Einstein's waves: a 100-year odyssey

"The elegance of Einstein's theory of gravity does not rely on computational power, but rather on the elegance of its princ
"The elegance of Einstein's theory of gravity does not rely on computational power, but rather on the elegance of its principles," said David Cerdeno of Durham University's Institute for Particle Physics Phenomenology

When Albert Einstein forged the bedrock theory of modern physics 100 years ago, he had no computer, no internet, no printer—ballpoint pens and pocket calculators did not exist and few homes had telephones.

Yet it took one of the most sophisticated science tools ever built, at a cost of hundreds of millions of dollars, to prove an idea the scientist had crafted with little more than paper, a fountain pen, hard work and a mind sharper than most.

On Thursday, physicists announced they had detected gravitational waves—hitherto a key unproven element of Einstein's general theory of relativity.

The thesis was published 100 years ago this year, when the world was a very different place, inhabited by a man way ahead of his time.

Radios had been invented, but not yet entered people's homes.

The first transcontinental telephone call was made in 1915, from New York City to San Francisco, as was the first transatlantic call between Arlington, Virginia and Paris, France.

Electric refrigerators were not yet a thing, and motorcars shared the road with horse-drawn carriages.

The Eiffel Tower was the tallest building in the world.

In maths, the height of calculating power was the "comptometer"—a clunky mechanical adding machine that predated the electronic calculator.

Gravitational waves detected
Grapihc explaining what gravitational waves are and how they can be detected

In physics, there were already interferometers, but they bore little resemblance to the Laser Interferometer Gravitational-wave Observatory (LIGO) credited with spotting Einstein's waves.

At the time, rudimentary interferometers were used to search for "aether", a medium theorised, wrongly, to transmit light like air transmits sound.

10 billion times

"The technology that was available at that time was something like 10 billion times less sensitive than what it is today," Cardiff University gravitational physics professor B Sathyaprakash told AFP.

Even if they had been more powerful, it was unlikely anyone would have thought of using them to detect .

"It was only about 50 years after Einstein first proposed (his theory) that we had some understanding of what gravitational waves were," said Sathyaprakash.

"In fact, after working out his initial solution, even Einstein had a hard time believing gravitational waves are real..."

The quest to detect them started in earnest when American physicist Joseph Weber built the first aluminium cylinder-based detectors in the 1960s.

This was followed over subsequent decades by telescopes, satellites, and more recently laser beams—all searching for proof of one man's idea.

Einstein's genius, experts say, was probably unrelated to the time he lived in or the technology at hand.

"The elegance of Einstein's theory of gravity does not rely on computational power, but rather on the elegance of its principles," said David Cerdeno of Durham University's Institute for Particle Physics Phenomenology.

No computer strong enough

Added Sathyaprakash: "Computers are good at crunching numbers, they are not very good at analytical calculations... imagining things in a way that nobody else could do...

"(Einstein) did what are called 'thought experiments'. He was very good at doing it. He would think about a situation, and then try to see what the consequence of that will be if the theory goes in one particular direction... or another."

Just 20 years ago, said Sathyaprakash, there was no computer powerful enough to solve the equations that emerged from Einstein's musings.

A photograph of the physicist's desk, said to have been taken after his death in 1955, presents an image very far removed from shooting laser beams at high-tech physics labs.

The workspace of the man who solved the mysteries of nuclear power, gravity and the speed of light sported no typewriter, no telephone, no radio—no electronic gadget whatsoever.

His desk was covered in books and papers, with a tobacco tin and a pipe, and a large black board against the wall, covered in white chalk equations.

"Not everything can be solved with a computer," said Sathyaprakash.

"He had to do analytical calculations with pencil and paper, and those things took a long time."


Explore further

Gravitational waves: Why the fuss? (Update)

© 2016 AFP

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Feb 12, 2016
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Feb 12, 2016
Anybody can theorize that if a calamitous event on a colossal scale, like an exploding galaxy, or the theoretical collision of two black holes or a collision of two large stars were to occur, that this would result in a massive shock wave, which would be detectable as ripples in space-time. Nothing about that idea is counter-intuitive.

What is counter-intuitive, at least to me, is the reference to gravity waves. Since when is a shock wave a gravity wave? Are those two terms interchangeable? Because if they are, okay, but if they aren't, then stop calling those ripples gravity waves!

It seems to me that if gravity waves were some kind of manifestation of, or property of gravity, then they would be detectable one hundred percent of the time, all the time. The universe is far from static, and the dynamics of bodies in space is such that gravity is forever adapting to changing conditions. Moon's idiosyncratic orbit around Earth should yield detectable gravity waves.

Feb 12, 2016
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Feb 13, 2016
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Feb 13, 2016
By the way we are detecting the Moon's gravity continuously. High and low tide occur twice a day.
Exactly my point. Where are the "gravity waves" to confirm this? Why isn't LIGO detecting them? Are you assuming that I think that gravity doesn't exist?

And by the way, wasn't I on your ignore list, or do you think me just so interesting that you find me a "delight" to your senses?

Feb 15, 2016
"He had to do analytical calculations with pencil and paper, and those things took a long time."

I think this is something that is missing from today's high-pressure environment in science ("publish or perish"). Scientists should be given more time. This is why tenure is so important and the ever decreasing number of tenured positions is worrying.

stop calling those ripples gravity waves

Gravitational waves (a gravity wave is an entirely different critter). And they are not 'shock' waves because a shock wave is a change within a medium. But a gravitational wave is a change OF the medium.

It seems to me that if gravity waves were some kind of manifestation of, or property of gravity, then they would be detectable one hundred percent of the time, all the time.

You have to appreciate how incredibly tiny the amplitudes are and that we are just now, barely, able to detect the most strong of them. Yes, they are all over the place.

Feb 15, 2016
Where are the "gravity waves" to confirm this? Why isn't LIGO detecting them? Are you assuming that I think that gravity doesn't exist?

For example the power of gravitational waves that the Earth-Sun system is emanating is on the order of 200 watts. And this is spread over a HUGE volume. This is still way below the sensitivity of our measuring apparatus.

As more (and more sensitive) detectors come on line we will see many gravitational waves from all over the place.
You're asking for a full telescope with all the whistles and bells when we've just switched on the first pinhole camera. That's not how progress works. You don't jump from 'basic research' to 'fully perfected system' immediately.

Feb 17, 2016
Speed of gravity supposed finite by many scientists since 19th century. So "gravitational waves" (as varying gravity propagated in some direction) were investigated a long time before Einstein. Simple calculation based on Newton`s gravity law can explain new experimental data.

Feb 18, 2016
@Alex
Simple calculation based on Newton`s gravity law can explain new experimental data.

Interesting. Please provide the calculation.


One can make the calculation taking into account gravitational shielding, that should take place espesially for supermassive objects like black holes.
Look at the form of experimental signal from LIGO. And look at the classical model of two rotating mass. Increasing of frequency is due to increasing of angular velocity and energy losses in the radiation of gravity waves at the same time (may be due to continious increasing of masses of the black holes). Increasing of the amplitude is due to increasing of shielding closely before merger. It' s not so simple as gravity law but may give us interesting information about shielding.

Feb 18, 2016
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Feb 19, 2016

There is no such thing, so far.
https://en.wikipe...hielding


Wikipedia is not a scientific reference. Professional researcher is able to provide some calculations himself. In this case it is useful to think about occam's razor and compare the concepts of scielding and distorted space-time.

Feb 19, 2016
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Feb 19, 2016
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Feb 19, 2016

Occam's razor is a double edged sword. It tells me: throw out "gravitational shielding". Good riddance.


You don't understand the meaning of this principal. Schielding is much more simple and natural phenomena that could be directly observed in contrast to fantastic distortion of space-time.

Feb 19, 2016
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Feb 19, 2016
bur we haven't another more complex one.

A man makes its explanation in the edges of its evolution stage. It' s difficult to make a step forward when having any idol.
About gravitational shielding: I found interesting article: http://www.scitec...9eng.pdf

Feb 19, 2016
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Feb 19, 2016
how such a hypothesis is supposed to be tested?

Now it's only a hypothesis (theoretical model).
Gravity waves are much more simple. When neutronium will be created at a laboratory they could be simple observable.

Feb 19, 2016
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Feb 19, 2016
OK ..

Mass and weigh are diferent concepts. Full mass of a system can be obtained as a sum masses of its parts.. for example. And take into account theories of multiuniverces.
As example: two rotating supermassive bodies from neutronium can create gravity waves (like black holes). Even without shielding they create variations of gravity field that flow in all directions.

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