The Open Physics Project


General Physics(1)

Evidence for Dark Energy

Reported from arXiv.Scientists have long been postulating about and searching for so called Dark Energy which is supposed to be gravitationally repulsive Dark Energy. A team of scientist at the University of Pittsburgh have found what can possibly be regarded as evidence for the existence of such energy. When photons fly past galaxies, attractive gravitational forces pull them slightly closer and lead to a gain in energy, it is supposed to loose precisely the same amount of energy it gained from this pull, when it flied away. However observations of the energy of such photons (the Cosmic Background Radiation> has revealed that photons nears massive bodies like galaxies generally have higher energies than photons which are not in such regions. Scranton and his team believe that this gain in energy is because of the repulsion caused by dark energy. (More soon....)

Submarine Sinks at the Speed of Light

A Brazilian physicist has resolved a paradox thrown up by Einstein's theory of relativity by using gravity. The theory of relativity states that at speed near that of light a length contraction takes place. Now suppose you have a submarine going at the speed of light. To the stationary observer it will appear as if the submarine gets shorter, hence denser and should sink, however from the point of view of the submariners, the water gets denser and hence because of increased buoyancy the submarine should come up to the surface. According to the theory of relativity both viewpoints are correct and the question which comes up is does the submarine actually sink or float. A Brazilian physicist has said the submarine sinks because while there is increased buoyancy, the net gravitational force on the submarine also increases and hence there is a net downward force which causes it to sink.

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