Gravitational waves detected for the first time

Credits: R. Hurt/Caltech-JPL In a historical scientific landmark, researchers have announced the first detection of gravitational waves, as predicted by Einstein's general theory of relativity 100 years ago. This major discovery opens a new era of astronomy. For the first time, scientists have directly observed "ripples" in the fabric of spacetime called gravitational waves, arriving at the Earth from a cataclysmic event in the distant universe. This confirms a major prediction of Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos. The observation was made at 09:50:45 GMT on 14th September 2015, when two black holes collided. However, given the enormous distance involved and the time required for light to reach us, this event actually occurred some 1.3 billion years ago, during the mid-Proterozoic Eon. For context, this is so far back that multicellular life here on Earth was only just beginning to spread. The signal came from the Southern Celestial Hemisphere, in the rough direction of (but much further away than) the Magellanic Clouds. The two black holes were spinning together as a binary pair, turning around each other several tens of times a second, until they eventually collided at half the speed of light. These objects were 36 and 29 times the mass of our Sun. As their...
Read More........

A Deep Look Into A Single Molecule

Credit: PTB The quantum state of a molecular ion has been measured live and in a non-destructive fashion for the first time. The interaction of thermal energy from the environment with motional degrees of freedom is well known and often referred to as Brownian motion (also thermal motion). But in the case of polar molecules, the internal degrees of freedom - in particular the rotational quantum state - are also influenced by the thermal radiation. So far, the detection of the rotational state was only possible by destroying the molecule. However, a German research group has now demonstrated the first implementation of a non-destructive state detection technique for molecular ions. Piet Schmidt and his colleagues from the QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB) observed changes in the rotational state of a trapped and indirectly cooled molecular ion in real time and in situ. This technique enables novel spectroscopy methods with applications ranging from chemistry to tests of fundamental physics. The results are published in the current issue of "Nature". Basic concept of the experiment: MgH+ (orange) and Mg+ (green) are trapped together in a linear ion trap. The two-ion compound is cooled to the motional ground state via the atomic ion. An oscillating dipole force changes the motional state according...
Read More........