1) What is the Aether? Why scientists in the 19th century believed in the aether? What did
Michelson and Morley hope to achieve with their famous \"failed\" experiment? Describe the
Michelson-Morley experiment and its unexpected consequences.
2) Name at least 3 physicists that, at the beginning of the 20th century, tried to explain the results
of Michelson-Morley experiment. Why did they assume that one arm of the interferometer
contracted? Explain Lorentz\'s interpretation of this problem and why he though that the time is
not an absolute quantity independent of the inertial frame.
Solution
Answer-1:
In the 19th century, luminiferous aether (or ether) was a theorized medium for the propagation of
light (electromagnetic radiation).
At that time most physicists accepted the old idea that all of space is filled with the
\"luminiferous ether\". It was well known that light, and all other electromagnetic waves traveled
very well through a vacuum. Yet other waves, sound, for example, required a material medium,
and a common classroom experiment showed that a ringing bell in a glass vacuum jar could not
be heard, yet it could be clearly seen to be vibrating. By analogy, physicists assumed that light
must also have some material medium, a medium that was present even in the best vacuum we
could produce in a bell-jar.
The Michelson-Morley experiment of 1887 was designed to detect the ether\'s effect on the
speed of light, to find out whether the earth\'s speed relative to the ether could be detected.
Michelson and Morley (mostly Michelson) designed a device that split a beam of light and
bounced it off mirrors so that it moved in different directions and finally hit the same target. The
principle at work was that if two beams traveled the same distance along different paths through
the ether, they should move at different speeds and therefore when they hit the final target screen
those light beams would be slightly out of phase with each other, which would create a
recognizable interference pattern. This device therefore came to be known as the Michelson
interferometer. The result was disappointing, because they found absolutely no evidence of the
relative motion bias they were looking for. No matter which path the beam took, light seemed to
be moving at precisely the same speed.
Answer-2:
3 physicists who, at the beginning of the 20th century, tried to explain the results of Michelson-
Morley experiment are: George FitzGerald, Joseph Larmor, and Hendrik Lorentz..
1) What is the Aether Why scientists in the 19th century believed i.pdf
1. 1) What is the Aether? Why scientists in the 19th century believed in the aether? What did
Michelson and Morley hope to achieve with their famous "failed" experiment? Describe the
Michelson-Morley experiment and its unexpected consequences.
2) Name at least 3 physicists that, at the beginning of the 20th century, tried to explain the results
of Michelson-Morley experiment. Why did they assume that one arm of the interferometer
contracted? Explain Lorentz's interpretation of this problem and why he though that the time is
not an absolute quantity independent of the inertial frame.
Solution
Answer-1:
In the 19th century, luminiferous aether (or ether) was a theorized medium for the propagation of
light (electromagnetic radiation).
At that time most physicists accepted the old idea that all of space is filled with the
"luminiferous ether". It was well known that light, and all other electromagnetic waves traveled
very well through a vacuum. Yet other waves, sound, for example, required a material medium,
and a common classroom experiment showed that a ringing bell in a glass vacuum jar could not
be heard, yet it could be clearly seen to be vibrating. By analogy, physicists assumed that light
must also have some material medium, a medium that was present even in the best vacuum we
could produce in a bell-jar.
The Michelson-Morley experiment of 1887 was designed to detect the ether's effect on the
speed of light, to find out whether the earth's speed relative to the ether could be detected.
Michelson and Morley (mostly Michelson) designed a device that split a beam of light and
bounced it off mirrors so that it moved in different directions and finally hit the same target. The
principle at work was that if two beams traveled the same distance along different paths through
the ether, they should move at different speeds and therefore when they hit the final target screen
those light beams would be slightly out of phase with each other, which would create a
recognizable interference pattern. This device therefore came to be known as the Michelson
interferometer. The result was disappointing, because they found absolutely no evidence of the
relative motion bias they were looking for. No matter which path the beam took, light seemed to
be moving at precisely the same speed.
Answer-2:
3 physicists who, at the beginning of the 20th century, tried to explain the results of Michelson-
Morley experiment are: George FitzGerald, Joseph Larmor, and Hendrik Lorentz.
