Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


E really does equal mc2 !


One of the most striking predictions of Einstein’s theory of special relativity is probably the best known formula in all science: E = mc2. Today, exactly one hundred years after its first formulation, this equivalence has been verified to be correct at least to an accuracy of 4 parts in 10 000 000 ! These measurements, at the Institut Laue-Langevin, Grenoble, and the Massachussets Institute of Technology (MIT), represent the most precise verification of the relation between mass and energy ever achieved.

The GAMS4 instrument. Copyright ILL / Artechnique

The direct test of Einstein’s equation is based on the prediction that when a nucleus captures a neutron, the resulting isotope (mass number A+1) is somewhat lighter than the sum of the masses of the original nucleus (mass number A) and the free neutron (mass number 1). The energy equivalent to this mass difference is emitted as a spectra of gamma-rays.

The mass difference in Einstein’s equation using two silicon isotopes 28-29Si and two sulphur isotopes 32-33S has been measured with very high accuracy on one side of the Atlantic at the MIT, using a novel experimental technique [2].

In parallel, on the other side of the Atlantic at the ILL, the energies of the gamma-rays emitted after neutron capture by both silicon and sulphur, have been measured by an international research team from the National Institute of Technologies and the Institut Laue-Langevin in Grenoble, using the world’s highest resolution gamma-ray interferometer GAMS4 [3]. Thanks to the combination of the very high neutron flux available at the ILL reactor and the exceptional energy resolution of the GAMS4 instrument, it was possible to determine the gamma-ray energies with a precision of better then 5 parts in 10 000 000.

From the comparison between the two values obtained on each side of the Atlantique - the mass difference measurements in America and the energy measurements in Europe -, it was possible to verify Einstein’s equation directly with a precision 55 times more accurate than existing measurements.

Even the most minute deviation from exact equality between energy and mass would have far reaching consequences for the whole of physics as it is today, from an understanding of the building blocks of matter to the evolution of the universe itself. The power of world-leading international collaborations of this kind, using the best facilities throughout the world, are needed to probe ever deeper into the mysteries of science.

Françoise Vauquois | alfa
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>