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Tag archives: Einstein

A century ago Einstein sparked the notion of the laser

Another brilliant idea: laser beams illuminate fog (Courtesy: CC BY 2.0/ Jeff Keyzer)

Another brilliant idea: laser beams illuminate fog. (CC BY 2.0/ Jeff Keyzer)

By Philip Ball 

I just got back from having my broken wrist X-rayed (it’s doing fine, thanks), and noticed that a laser beam was used to position and align the X-ray source. Hardly the most sophisticated use of these optical devices, it’s true, but a little reminder that there’s probably hardly a day goes by in the life of an average urbanite without the laser’s beam of coherent photons impinging on it. From supermarket barcode scanning to broadband fibre-optic telecommunications, lasers are everywhere.

The fundamental idea behind this mainstay of modern life was published one hundred years ago by Albert Einstein. But blink and you’ll miss it in his seminal paper, “The quantum theory of radiation”, published in German in Physikalische Zeitschrift 18 121 (English translation here). Einstein is trying to work out what Max Planck’s “quantum hypothesis” – that the energy of an oscillator must take discrete values equal to some integer multiple of the oscillation frequency times a constant h – implies for the way light interacts with matter.

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Happy birthday Curiosity, overpaid footballers, cheeky Einstein photo sells

By Sarah Tesh, Hamish Johnston and Michael Banks

It’s Mars Curiosity’s 5th birthday tomorrow! The NASA rover touched down on 5 August 2012 and has been exploring the red planet ever since. It has travelled more than 10 miles, studied more than 600 vertical feet of rock and even proved that Mars was once habitable. While a Mars birthday party for Curiosity would be a lonely affair, researchers at NASA Goddard Space Flight Center have programmed the rover to sing “Happy birthday” to itself using its Sample Analysis at Mars (SAM) instrument. To introduce ground samples into the rover, SAM resonates through a range of frequencies, so the researchers programmed the instrument to run through the frequencies of the celebratory song.

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Einstein world record, Spider-Man physics, quantum films and cakes

 

By Sarah Tesh and James Dacey

A world-record-breaking hoard of Albert Einsteins invaded Toronto in Canada on Tuesday 28 March. 404 people gathered in the city’s MaRS Discovery District dressed in the genius’s quintessential blazer and tie, and sporting bushy white wigs and fluffy mustaches. As well as breaking the previous Guinness World Record of 99 Einsteins, the gathering kicked off this year’s Next Einstein Competition. The online contest invites the public to submit ideas that can make the world a better place and awards the winner $10,000 to help them realize it.

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Robots at arXiv, physicist runs for US president, Einstein emojis galore

 

Preprint pioneer: Paul Ginsparg in 2002, long before arXiv received 10,000 papers per month (Courtesy: MacArthur Foundation)

Preprint pioneer: Paul Ginsparg in 2002, long before arXiv received 10,000 papers per month. (Courtesy: MacArthur Foundation)

By Hamish Johnston

Last month the arXiv preprint server received more than 10,000 papers – the first time in the history of the physics paper depository. While arXiv papers are not peer reviewed, they are checked to ensure that they are “of interest, relevance and value” to the scientific community – which arXiv promises to do within 24 h of submission. So how do they do it? Surely someone doesn’t read every word of every paper? The answer can be found in “What counts as science?”, which appears in Nautilus. arXiv was set up in 1991 by the physicist Paul Ginsparg, who explains how the service uses machine learning to sort the wheat from the chaff – something that has attracted controversy.

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Earth-gazing, a very noteworthy astronomer, chilling with Einstein and more

The Earth as seen by Himawari-8 earlier today. (Courtesy: JSA)

The Earth as seen by Himawari-8 earlier today. (Courtesy: JSA)

By Hamish Johnston

Who hasn’t wanted to float high above the Earth and gaze down on our planet as sunlight and clouds dapple across its surface. Thanks to the “Glittering Blue” animation, such views are not just for a privileged few astronauts. This stunning animation of one day’s observations from the Japanese weather satellite Himawari-8 has been put together by satellite-imagery analyst Charlie Lloyd. He has also included a nice FAQ page that explains some of the amazing phenomena captured by the satellite, including a huge tropical storm and the daily cloud cycles of a rainforest.

You can read more about Lloyd and the images in The Atlantic article “A New and Stunning Way to See the Whole Earth”. If you want to know what Himawari-8 is seeing right now, it has its own live webcam.

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The life and times of Einstein – ‘A vagabond and a wanderer’

Falling in: Sir Roger's sketch of a black hole collapse, at his talk (Courtesy: Tushna Commissariat)

Falling in: Sir Roger Penrose’s sketch of a black-hole collapse. (Courtesy: Tushna Commissariat)

By Tushna Commissariat

So much has been said about Einstein and his general theory of relativity (GR) that one would assume there isn’t two entire days worth of talks and lectures that could shed new light on both the man and his work. But that is precisely what happened last weekend at Queen Mary University London’s “Einstein’s Legacy: Celebrating 100 years of General Relativity” conference, where a mix of scientists, writers and journalists talked about everything from the “physiology of GR” to light cones and black holes, to M-theory and even GR’s “sociological spin-offs”.

The opening talk, “Not so sudden genius”, was given by journalist and author of “Einstein: A hundred years of relativity“, Andrew Robinson. The talk was very fascinating and early on Robinson outlined that Einstein stood on the shoulders of many scientists and not just “giants” such as Newton and Mach. But he also acknowledged that the scientist was always a bit of a loner and he preferred it this way. Robinson rightly pointed out that until 1907, Einstein was “working in brilliant obscurity” and later, even once fame found him, rootlessness really suited Einstein’s personality – he described himself as “a vagabond and a wanderer”.

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Celebrating the centenary of Einstein’s general theory of relativity and asking what theorists have done lately

 

By Hamish Johnston

This week, people all over the world have been celebrating the 100th anniversary of Einstein’s general theory of relativity (GR). Einstein delivered his theory this week in November 1915. Not surprisingly, the Web has been buzzing with tributes to Einstein and explanations of his theory.

In the above video, the physicist Brian Greene and two young assistants demonstrate Einstein’s explanation of gravity using a huge piece of stretched Spandex. Why they have this Spandex ring in what appears to be their living room remains a mystery, but it and a large number of marbles do the trick when it comes to explaining GR.

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Einstein’s legacy, 100 years on

 

By Tushna Commissariat

As readers of Physics World, you probably don’t need me to tell you that this year marks 100 years since legendary physicist Albert Einstein laid the foundations for his revolutionary general theory of relativity (GR). This month marks the exact time when he began giving a series of four weekly lectures – the first of which was on 4 November 1915 – to the Prussian Academy of Sciences in Berlin. Indeed, today is the centenary of the final lecture, when he presented his “Field equations of gravitation”. In the video above, philosopher and one-time physicist Jürgen Renn, from the Max Planck Institute for the History of Science in Berlin, gives a short and sweet explanation of GR and its impact on physics.

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Physicists in motion: immigration and the Nobel prize

PW-2015-09-30-blog-migration

Around the world: how has immigration shaped the global physics community? (Courtesy: iStockphoto/Joel Carillet)

By Hamish Johnston

In December 1938 Enrico Fermi travelled to Stockholm, where he was presented with that year’s Nobel Prize for Physics for his insights into the atomic nucleus. But after the ceremony, Fermi did not return to his native Italy. Instead, he joined his wife and young children on a voyage to the US. Fermi went on to make major contributions to physics in that country – including playing crucial roles in developing nuclear weapons and nuclear energy.

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The ins and outs of black holes and a new way of thinking about general relativity

 

By Hamish Johnston

While at the Convergence conference at the Perimeter Institute (PI), Physics World’s Louise Mayor and I had dinner with Sean Gryb. He did his PhD at the PI and is now doing a postdoc at Radboud University Nijmegen in the Netherlands. In the above video he shares some of his highlights of the conference.

Gryb is working on “shape dynamics”, which is a new idea for re-evaluating Albert Einstein’s general theory of relativity (GR). The idea was initiated by Julian Barbour and Gryb became involved in the development of shape dynamics while he was at PI. He now belongs to a small international band of physicists who are developing the concept. While shape dynamics is an alternative treatment of GR, the ultimate goal of their work seems to be the creation of a new framework for a theory of quantum gravity – an important goal of theoretical physics.

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