9,757 research outputs found
On the gravitational redshift
The study of the gravitational redshift\,---\,a relative wavelength increase
of was predicted for solar radiation by Einstein in
1908\,---\,is still an important subject in modern physics. In a dispute
whether or not atom interferometry experiments can be employed for
gravitational redshift measurements, two research teams have recently disagreed
on the physical cause of the shift. Regardless of any discussion on the
interferometer aspect\,---\,we find that both groups of authors miss the
important point that the ratio of gravitational to the electrostatic forces is
generally very small. For instance, the gravitational force acting on an
electron in a hydrogen atom situated in the Sun's photosphere to the
electrostatic force between the proton and the electron is approximately . A comparison of this ratio with the predicted and observed
solar redshift indicates a discrepancy of many orders of magnitude. Here we
show, with Einstein's early assumption of the frequency of spectral lines
depending only on the generating ion itself as starting point, that a solution
can be formulated based on a two-step process in analogy with Fermi's treatment
of the Doppler effect. It provides a sequence of physical processes in line
with the conservation of energy and momentum resulting in the observed shift
and does not employ a geometric description. The gravitational field affects
the release of the photon and not the atomic transition. The control parameter
is the speed of light. The atomic emission is then contrasted with the
gravitational redshift of matter-antimatter annihilation events.Comment: 19 Pages; 2 Table
Bottom Melting on the Filchner-Ronne Ice Shelf, Antarctica, Using Different Mesasuring Techniques
National economic impacts of an EU environmental policy: an applied general equilibrium analysis
The objective of this paper is to quantify the economic effects of the introduction of a system of tradable permits in the European Union (EU). For this purpose we use linked applied general equilibrium models (AGE) for eleven EU member countries. This method enables us to measure the change in competitiveness for domestic industries, the impact on growth, employment and inflation in member countries, and the cost and benefits of a cooperative approach to adhere to a EU target of emissions of air pollutants. The results we will present are first results from the SOLVGE/GEM-E3 Projekt. GEM-E3 stands for General Equilibrium Modeling for Energy - Economy - Environment, a joint undertaking of NTUA-Athens (P. Capros, P. Georgakopoulos), CESKULeuven (S. Proost and D. Van Regemorter), Univ. Mannheim and ZEW (K. Conrad and T. Schmidt), GEMME-CEA (N. Ladoux), Univ. Strathclyde (P. MacGregor), CORE-UCL (Y. Smeers), With respect to a policy on greenhouse gases we will quantify the economic impact for the, EU by introducing a EU-wide tradable permit system, free of charge and based on the present energy intensity and energy mix. Under growth there will be a positive market price for permits with demand by countries where the cost of substitution are high and supply by those countries where the cost of substitution are low. We will measure economic performance and trade flows under a noncoordinated CO2 policy where each country limits the emission of CO2 by 10% and will compare the result with a cooperative outcome where the European Union as a decision maker aims at reducing CO2 by 10%. --
- …