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"Everything should be as simple as it is, but not simpler", Albert Einstein
Browsing All posts tagged under »GRAVITY«
Anatomy of a fall: Giovanni Battista Riccioli and the story of g
Christopher M. Graney Every physics student learns about falling bodies and g, the acceleration due to Earth’s gravitational field. But few physicists learn the story of the first experiments—now more than three centuries old—to measure g. That story begins in earnest with the famed Italian astronomer Galileo Galilei. In his 1632 tome, Dialogue Concerning the […]
ALPHA weighs in on antimatter
April 30, 2013
Description and first application of a new technique to measure the gravitational mass of antihydrogen Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there […]
Probing gravity
July 30, 2012
Einstein’s theory of relativity is remarkable not only because it is so successful in explaining seemingly bizarre observations (like the bending of starlight) or because it has assembled a coherent picture of nature. One would expect these results from any good theory. Relativity is also amazing because its has shown that the universe behaves in […]
A New Exponential Gravity
April 2, 2012
Qiang Xu, Bin Chen We propose a new exponential f(R) gravity model with and n>3, 1≤λ, c>0 to explain late-time acceleration of the universe. At the high curvature region, the model behaves like the ΛCDM model. In the asymptotic future, it reaches a stable de-Sitter spacetime. It is a cosmologically viable model and can evade the […]
Getting the Swing of Surface Gravity
February 6, 2012
Brian C. Thomas & Matthew Quick Sports are a popular and effective way to illustrate physics principles. Baseball in particular presents a number of opportunities to motivate student interest and teach concepts. Several articles have appeared in this journal on this topic, illustrating a wide variety of areas of physics. In addition, several websites and […]
Flies walk on air in levitation experiment
January 4, 2012
Scientists have used magnetic fields to ‘levitate’ flies in the first weightless tests conducted outside space The technique, known as ”diamagnetic levitation”, allows water and organic based materials to become weightless. Floating freely inside a plastic tube, the flies were observed closely to spot any changes in their behaviour. The scientists confirmed effects previously seen […]
Falling atoms measure the Earth’s rotation
October 7, 2011
A new type of gyroscope based on interfering atoms has been developed that can determine the latitude where the instrument is located – and also measure true north and the Earth’s rate of rotation. The device has been developed by physicists in the US, who hope to scale it up so that it can test […]
Solar Interior May Reveal Modifications to Gravity
September 6, 2011
We know lots about gravity in a vacuum but very little about gravity inside extremely massive objects. But astrophysicists say the Sun could reveal all Einstein’s theory of general relativity is one of the cornerstones of modern physics. As such, it is unquestionably a towering achievement. And yet it also raises uncomfortable questions for physicists. The […]
Testing black hole no-hair theorem with OJ287
September 3, 2011
We examine the ability to test the black hole no-hair theorem at the 10% level in this decade using the binary black hole in OJ287. In the test we constrain the value of the dimensionless parameter q that relates the scaled quadrupole moment and spin of the primary black hole: q2 = −q χ^2. At the […]
Experiments Show Gravity Is Not an Emergent Phenomenon
August 24, 2011
The way gravity effects quantum particles proves that it cannot be an emergent phenomenon, says physicist. One of the most exciting ideas in modern physics is that gravity is not a traditional force, like electromagnetic or nuclear forces. Instead, it is an emergent phenomenon that merely looks like a traditional force. This approach has been […]
52 Years and $750 Million Prove Einstein Was Right
May 7, 2011
In a tour de force of technology and just plain stubbornness spanning half a century and costing more than $750 million, a team of experimenters from Stanford University reported on Wednesday that a set of orbiting gyroscopes had detected a slight sag and an even slighter twist in space-time. The finding confirms some of the […]
May 5, 2013
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