It’s another Sunday and for those bored of watching football here are the top news stories of the last week. As always, if you would like to receive these stories straight to your email box, register for our email newsletter. Also, for more news, check out the news section.
By now it’s almost a yearly tradition for someone to “discover” that the speed of light is higher than allowed by the rules of relativity, however, the claim that it might be slower is indeed a unique one. Recently, physicist James Franson of the University of Maryland has captured the attention of the physics community by posting an article to the peer-reviewed New Journal of Physics in which he claims to have found evidence that suggests the speed of light as described by the theory of general relativity, is actually slower than has been thought.
Franson’s idea comes from the observational data of the supernova SN 1987A that exploded back in 1987. What’s unique about this supernova is that the photons coming from it were detected 4.7 hours late. At the time it was attributed to a different source, but Franson believes this time difference could be explained by a property called vacuum polarization — when a photon splits into a positron and an electron, for a very short time before recombining back into a photon. If Franson’s ideas turn out to be correct, many cosmological theories would have to be re-written. However, for that to happen, more observations with light lagging behind the currently accepted speed limit will be required.
What is believed to be the smallest force ever measured has been detected by researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley. Using a combination of lasers and a unique optical trapping system that provides a cloud of ultracold atoms, the researchers detected a force of approximately 42 yoctonewtons.
“We applied an external force to the center-of-mass motion of an ultracold atom cloud in a high-finesse optical cavity and measured the resulting motion optically,” says Dan Stamper-Kurn. “When the driving force was resonant with the cloud’s oscillation frequency, we achieved a sensitivity that is consistent with theoretical predictions and only a factor of four above the Standard Quantum Limit, the most sensitive measurement that can be made.”
The top of a 3,000m-high (10,000ft) mountain in Chile has been blown up to make way for the world’s largest optical and infrared telescope. The European-Extremely Large Telescope will find its home on the top of the hill housing a mirror that is half the size of a football pitch. This new telescope will allow astronomers to look further into space and in more detail than ever before. “The telescope is a really huge step in terms of its scale – it’s so much bigger than anything else,” said Dr Aprajita Verma, the deputy project scientist for the E-ELT’s UK team. “It will give us a deeper and finer view of the Universe.”