World celebrates centenary of confirmation of relativity

World celebrates centenary of confirmation of relativity
A half-tone reproduction of one of the negatives taken with the 4-inch lens at Sobral, where the stars measured are between each set of dash marks. Published in F.W. Dyson, A.S. Eddington, C. Davidson, ‘A determination of the deflection of light by the Sun’s gravitational field, from observations made at the Total Eclipse of May 29, 1919’, Memoirs of the Royal Astronomical Society, vol. 62 (1923). Credit: Royal Astronomical Society

Celebrations are underway across the globe to commemorate 100 years since a UK-led expedition confirmed Einstein's general theory of relativity. The theory fundamentally changed our understanding of physics and astronomy, and underpins critical modern technologies such as the satellite-based Global Positioning System (GPS). A series of public events in the UK and around the world will mark this seminal anniversary.

The theory of relativity is essential for the correct operation of GPS systems, which in turn are relied on in many common applications including vehicle satellite navigation (SatNav) systems, weather forecasting, and disaster relief and emergency services. However the world had to wait decades before the applications of such a blue skies result could be realised.

On 29 May 1919, astronomer Sir Arthur Eddington verified Einstein's general theory of relativity by observing the apparent deflection of stars from their normal positions during a . This happens because, according to Einstein's theory, the path of light is bent by gravity when it travels close to a massive object like our Sun.

This effect is measurable during a solar eclipse, when the Sun's light is blocked by the Moon. At such times, the light from the background stars closest to the edge of the Sun is bent, and so these stars appear to be in slightly different positions compared to when they are observed at other times.

The result was based on measurements taken by two UK-led expeditions, one to the island of Principe off the west coast of Africa, and the other to Sobral in Brazil. Two sites were chosen to increase the chances of success, and to ensure good conditions for viewing the eclipse.

World celebrates centenary of confirmation of relativity
Photograph of the lantern slide showing the eclipse of the Sun, Sobral, 29 May 1919, 28 seconds. Reference: RAS No. 291. Credit: Royal Astronomical Society

The expeditions were jointly funded by the Royal Astronomical Society (RAS), the Royal Society, and the Royal Irish Academy, and organised by the Royal Observatory Greenwich. When the results were announced at a joint meeting of the RAS and Royal Society in November of the same year, it made Einstein world famous within days.

In the UK this bank holiday weekend, the Observatory Science Centre in Herstmonceux, Sussex, will be celebrating with a week of family friendly activities and talks from 25 May to 2 June, including a live video-link with Principe, one of the eclipse expedition sites.

At Burlington House in London, on 29 and 31 May, the Royal Astronomical Society will host solar observing events (weather permitting), and the library will display historical images and documents related to the 1919 eclipse. Visitors will also encounter actors playing the roles of Arthur Eddington and Albert Einstein.

Other celebratory activities will be taking place in the UK, Portugal, Principe, Sobral and around the world: more information on all of the events can be found on the Eclipse 1919 events page [ eclipse1919.org/index.php/events ].

World celebrates centenary of confirmation of relativity
Positive copy of the photograph of the solar eclipse by Arthur Eddington and Edwin Cottingham, Principe, 29 May 1919, 2h 17m 33s. Reference: A7/40. Credit: Royal Astronomical Society

Prof. Mike Cruise, President of the Royal Astronomical Society, said, "A century ago astronomers confirmed the —in the process transforming our understanding of the universe forever. The work of Einstein and Eddington is an amazing example of international collaboration in the aftermath of the first world war, and a visible demonstration of how science can overcome barriers in these turbulent times."

In November the RAS and Royal Society will host a conference and public event marking the 100th anniversary of the announcement of the results. The commemoration forms part of the centenary of the International Astronomical Union, founded in 1919, with more than 200 schools around the world signed up to explore the role of gravity in astronomy.


Explore further

New book traces expeditions to test Einstein's theory of relativity

More information: More information on the expeditions, science, and global events can be found on the Eclipse 1919 website at eclipse1919.org/
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May 24, 2019
Zero mention of the guy who followed Eddington, Sir Frank Dyson,
who led the Sobral expedition, the data points of which clustered far
closer to the GR predix than Eddington's scattered set.

May 25, 2019
It is so much more impressive now that the observations of black hole mergers and the shadow of a super massive black hole has enabled astrophysicists to extend and check relativity as low energy perturbative all the way to the stretched event horizon (i.e. just outside the Hawking radiation emission volume).

@JIMBO: Yes, they forgot all the other members of the expedition.

Though IIRC Wikipedia on the subject, the bad observation and unfortunate travel conditions of Eddington's sub-party still tested relativity when they could check the plates back in England. So win-win (except for those who are forgotten in these simplifying celebration setups).

May 25, 2019
If Einstein's theory is true, then why do we believe in the big bang theory?

After all, special relativity says that the time to peak luminosity of type Ia supernova as well as the periodicity of all Cepheid Variables should be observed to be a multiple of their red shift (1+z).

Clearly something else besides expansion is going on with the redshift. Or else, Einstein is wrong.

May 25, 2019
If Einstein's theory is true, then why do we believe in the big bang theory?

After all, special relativity says that the time to peak luminosity of type Ia supernova as well as the periodicity of all Cepheid Variables should be observed to be a multiple of their red shift (1+z).

Clearly something else besides expansion is going on with the redshift. Or else, Einstein is wrong.


Time Dilation in Type Ia Supernova Spectra at High Redshift
Blondin, S. et al.
https://arxiv.org...804.3595

These measurements thus confirm the expansion hypothesis, while unambiguously excluding models that predict no time dilation, such as Zwicky's "tired light" hypothesis. We also test for power-law dependencies of the aging rate on redshift. The best-fit exponent for these models is consistent with the expected 1/(1+z) factor.


May 28, 2019
A friendly warning about some spoil of this 100 yr celebration has four legs: 1) Eddington 'GR proof' of bending light near SUN is true in the unified relativity and QM theory of Dynamic Universe (DU) even after correcting a minor GR based term, 2) The serious flaw of GR equivalence principle and eternally constant c postulate is a fatal kill of GR in terms of Mercury perihelion advance - Mercury is still there after 4.6 B yr birth of Solar system but according to corrected GR based derivation its orbital radius increase per period is continuous and would have casted Mercury out of Solar system long time ago, 3) Eddington's explanation of Gravitational Waves 'Faster than thought' may still be the only valid (vs. 2017 Nobel awarded) 'proof of GW' in the light of DU, 4) DU explanation of 1998 SN1a data without any need of DE/DM has repeatedly explained the flaws of GR/QM in time and distance concepts of Planck dilution and other flaws as function of factor 1/(1+z)^2, see DU books.

May 28, 2019
" The theory fundamentally changed our understanding of physics and astronomy, and underpins critical modern technologies such as the satellite-based Global Positioning System (GPS). A series of public events in the UK and around the world will mark this seminal anniversary. "

This seminal anniversary is a repeat of the epicycle mistake of Earth vs Sun centered world view some 400-500 yrs ago as proven by the GPS foundations of physical vs. mistaken GR thought experimental clocks, see Suntola DU books and seminar papers of www.lfs.fi such as Talvio's 2006 paper of atomic clocks available only since 1970's. The apparent epicycle of eternally constant c is caused by the slowing of ticking rate of physical atomic clock at the same rate as the TRUE value of local c is decelerating in expanding 4-sphere due to the energy balance principle of DU.

May 30, 2019
Actually GPS is the most reliable experimental evidence to disprove special relativity which claims that simultaneity is relative i.e. clocks can never be synchronized relative to more than one inertial reference frame no matter how you correct them, while the fact is that the atomic clocks on the GPS satellites, after corrections, are synchronized relative not only to the ground clocks but also to each other (see Wikipedia on GPS) i.e. they are synchronized relative to all reference frames to show the same absolute time.

Jun 01, 2019
" the atomic clocks on the GPS satellites, after corrections, are synchronized relative not only to the ground clocks but also to each other"

@xinhangshen, good explanation about modern physical atomic clocks of GPS synchronization. Less well-known for the GR based GPS community is the advanced analytical solution by a pioneer of computational mathematics, photogrammetry and geodesy since 1950's by Duane C. Brown. He applied Bundle Adjustment (BA) principle of analytical photogrammetry to SAGA (Short Arch Geodetic Adjustment) program. SAGA used the banded-border sparse solution technique of BA in a nested fashion of DU energy frames - as needed in the advanced photogrammetric and range (cosmic time) sensing system for 4/5-D mapping of the dynamic shape of universe. This requires the expansion of Independent Model (IM) parallax adjustment technique of Gaia mission into the self-calibrating BA mode in network adjustment of range based tracking and other geodetic data.

Jun 04, 2019
I read again Dr Xinhang Shen papers referenced in the discussion part 28Nov2018 issues of Nature. Cosmology, astro-physics and other SR/GR/QM users keep ignoring the physics foundations of some pioneering practical proofs of SAGA from 1960's, Suntola's series of books, published papers and seminars to e.g. explain GPS and SN1a dat. I have referenced them in blogs of popular web site like PO since my 2013 JOGS paper where the apparently constant speed c of light to telescopes and satellite mapping cameras also appears as infinite. The adjusted values for observables of Gauss-Markov model are always unbiased in general Theory of estimation (TOE) as detailed in connection of my early work since 1970's. PO is making progress in understanding Dr Shen and my comments as he got only -2 votes and am getting my best score of 0 since I started annoying some PO regulars (who probably pushed the 'ignore' button). Thank you Dr Shen for speaking up!

Jun 06, 2019
One important point of Brown's SAGA pre-GPS adjustment program is the serial correlation problem of weighted least squares estimation. This problem re-appears also in today's observations of astro-physics such as the system foundations of 'cosmic GPS', SN1a and GW data. The first hurdle to get from Einstein SR/GR/QM period to the surveying industry of mapping is the computational step of inverting the large normal equation matrix N'=A*A of a full-rank design matrix A of least squares A X=L+V using some sparse solution techniques. The range observations of serial correlation need to form N'=A* W A where W is the inverse of non-sparse full weight matrix, caused e.g. by the per-cursor and echo correlations of GW data. SAGA solved this computational problem thereby making l.s. error propagation (inverse of N') more realistic. This is needed in global network adjustment where you also have to adjust the tracking and dynamic self-calibration data of cosmic sensors (Gaia, JWT, etc).

Jul 15, 2019
It's an exceedingly ungrateful task to propose a paradigm change... but somebody has to do it...

see http://www.protsv...tola.pdf

I have done my part to explain the DU paradigm change of physics foundations, cosmology and new mapping technologies of the dynamic 4/5-D model of DU in terms of the advanced math concepts of unified matrix and tensor calculus of extended Gaussian estimation theory of math statistics and inverse problems. Thank you PO for providing this modern forum to start grass-roots understanding of these new concepts in modern world view. Somebody, please take it over I am done, thank you!

Jul 24, 2019
Notice on p 20 of the above Suntola.pdf 5/2019 presentation at lfs.fi Helsinki seminar that the GR/SR introduction of time dilation and length contraction mistakes are caused by comparing two extreme special cases of some DU special cases (GR/SR vs Newtonian 2nd law of motion) not obeyed by modern physical atomic clocks used in GPS and in future navigation systems of exploring the Milky Way neighborhood. The GR based theories and explanations of observables like SN1a and GW (not to speak about BB) are pure speculations in light of this sober finding.

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