Particles Travel Faster Than Light

Neutron, illustration

Physicists reported that sub-atomic particles called neutrinos can travel faster than light, a finding that - if verified - would blast a hole in Einstein's theory of relativity.


Physicists have found that tiny particles called neutrinos are making a 454-mile (730-kilometer) underground trip faster than they should — more quickly, in fact, than light could do. If the results are confirmed, they could throw much of modern physics into upheaval.


In experiments conducted between the European Centre for Nuclear Research (CERN) in Switzerland and a laboratory in Italy, the tiny particles were clocked at 300,006 kilometres per second, about six km/sec faster that the speed of light, the researchers said.


"This result comes as a complete surprise" said physicist Antonio Ereditato, spokesman for the experiment, known as OPERA. "We wanted to measure the speed of neutrinos, but we didn't expect to find anything special."


Results from the CERN laboratory in Switzerland seem to break this cardinal rule of physics, calling into question one of the most trusted laws discovered by Albert Einstein.

Speed of Light, illustration

Scientists spent nearly six months "checking, testing, controlling and rechecking everything" before making an announcement.


Researchers involved in the experiments were cautious in describing its implications, and called on physicists around the world to scrutinise their data, to be made available online overnight.


But the findings, they said, could potentially reshape our understanding of the physical world.


"If this measurement is confirmed, it might change our view of physics" said CERN research director Sergio Bertolucci, a view echoed by several independent physicist contacted by AFP.


In the experiments, scientists blasted a beam producing billions upon billions of neutrinos from CERN, which straddles the French-Swiss border near Geneva, to the Gran Sasso Laboratory 730 kilometres away in Italy.


Neutrinos are electrically neutral particles so small that only recently were they found to have mass.


"The neutrinos arrived 60 nanoseconds earlier that the 2.3 milliseconds taken by light" Ereditato told AFP.


Under Albert Einstein's theory of special relativity, however, a physical object cannot travel faster than the speed of light in a vacuum.


Newton's theory of gravity, still explains the movement of planets well enough to send missions into space, even if Einstein's theories proved that it was not quitecorrect.


Theoretical physicists are sure to begin searching for new explanations to account for the unsuspected quickness of neutrinos.


It could be that "the particles have found a shortcut in another dimension" besides the four - three in space, plus time - we know about.


"Or it could simply mean that the speed of light is not the speed limit we thought it was."

Metamaterial Sheets Make Invisibility Cloaks

Researchers at the University of Illinois at Urbana-Champaign have formulated a new method that can be used for large scale manufacturing of metamaterials. The metamaterials are alloys with slightly unusual properties. This class of materials can interact with light in a different manner. Some of these materials can be used for producing futuristic optical devices like invisibility cloaks, superlenses and other devices.


The prototypes for such state of the art gadgets have been already developed but the main problem is that these materials are hard to fabricate in large quantities. The new printing methodology is said to be able to manufacture sheets of metamaterials with dimensions large enough to create practical devices. Small sheets measuring hardly a few hundred nanometers were developed till now which were hardly sufficient for anything except laboratory demonstrations.


The team of scientists is led by John Rogers, professor of material engineering at the University of Illinois. Metamaterials have an intricate and complex molecular lattice. It has a layered structure with overlapping metal layers. The main constraint while designing these alloys is that the dimensions should be comparable to the wavelength of the light spectrum in which the material has to operate. Till now, complex techniques like electron beam lithography. Rogers and his group have developed a simpler alternative that is economically feasible. It is basically a stamp based printing technique that can be used for bigger pieces of metamaterials. Some of the substances belonging to this category of materials have a negative refractive index with respect to infrared light and hence do not reflect the incident light. This property makes it suitable for making super lenses, hi tech optical communication devices, night vision invisibility cloak, etc.


The fabrication process is pretty simple. Initially, the desires hard plastic stamp is shaped on which a fishnet like pattern of layer is embossed. This stamp is then placed in an evaporation chamber where it gets coated with alternative layers of sacrificial layer and metamaterials. The main metamaterial ingredients are oxides of magnesium and silver. In this way a mesh gets deposited on the stamp. Later, this stamp is placed on a plastic or glass plate. Then the sacrificial layer is etched away and the pattern is deposited on the glass layer. The size of the material can be increased by improving the stamp surface area and these stamp fabricated patterns have better optical characteristics.


Now, the most time consuming thing in this method is making the moulds for the stamps precisely. Once the mould is ready, any number of reusable stamps can be manufactured for the printing of metamaterial sheets. It might take a few more years for making this technology commercial. Let’s hope that this technology can make Harry Potter-like invisibility cloaks.