Newton tops PhysicsWeb poll
Almost 400 people took part in the PhysicsWeb poll, each one naming their top-five physicists. The votes for each physicist were added up and weighted according to how they were ranked by individual v...
More evidence for the accelerating universe
The first evidence for the accelerating universe came from observations of distant supernovae. However, the data were also consistent with an open universe – a universe that would expand forever...
Dropping atoms gives precise value of g
Atomic interferometers use lasers to place atoms into superpositions of different quantum states. These states acquire different phases as they move in a gravitational field, and this phase difference...
Gravity-wave detectors target quantum gravity
Both the French-Italian gravity-wave interferometer, called VIRGO, and the LIGO interferometers in the US are designed to detect very weak gravity waves by using lasers to monitor test masses placed a...
Solar system is chaotic
Murray and Holman ran numerical simulations of the planets positions over a 200 million year period using their new technique. They discovered that although the outer planets appear in stable orbits, ...
Science chooses accelerating universe as “Breakthrough of the Year”
Astronomers have known for decades that the universe is expanding, based on measurements of the “red shift” of light emitted by galaxies. According to the standard cosmological model, ther...
Taking a closer look at “big G”
The gravitational constant was first measured by Lord Cavendish in 1798, who used a torsion-balance to measure the force between a pair of lead spheres. Cavendish measured G to be 6.754 x 10-11 metres...
Evidence mounts that the expansion of the Universe is accelerating
Astronomers have been puzzling over the expansion rate of the Universe and its mass for decades. If the mass of the Universe is large enough, the expansion will eventually decrease and the Universe wi...
Making light work of gravity gradients
The interferometer was built by Mark Kasevich and colleagues at Yale University in the US and used individual atoms, rather than macroscopic man-made objects, to measure the gradient. By observing the...
Gamma-ray bursts could test quantum gravity
Gamma-ray bursts appear to be related to the deaths of massive stars. Amelino-Camelia and colleagues claim that if the difference in the arrival times of photons with different energies can be measure...
