One of the most famous photographs from the history of physics, showing the participants of the 1927 Solvay Conference in Brussels, Belgium, discussing "Electrons and Photons."

Front row, from the left: Langmuir, Planck, Curie, Lorentz, Einstein, Langevin, Guye, Wilson, Richardson. Second row: Debye, Knudsen, Bragg, Kramers, Dirac, Compton, de Broglie, Born, Bohr. Standing: Piccard, Henriot, Ehrenfest, Herzen, De Donder, Schroedinger, Verschaffelt, Pauli, Heisenberg, Fowler, Brillouin. 

The Personalities of Quantum Theory

The 1927 Solvay Conference in Brussels, Belgium, brought together the world's leading quantum physicists to discuss "Electrons and Photons." Of the 29 conference participants, 17 were or would eventually become Nobel Laureates. A recently discovered video clip, shot by Irving Langmuir - the winner of the Nobel Prize in chemistry in 1932 - captures 21 of the conference members. A beautiful thing.

The Story of Madame Curie

Marie Curie was the first woman to receive a Nobel Prize, and the first scientist, man or woman, to be awarded a second one. These recognitions were awarded for her work on radioactivity and her discovery of two chemical elements: radium and polonium (named after her native Poland). Marie Curie lived a life marked by financial hardship (she entered a pact with her sister whereby Marie would work as a governess to finance her sister's medical degree, upon which her sister would support Marie's studies at the Sorbonne), tragedy (her mother and sister died early of disease, and her beloved husband Pierre was killed in a tragic accident), and disease (a consequence of her long-term exposure to radioactivity). However, she was a woman with an immense determination and dedication to her work, which, against her own desires, brought her tremendous fame and recognition. Her story, presented here in relative brevity, is certainly one worth the read.

View of the "Cosmic Web," the rich population of halos connected by dark matter seen in the Millennium Simulation. 

Close-up view of one of the many galaxy clusters formed in the Millennium Simulation 

Large-Scale Structure in the Universe

The emergence of large-scale structure from the small density fluctuations in the early Universe (as evident from CMB observations) is one of the greatest challenges in contemporary cosmology. In our current understanding of the matter content of the Universe, ~85% of the matter in the Universe exists in the form of dark matter, a weakly interacting particle that remains unidentified. Initial fluctuations in this matter, amplified by gravity during the expansion of the Universe, eventually collapsed to form the galaxies seen in the Universe today. Modeling this process is done by representing the matter as a collisionless N-body system evolving under self-gravity.

The largest simulation of this kind was recently carried out by physicists at the Max Planck Institute for Astrophysics, whose simulation included 10 billion particles (an order of magnitude greater than any previous simulation) in a periodic box simulation volume of 500 Mpc/h to a side, resulting in a particle mass of 860 million/h solar masses. Thereby, dwarf galaxies were represented by ~100 particles, galaxies like the Milky Way by ~1000 particles, and rich galaxy clusters by several million particles. The results of this simulation, named the Millennium Simulation, are illustrated in the above images. The simulations show a rich population of halos, connected to each other by dark matter filaments. This structure has been named the "Cosmic Web," as seen in the top image above. In the bottom image, one of the rich galaxy clusters created in the simulation can be seen.

Some absolutely unbelievable animations of these simulations are shown here. Note that many of these visualizations are .avi files, so you may need to view them with e.g. VLC Media Player.

Hubble-Spitzer composite image of M104 - The Sombrero Galaxy (www.spitzer.caltech.edu/spitzer/) 

The Early Days of the Big Bang Theory

In honor of the World Year of Physics, Physical Review is republishing archive papers related to Einstein's 1905 accomplishments. By the 1940's, Hubble's measurements of the receding velocities of distant galaxies had established that the Universe was expanding and had existed in a more dense state in the past. In 1948, Alpher, Bethe, and Gamow (the two collaborators allegedly chosen by Gamow because their collective names sounded like the three first letters of the Greek alphabet alpha, beta, and gamma) proposed that the Universe began in the form of a neutron fluid, which would decay into protons and electrons as it expanded, allowing elements like deuterium, helium, and lithium to form. Although the picture of the early Universe was to change considerably over the following decades, the Alpher, Bethe, and Gamow paper continued to have considerable historical influence over future work in the area.

New Meson Discovered

Physicists at the KEK laboratory in Japan believe they have discovered a new meson. This new particle was believed to have been created during an electron-positron collision, before quickly decaying into the well-known Omega and J/Psi mesons. Based on this decay mode, the physicists believe the new meson consisted of a charm quark, a charm anti-quark, and a gluon. The existence of this particle was first postulated in 1978, however, because the mass of the newly discovered particle is significantly lower than the predicted mass, further research will need to be conducted.

The Stars, the Galaxy, the Universe...

...have inspired humans since the dawn of our existence. And while philosophers and scientists pondered the laws governing the Universe, the poets immortalized their fascination with it in art.
In searching for an appropriate poem with which to embellish my thesis (on the formation of the Milky Way), I came upon several sites dedicated to astronomy in poetry. If French comes naturally to you, I highly recommend L'astronomie et la poesie, a wonderful site with poetry in both French and English.

Star Formation

Science Education

Perhaps a bit unusual, but an important insight into the reality of science education in US high schools.