January 22, 2019 Tuesday
Bedtime Story
Tests for General Relativity
The Modern Tests of general relativity
consist of seven tests four of which I had enumerated last night.
The rest are as follows:
(5) Gravitational redshift – is the first
of the classical tests
(6) Frame-dragging tests – based upon
Lense-Thirring effect (named after two Austrian physicists Josef Lense and Hans
Thirring) or the effect a large rotating mass like earth has on the change in
the orientation of the rotational axis of a gyroscope
(7) Tests of the gravitational potential at
small distances –
C. Strong Field tests – based on the
prediction of the theory that very strong gravitational fields ought to be
present close around the black holes
(1) Binary Pulsars – based on the
prediction that rapidly rotating neutron stars ought to emit gravitational
waves that travel at the speed of the light
(2) Direct Detection of the gravitational
waves – I hope you recall the LIGO bedtime story series that I did in February
2016 when the team first reported detecting the gravitation waves (a truly
monumental feat of experimental physics!)
(3) Gravitational redshift – based on the
redshift of light coming from a star orbiting a supermassive black hole
(4) Strong Equivalence Principle – needs
some explanation but we shall skip for now
(5) x-ray spectroscopy – based on the
prediction of the theory that the trajectories of moving photons is affected by
gravitational fields (which in extreme cases leads to the no-hair theorem that
I can’t go into now)
D. Cosmological tests
(1) Gravitational lensing – based on the
prediction that large galaxies act as a strong gravitational lens for light
coming from any such other galaxy behind it towards Earth thereby creating the
well known Einstein-Chwolson ring (predicted by Russian physicist Orest Danilovich
Khvolson in 1924 and published in the world’s oldest astronomical journal
‘Astronomical Notes’ or in German ‘Astronomische Nachrichten’)
This is a kind of scrutiny that even a
renowned genius of the stature of Einstein is subjected to till date.
It would take just a single test to fail
for astrophysicists to supplant the general relativity with something better
and this is exactly the Bayesian way of thinking that needs to be emphasized to
students in primary education.
Popper saw that even though Newton was
proved right so many times for so many years and the foundations laid upon by
him seemed to be rock solid and yet in one stroke these two men had dethroned
the solidness on Newtonian ideas.
That is the reason why Karl Popper gave
disproportionate emphasis on the principle of falsification to scientific
theories.
What is applicable to physics is also
applicable to medicine.
This is the reason why we shall return back
to the subject of homeopathy and ayurveda.
Stay tuned to the voice of an
average story storytelling chimpanzee or login at http://panarrans.blogspot.com
Good night Mon Ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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