### Atomic clocks prove the stability of a fundamental physical constant

Are the fundamental constants really constant? Recent investigations carried out at the Physikalisch-Technische Bundesanstalt (PTB) have shown that one essential fundamental constant – namely the mass ratio ...

### What is the value of G?

NIST has taken part in a new push to address a persistent and growing problem in physics: the value of G. The Newtonian constant of gravitation, used to calculate the attractive force of gravity between objects, is more than ...

### Physical constant is constant even in strong gravitational fields

An international team of physicists has shown that the mass ratio between protons and electrons is the same in weak and in very strong gravitational fields. Their study, which was partly funded by the FOM ...

### Variables of nature

Within physics there are certain physical quantities that play a central role. These are things such as the mass of an electron, or the speed of light, or the universal constant of gravity. We aren't sure ...

### Graphene joins the race to redefine the ampere

A new joint innovation by the National Physical Laboratory (NPL) and the University of Cambridge could pave the way for redefining the ampere in terms of fundamental constants of physics. The world's first ...

### Dark energy alternatives to Einstein are running out of room

(Phys.org)—Research by University of Arizona astronomy professor Rodger Thompson finds that a popular alternative to Albert Einstein's theory for the acceleration of the expansion of the universe does not ...

### Optical strontium clock to become much more accurate

(Phys.org)—An optical clock with neutral strontium atoms is considered one of the top candidates for the definition of a "new" second. The probabilities have increased considerably, since its frequency ...

### Alcohol constrains physical constant in the early universe

(Phys.org)—Radio-astronomical observations of a distant galaxy indicate that the ratio of the proton's mass to that of the electron has hardly changed over cosmic history. This fundamental constant of nature ...

### Researchers racing to develop world's most accurate thermometer

The University of Queensland (UQ) physicists are on a quest to build the world's most accurate thermometer.

### Atomic clock comparison via data highways

(Phys.org) -- Optical atomic clocks measure time with unprecedented accuracy. However, it is the ability to compare clocks with one another that makes them applicable for high-precision tests in fundamental ...

### Is graphene the best quantum resistance standard?

New research from NPL's Quantum Detection Group presents the most precise measurements of the quantum Hall effect ever made, using the two-dimensional material graphene.

### The constants they are a changin': NIST posts latest adjustments to fundamental figures

The electromagnetic force has gotten a little stronger, gravity a little weaker, and the size of the smallest "quantum" of energy is now known a little better. The National Institute of Standards and Technology ...

### First app from NPL to help researchers working in the lab

The UK's National Physical Laboratory (NPL) has released its first app for iOS devices such as iPhones and iPads. It will provide researchers with easy and up-to-date access to the values for all the physical constants.

### Accurate Avogadro constant may help redefine the kilogram

(PhysOrg.com) -- A new accurate determination of the Avogadro constant has used the method of "counting" the atoms in a 1 kg sample of an almost perfect silicon sphere highly enriched with the isotope 28Si. They used ...