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السؤال
ماهي نظرية انشتاين
9‏/8‏/2010 تم النشر بواسطة بدون اسم.
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ورقة أينشتاين العلمية الثالثة كانت عن "النظرية النسبية الخاصة"، فتناولت الورقة الزمان، والمكان، والكتلة، والطاقة، وأسهمت نظرية أينشتاين بإزالة الغموض الذي نجم عن التجربة الشهيرة التي أجراها الأمريكيان الفيزيائي "ألبرت ميكلسون والكيميائي إدوارد مورلي" أواخر القرن التاسع عشر في عام 1887، فقد أثبت أينشتاين أن موجات الضوء تستطيع أن تنتشر في الخلاء دون الحاجة لوجود وسط أو مجال، على خلاف الموجات الأخرى المعروفة التي تحتاج إلى وسط تنتشر فيه كالهواء أو الماء وأن سرعة الضوء هي سرعة ثابتة وليست نسبية مع حركة المراقب (الملاحظ)، تجدر الإشارة إلى أن نظرية أينشتاين تلك تناقضت بشكل كلّي مع استنتاجات "إسحاق نيوتن". جاءت تسمية النظرية بالخاصة للتفريق بينها وبين نظرية أينشتاين اللاحقة التي سُمِّيت بالنسبية العامة.
9‏/8‏/2010 تم النشر بواسطة فهد الرحيلي.
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النسبية الخاصة
و النسبية العامة (لم تكتمل )
تفرعة نظرية الكروضوئية من النسبية ولكنها تغتبر دراسة منفصلة حيث نال عنها جائزة نوبل ف الفيزياء والعجيب انة لم ينالها عن النسبية ككل
9‏/8‏/2010 تم النشر بواسطة mu7ammed.
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هذا ما يدحض النسبية

A New Limit on Photon Mass
A new limit on photon mass, less than 10-51 grams or 7 x 10-19 electron volts, has been established by an experiment in which light is aimed at a sensitive torsion balance; if light had mass, the rotating balance would suffer an additional tiny torque. This represents a 20-fold improvement over previous limits on photon mass.
Photon mass is expected to be zero by most physicists, but this is an assumption which must be checked experimentally. A nonzero mass would make trouble for special relativity, Maxwell's equations, and for Coulomb's inverse-square law for electrical attraction.
The work was carried out by Jun Luo and his colleagues at Huazhong University of Science and Technology in Wuhan, China (junluo@mail.hust.edu.cn, 86-27-8755-6653). They have also carried out a measurement of the universal gravitational constant G (Luo et al., Physical Review D, 15 February 1999) and are currently measuring the force of gravity at the sub-millimeter range (a departure from Newton's inverse-square law might suggest the existence of extra spatial dimensions) and are studying the Casimir force, a quantum effect in which nearby parallel plates are drawn together. (Luo et al., Physical Review Letters, 28 February 2003)

Scientists break speed of light
June 4, 2000 NEC Research Institute in Princeton
 Jonathan Leake, Science Editor, Times Newspapers Ltd

SCIENTISTS claim they have broken the ultimate speed barrier:
the speed of light. In research carried out in the United States,
particle physicists have shown that light pulses can be accelerated
to up to 300 times their normal velocity of 186,000 miles per second.
The implications, like the speed, are mind-boggling. On one
interpretation it means that light will arrive at its destination almost
before it has started its journey. In effect, it is leaping forward in
time.
Exact details of the findings remain confidential because they
have been submitted to Nature, the international scientific journal,
for review prior to possible publication.
The work was carried out by Dr Lijun Wang, of the NEC research
institute in Princeton, who transmitted a pulse of light towards a
chamber filled with specially treated caesium gas.
Before the pulse had fully entered the chamber it had gone right
through it and travelled a further 60ft across the laboratory. In
effect it existed in two places at once, a phenomenon that Wang
explains by saying it travelled 300 times faster than light.
The research is already causing controversy among physicists.
What bothers them is that if light could travel forward in time it could
carry information. This would breach one of the basic principles in
physics - causality, which says that a cause must come before an
effect. It would also shatter Einstein's theory of relativity since it
depends in part on the speed of light being unbreachable.
This weekend Wang said he could not give details but confirmed:
"Our light pulses did indeed travel faster than the accepted speed
of light. I hope it will give us a much better understanding of the
nature of light and how it behaves."
Dr Raymond Chiao, professor of physics at the University of
California at Berkeley, who is familiar with Wang's work, said he
was impressedby the findings. "This is a fascinating experiment,"
he said.
In Italy, another group of physicists has also succeeded in
breaking the light speed barrier. In a newly published paper,
physicists at the Italian National Research Council described how
they propagated microwaves at 25% above normal light speed.
The group speculates that it could be possible to transmit
information faster than light.
Dr Guenter Nimtz, of Cologne University, an expert in the field,
agrees. He believes that information can be sent faster than light
and last week gave a paper describing how it could be done to a
conference in Edinburgh. He believes, however, that this will not
breach the principle of causality because the time taken to interpret
the signal would fritter away all the savings.
"The most likely application for this is not in time travel but in
speeding up the way signals move through computer circuits,"
he said.
Wang's experiment is the latest and possibly the most important
evidence that the physical world may not operate according to any
of the accepted conventions.
In the new world that modern science is beginning to perceive,
sub-atomic particles can apparently exist in two places at the
same time - making no distinction between space and time.
Separate experiments carried out by Chiao illustrate this. He
showed that in certain circumstances photons - the particles of
which light is made - could apparently jump between two points
separated by a barrier in what appears to be zero time. The
process, known as tunnelling, has been used to make some of
the most sensitive electron microscopes.
The implications of Wang's experiments will arouse fierce
debate. Many will question whether his work can be interpreted
as proving that light can exceed its normal speed - suggesting
that another mechanism may be at work.
Neil Turok, professor of mathematical physics at Cambridge
University, said he awaited the details with interest, but added:
"I doubt this will change our view of the fundamental laws of
physics."
Wang emphasises that his experiments are relevant only to
light and may not apply to other physical entities. But scientists
are beginning to accept that man may eventually exploit some of
these characteristics for inter-stellar space travel.
14‏/8‏/2010 تم النشر بواسطة arab scientist.
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