منابع مشابه
Cosmic questions: an introduction.
This introductory talk at the Cosmic Questions conference sponsored by the AAAS summarizes some earlier pictures of the universe and some pictures based on modern physics and cosmology. The uroboros (snake swallowing its tail) is an example of a traditional picture. The Biblical flat-earth picture was very different from the Greek spherical earth-centered picture, which was the standard view un...
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We briefly discuss three aspects related to the origin of ultra-high energy cosmic rays (UHECRs) namely: 1) particle acceleration in astrophysical sources; 2) transition to an extragalactic origin; 3) spectrum and anisotropies at the highest energies.
متن کاملCosmic Rays: Recent Progress and some Current Questions
A survey of progress in recent years suggests we are moving towards a quantitative understanding of the whole cosmic ray spectrum, and that many bumps due to different components can hide beneath a smooth total flux. The knee is much better understood: the KASCADE observations indicate that the spectrum does have a rather sharp rigidity cut-off, while theoretical developments (strong magnetic f...
متن کاملTime Delays in Cosmic Ray Propagation
Cosmic Rays (CR) travel at speeds essentially indistinguishable from the speed of light. However whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. Those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. Fu...
متن کاملProbing decisive answers to dark energy questions from cosmic complementarity and lensing tomography
We study future constraints on dark energy parameters determined from several combinations of cosmic microwave background experiments, supernova data, and cosmic shear surveys with and without tomography. In this analysis, we look in particular for combinations of experiments that will bring the uncertainties to a level of precision tight enough (a few percent) to answer decisively some of the ...
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ژورنال
عنوان ژورنال: Nature
سال: 1980
ISSN: 0028-0836,1476-4687
DOI: 10.1038/288034b0