Physics

For the past three years a satellite has circled the Earth, collecting data to determine whether two predictions of Albert Einstein's general theory of relativity are correct.

Researchers have successfully applied X-ray scattering techniques to determine how dissolved metal ions interact in solution.

These findings will help researchers better understand how metal ions, such as those found in nuclear waste and other industrial processes, behave in the environment.


Researchers at the Department of Energy's Argonne National Laboratory and the University of Notre Dame have successfully applied X-ray scattering techniques to determine how dissolved metal ions interact in solution. Credit: Argonne National Laboratory

Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. Speed is the key - the transfer of the solar energy takes place almost instantaneously so little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a long-standing mystery that may have finally been solved.


Sunlight absorbed by bacteriochlorophyll (green) within the FMO protein (gray) generates a wavelike motion of excitation energy whose quantum mechanical properties can be mapped through the use of two-dimensional electronic spectroscopy.

Scientists of the MiniBooNE [1] experiment at the Department of Energy's Fermilab [2] today (April 11) announced their first findings. The MiniBooNE results resolve questions raised by observations of the LSND [3] experiment in the 1990s that appeared to contradict findings of other neutrino experiments worldwide.

Scientists from the Universities of Liverpool and Glasgow have completed work on the inner heart of an experiment which seeks to find out what has happened to all the antimatter created at the start of the Universe. Matter and antimatter were created in equal amounts in the Big Bang but somehow the antimatter disappeared resulting in the Universe, and everything in it, including ourselves, being made of the remaining matter.

The first sector of CERN* 's Large Hadron Collider (LHC) to be cooled down has reached a temperature of 1.9 K (-271°C), colder than deep outer space! Although just one-eighth of the LHC ring, this sector is the world's largest superconducting installation. The entire 27-kilometre LHC ring needs to be cooled down to this temperature in order for the superconducting magnets that guide and focus the proton beams to remain in a superconductive state. Such a state allows the current to flow without resistance, creating a dense, powerful magnetic field in relatively small magnets. Guiding the two proton beams as they travel at nearly the speed of light, curving around the accelerator ring and focusing them at the collision points is no easy task.

Using a laser-cooling technique that could one day allow scientists to observe quantum behavior in large objects, MIT researchers have cooled a coin-sized object to within one degree of absolute zero.

This study marks the coldest temperature ever reached by laser-cooling of an object of that size, and the technique holds promise that it will experimentally confirm, for the first time, that large objects obey the laws of quantum mechanics just as atoms do.


MIT researchers have developed a technique to cool this dime-sized mirror (small circle suspended in the center of large metal ring) to within one degree of absolute zero. Photo / Christopher Wipf

Livermore researchers have moved one step closer to being able to turn on and off the decay of a nuclear isomer.

The protons and neutrons in a nucleus can be arranged in many ways. The arrangement with the lowest energy is called the ground state and all others are called excited states. (This is analogous to the ground and excited states of electrons in an atom except that nuclear excited states are typically thousands of times higher in energy.) Excited nuclear states eventually decay to the ground state via gamma emission or to another nucleus via particle emission. Most excited states are short-lived (e.g., billionth of a second). However, a few are long-lived (e.g., hours) and are called isomers.

The last quadripolar magnet was brought down into the tunnel of the world’s largest particle accelerator; the CERN’s1 LHC, or Large Hadron Collidor. This magnet is part of a series of 392 units which will ensure that the beams are kept on track all along their trajectory through the tunnel. Its installation marks the completion of a long and fruitful collaboration between the CERN, the CNRS/IN2P32 and the CEA/DSM3 in the field of superconductivity and advanced cryogenics. This collaboration has lasted over ten years and was part of the special contribution made by France, as the host country, to the construction of the LHC.

Using measurements of the four ESA's Cluster satellites, a study published this week in Nature Physics shows pioneering experimental evidence of magnetic reconnection also in turbulent 'plasma' around Earth.


This image provides a model of magnetic fields at the Sun's surface using SOHO data, showing irregular magnetic fields (the ‘magnetic carpet’) in the solar corona (top layer of the Sun's atmosphere). Small-scale current sheets are likely to form in such turbulent environment and reconnection may occur in similar fashion as in Earth's magnetosheath. Credits: Stanford-Lockheed Inst. for Space Research/NASA GSFC