Physics & Chemistry

X-rays: a century of discovery, diffraction, and dynamical theory

By Andre Authier

The International Year of Light provides a good opportunity to revisit the early studies on the optical properties of X-rays. X-rays were discovered by W. C. Röntgen on the evening of 8 November 1895 while he was redoing some of Hertz’s experiments on cathode rays. By the end of the year, even before informing the world of his discovery, he had observed the basic properties of X-rays: like light, they propagate as straight lines and are diffused by turbid media, but are not deflected by a prism, nor refracted or reflected by matter; they pass through bodies, as shown by the radiograph of his wife’s hand.

Alhazen’s problem

By Stephen R. Wilk

One of the reasons that 2015 has been declared the International Year of Light is that it marks the 1000th year since the publication of Kitāb al-Manāẓir, The Treasury of Optics, by the mathematician and physicist Abu Ali al-Hasan ibn al-Hasan ibn al-Haitham, better known in Western cultural history as Alhazen. Born in Basra in present-day Iraq, he is acknowledged as the most important figure in optics between the time of Ptolemy and of Kepler, yet he is not known to most physicists and engineers.

Beyond Budapest: how science built bridges

By Istvan Hargittai and Magdolna Hargittai

Fin de siècle Hungary was a progressive country. It had limited sovereignty as part of the Austro-Hungarian dual monarchy, but industry, trade, education, and social legislation were rapidly catching up with the Western World. The emancipation of Jews freed tremendous energies and opened the way for ambitious young people to the professions in law, health care, science, and engineering (though not politics, the military, and the judiciary). Excellent secular high schools appeared challenging the already established excellent denominational high schools.

Bizarre elements: a timeline

By Marco Fontani, Mariagrazia Costa, and Mary Virginia Orna

The periodic table has experienced many revisions over time as new elements have been discovered and the methods of organizing them have been solidified. Sometimes when scientists tried to fill in gaps where missing elements were predicted to reside in the periodic table, or when they made even the smallest of errors in their experiments, they came up with discoveries—often fabricated or misconstrued—that are so bizarre they could have never actually found a home in our current version of the periodic table.

Living with the Stars – Episode 20 – The Oxford Comment

Everything is connected. Animals and asteroids, bodies and stardust, heart valves and supernovas—all of these rise from the same origin to form the expanse of the universe, the fiber of our being. So say our guests of this month’s Oxford Comment, Karel Shrijver, an astronomer who studies the magnetic fields of stars, and Iris Schrijver, a physician and pathologist. We sat down for a captivating discussion with the co-authors of Living with the Stars: How the Human Body is Connected to the Life Cycles of the Earth, the Planets, and the Stars.

Stephen Hawking, The Theory of Everything, and cosmology

By Mary-Teresa Madders

Renowned English cosmologist Stephen Hawking has made his name through his work in theoretical physics as a bestselling author. His life – his pioneering research, his troubled relationship with his wife, and the challenges imposed by his disability – is the subject of a poignant biopic, The Theory of Everything. Directed by James Marsh, the film stars Eddie Redmayne, who has garnered widespread critical acclaim for his moving portrayal.

That’s relativity

By Keith Mansfield

A couple of days after seeing Christopher Nolan’s Interstellar, I bumped into Sir Roger Penrose. If you haven’t seen the movie and don’t want spoilers, I’m sorry but you’d better stop reading now.
Still with me? Excellent. Some of you may know that Sir Roger developed much of modern black hole theory with his collaborator, Stephen Hawking, and at the heart of Interstellar lies a very unusual black hole. Straightaway, I asked Sir Roger if he’d seen the film. What’s unusual about Gargantua, the black hole in Interstellar, is that it’s scientifically accurate.

Five tips for women and girls pursuing STEM careers

By Mariangiola Dezani

Many attempts have been made to explain the historic and current lack of women working in STEM fields. During her two years of service as Director of Policy Planning for the U. S. State Department, from 2009 to 2011, Anne-Marie Slaughter suggested a range of strategies for corporate and political environments to help better support women at work. These spanned from social-psychological interventions to the introduction of role models and self-affirmation practices.

Are the mysterious cycles of sunspots dangerous for us?

By Arnab Rai Choudhuri

Galileo and some of his contemporaries left careful records of their telescopic observations of sunspots – dark patches on the surface of the sun, the largest of which can be larger than the whole earth. Then in 1844 a German apothecary reported the unexpected discovery that the number of sunspots seen on the sun waxes and wanes with a period of about 11 years. Initially nobody considered sunspots as anything more than an odd curiosity.

Celebrating women in STEM

By Charley James

It is becoming widely accepted that women have, historically, been underrepresented and often completely written out of work in the fields of Science, Technology, Engineering, and Mathematics. Explanations for the gender gap in STEM fields range from genetically-determined interests, structural and territorial segregation, discrimination, and historic stereotypes. With free Oxford University Press content, we tell the stories and share the research of both famous and forgotten women.

Of black holes, naked singularities, and quantum gravity

By Pankaj S. Joshi

Modern science has introduced us to many strange ideas on the universe, but one of the strangest is the ultimate fate of massive stars in the Universe that reached the end of their life cycles. Having exhausted the fuel that sustained it for millions of years of shining life in the skies, the star is no longer able to hold itself up under its own weight, and it then shrinks and collapses catastrophically unders its own gravity. Modest stars like the Sun also collapse at the end of their life, but they stabilize at a smaller size.

Time as a representation in physics

By A. R. P. Rau

A previous piece (“Patterns in Physics”) discussed alternative “representations” in physics as akin to languages, an underlying quantum reality described in either a position or a momentum representation. Both are equally capable of a complete description, the underlying reality itself residing in a complex space with the very concepts of position/momentum or wave/particle only relevant in a “classical limit”. The history of physics has progressively separated such incidentals of our description from what is essential to the physics itself.

Physics Project Lab: How to create the domino effect

By Paul Gluck

Many dominoes may be stacked in a row separated by a fixed distance, in all sorts of interesting formations. A slight push to the first domino in the row results in the falling of the whole stack. This is the domino effect, a term also used in figuratively in a political context. You can use this amusing phenomenon to carry out a little project in physics.

Stardust making homes in space

By Iris Schrijver and Karel Schrijver

Although we rarely stop to think about the origin of the elements of our bodies, we are directly connected to the greater universe. In fact, we are literally made of stardust that was liberated from the interiors of dying stars in gigantic explosions, and then collected to form our Earth as the solar system took shape some 4.5 billion years ago.

The shape of our galaxy

By Alex R. Pettitt

Many of you have likely seen the beautiful grand spiral galaxies captured by the likes of the Hubble space telescope. Images such as those below of the Pinwheel and Whirlpool galaxies display long striking spiral arms that wind into their centres.

Physics Project Lab: How to investigate the phenomena surrounding rubber bands

By Paul Gluck

Rubber bands are unusual objects, and behave in a manner which is counterintuitive. Their properties are reflected in characteristic mechanical, thermal and acoustic phenomena. Such behavior is sufficiently unusual to warrant quantitative investigation in an experimental project. A well-known phenomenon is the following. When you stretch a rubber band suddenly and immediately touch your lips with it, it feels warm, the rubber band gives off heat.