### 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 ...

### 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 ...

### Variations in fine-structure constant suggest laws of physics not the same everywhere

(PhysOrg.com) -- One of the most controversial questions in cosmology is why the fundamental constants of nature seem fine-tuned for life. One of these fundamental constants is the fine-structure constant, ...

### 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 ...

### 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 ...

### 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 ...

### 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 ...

### Math theories may hold clues to origin, future of life in universe

How did we get here and where are we headed? These are some of life's biggest questions. To get the answers, one Kansas State University professor is doing the math.

### 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 ...

### 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 ...

### 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.