experiment did,
indeed, confirm Dr. Einstein's new theory.
Over the next
few days, following the public presentation of the eclipse experiment
results, the world's major newspapers exclaimed how revolutionary the
new theory was in providing a new explanation of the Universe, which
greatly differs from the explanation given by Sir Isaac Newton
centuries earlier.
The
headline in The Times
of London, on Friday, 1919 November 7, announced:
“Revolution in
Science – New Theory of the Universe – Newtonian Ideas
Overthrown.”
On
Monday, 1919 November 10, The New York Times
headline proclaimed:
“LIGHTS ALL
ASKEW IN THE HEAVENS
Men of Science
More or Less
Agog Over
Results of Eclipse
Observations
EINSTEIN THEORY
TRIUMPHS.”
Dr. Einstein
became an instant celebrity. This was all the more amazing
considering that British scientists had confirmed a German
scientist's theory, just after the end of the First World War between
the two enemy nations, when there were still bitter feelings on both
sides.
On Thursday,
1915 November 25, in the fourth of a weekly series of four lectures,
Dr. Einstein completed his General Theory of Relativity before the
Prussian Academy of Sciences. Ten years earlier, he had proposed the
Special Theory of Relativity.
In his 1905
Special Theory of Relativity, Dr. Einstein described the structure of
what he called, “Space-Time,” fusing together the three
dimensions of space and the one dimension of time. Dr. Einstein used
the Special Theory of Relativity to illustrate the equivalence of
energy and mass, thus creating his famous equation: E=mc2.
Dr.
Einstein's 1915 General Theory of Relativity described gravitation,
as well as matter, space, and time. In this theory, Dr. Einstein
first proposed that space-time is curved near the gravitational field
of a mass. Thus gravity does not exert a force on an object, as
proposed by Sir Isaac Newton; rather the object follows a natural
path along a curved surface of space-time, when the object nears a
mass.
One consequence
of the General Theory of Relativity is light deflection: rays of
light bend, even if just slightly, when passing a gravitational
field. A real-world test of this hypothesis would demonstrate the
validity of the General Theory of Relativity. But, how to test it?
The logical test
seemed to be to observe star-light from distant stars and determine
whether the star-light was deflected when it passed a massive object,
such as a star, planet, our Moon, or our Sun. However, the light
deflection is quite minimal and nearly impossible to measure when the
star-light passes distant stars, planets, or even our own Moon. And,
star-light passing near our Sun could only be observed during a Total
Eclipse of the Sun, due to the very bright sky-glow near the Sun.
The very first
attempt to measure light deflection was going to be conducted during
the Total Solar Eclipse of Friday, 1914 August 21. This attempt was a
disaster, as it was planned to occur in Crimea just 20 days after
Germany had declared war on Russia, during World War I.
Berlin
University astronomy professor Erwin Freundlich and colleagues had
left Berlin on Sunday, 1914 July 19, before the Declaration of War.
They were arrested as German spies, by the Russians. Their
astronomical equipment, considered military surveillance equipment by
the Russians, was confiscated. A few weeks later, the Berlin
University astronomers were freed during a prisoner exchange.
In a way, this
episode was fortunate for Dr. Einstein. His light deflection
calculation (0.85 second of arc) for the 1914 eclipse was in error.
By the time Dr.
Einstein delivered his third General Theory of Relativity lecture, on
Thursday, 1915 November 18, he had corrected the light deflection
calculation. The correct calculation was 1.7 seconds of arc, exactly
twice the original value.
The first
attempt to measure light deflection, after completion of the General
Theory of Relativity, came by British astronomers during the Total
Solar Eclipse of Saturday, 1918 June 8. However, cloud-cover
prevented observations of the stars.
For the Total
Solar Eclipse of Thursday, 1919 May 29, Dr. Eddington observed from
the island of Principe off of the west coast of Africa, while sending
a second observing expedition to Sobral, Brazil. Successful
observations (of stars in the Constellation Taurus the Bull) were
made from both locations. However, due to the minute deflection of
star-light that actually occurred, it took several months to make the
mathematical calculations necessary to confirm the General Theory of
Relativity.
Finally, Dr.
Eddington did publicly announce the results of his solar eclipse
experiment on Thursday, 1919 November 6.
However, not all
scientists (or even newspaper editorial writers) immediately accepted
Dr. Einstein's new theory. In fact, 100 years ago today, on
Thursday, 1919 November 13, The New York Times reported, in a
mini-editorial on the editorial page (page 12), that Dr. Einstein's
theory was questioned by a noted scientist at a New Haven,
Connecticut conference of the National Academy of Sciences.
The following is
the complete text of this short, two-paragraph article, appearing as
the last of four mini-editorials, in the newspaper's regular Topics
of the Times column ---
Sir
Isaac Finds a Defender
As the now
almost famous attack of Dr. EINSTEIN on the Newtonian law of
gravitation has been declared successful by many eminent men of
science, it is not for the common folk to undertake a defense of the
long-revered formula. People, however, who have felt a bit resentful
at being told that they couldn't possibly understand the new theory,
even if it were explained to them ever so kindly and carefully, will
feel a sort of satisfaction on noting that the soundness of the
Einstein deduction has been questioned by R.A. MILLIKAN in a paper
read before the National Academy of Sciences in session at New Haven.
His plausible
suggestion is that the starlight passing the Sun in eclipse was not
deflected by gravitational attraction, but was refracted in the
perfectly familiar way of light when it entered and emerged from the
gases that form the solar atmosphere. That is understandable as well
as plausible, and it is hard not to hope that it is true.
Robert A. Millikan
(Image Sources: Wikipedia.org, By Unknown (Mondadori Publishers) - http://www.gettyimages.co.uk/search/2/image?phrase=Robert%20Andrews%20Millikan%20%20mondadori&family=editorial&sort=best&page=1&excludenudity=false, Public Domain, https://commons.wikimedia.org/w/index.php?curid=41222283)
Robert A. Millikan was an American experimental physicist who was
honored with the 1923 Nobel Prize in physics, for the measurement of
the elementary electric charge and for his work on the photoelectric
effect. He became the first president (official title: Chairman of
the Executive Council) of the California Institute of Technology
(which, today, includes management of the Jet Propulsion Laboratory for NASA)
in 1921, serving in that position until 1945.
Internet Links to Additional Information ---
Albert Einstein:
Link 1 >>> http://www.alberteinsteinsite.com/einsteinbiography.html
Link 2 >>> https://en.wikipedia.org/wiki/Albert_Einstein
Sir Arthur Eddington:
Link 1 >>> https://www.famousscientists.org/arthur-eddington/
Link 2 >>> https://en.wikipedia.org/wiki/Arthur_Eddington
Robert A. Millikan:
Link 1 >>> https://www.nobelprize.org/prizes/physics/1923/millikan/biographical/
Link 2 >>> https://en.wikipedia.org/wiki/Robert_Andrews_Millikan
Total Solar Eclipse of Thursday, 1919 May 29:
Link 1 >>> https://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle1901/SE1919May29Tgoogle.html
Link 2 >>> https://en.wikipedia.org/wiki/Solar_eclipse_of_May_29,_1919
Eddington 1919 Solar Eclipse Experiment:
Link >>> https://en.wikipedia.org/wiki/Eddington_experiment
General Theory of Relativity:
Link 1 >>> https://www.physicsoftheuniverse.com/topics_relativity_general.html
Link 2 >>> https://en.wikipedia.org/wiki/General_relativity
Related Blog-Posts ---
"Book: 'Einstein for Anyone: A Quick Read'." Thur., 2016 Dec. 15.
Link >>> https://spacewatchtower.blogspot.com/2016/12/book-einstein-for-anyone-quick-read.html
"Centennial: Einstein's General Theory of Relativity." Wed., 2015 Nov. 25.
Link >>> https://spacewatchtower.blogspot.com/2015/11/centennial-einsteins-general-theory-of.html
Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
Wednesday, 2019 November 13.
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gaw
Glenn A. Walsh, Informal Science Educator & Communicator:
< http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: < http://buhlplanetarium.tripod.com/fotz/ >
SpaceWatchtower Editor / Author: < http://spacewatchtower.blogspot.com/ >
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetarium.
* Adler Planetarium, Chicago:
< http://adlerplanetarium.
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie.
