Some features around the perimeter of the Balgesvarri plateau ice cap are described. Sorted stone circles were found beneath a slowly retreating ice margin, the basal ice in this area appears to be below the pressure-melting point. No absolute dating of features was possible but a relative chronology is suggested. RESUME. Le retrait glaciaire et les manifestations piriglaciaires sur les marges ...

Crater chronologies are a fundamental tool to assess relative and absolute ages of planetary surfaces when direct radiometric dating is not available. Martian crater derived from lunar spatial densities on terrains with known ages, thus they critically depend the extrapolation Moon Mars. This requires knowledge time evolution impact flux, including contributions various impactor populations, fa...

This is a brief survey of the current status of Stephen Hawking’s “chronology protection conjecture”. That is: “Why does nature abhor a time machine?” I’ll discuss a few examples of spacetimes containing “time machines” (closed causal curves), the sorts of peculiarities that arise, and the reactions of the physics community. While pointing out other possibilities, this article concentrates on t...

We test the chronology protection conjecture in classical general relativity by investigating finitely vicious space-times. First we present singularity theorems in finitely vicious space-times by imposing some restrictions on the chronology violating sets. In the theorems we can refer to the location of an occurring singularity and do not assume any asymptotic conditions such as the existence ...

We test the chronology protection conjecture in classical general relativity by investigating nitely vicious space-times. First we present singularity theorems in nitely vicious space-times by imposing some restrictions on the chronology violating sets. In the theorems we can refer to the location of an occurring singularity and do not assume any asymptotic conditions such as the existence of n...

We investigate the phenomenon of particle creation of the massless scalar field in the model of spacetime in which, depending on the model’s parameter ao, the chronology horizon could be formed. The model represents a two-dimensional curved spacetime with the topology R × S which is asymptotically flat in the past and in the future. The spacetime is globally hyperbolic and has no causal patholo...

with the publication of one complete edition of the journal expedition in 1989 on hasanlu project by american archaeologists, engaged there during pre-revolutionary period, the present study highlights some of the accepted mistakes in the explanation and interpretation of the facts in the articles of that journal on one hand, and the beginning of the activities by iranian archaeologists in 2000...