Results 41 to 50 of about 8,442 (193)
Electrons in the cosmic radiation [PDF]
, 1990 The nature of cosmic ray electrons and their radiation in the Universe has been studied. A convection associated diffusion model is proposed to describe the main characteristics of the large-scale distribution of cosmic ray electrons in the Galaxy: (1) a
Chi, Xinyu, Chi, X
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The Great Cosmic Silence: What Does the Fermi Paradox Tell About the Future of Humanity?
Global Policy, EarlyView.ABSTRACT This article examines how institutional time horizons shape the long‐term survival prospects of human technological civilisation. While research on global catastrophic and existential risks has expanded, the temporal structures of political‐economic institutions remain underexamined.
Heikki Patomäki
wiley +1 more source
Meteoritics &Planetary Science, EarlyView.Abstract Amorphous carbon (αC) is found in various extraterrestrial particles, including those thought to originate from the outer Solar System. αC can form through two main processes involving C‐rich materials: exposure to energetic charged particles and thermal processing.
M. Germanà +10 more
wiley +1 more source
Journal of Physics: Conference Series, 2006 In this brief review we describe the theory of the origin of Galactic cosmic rays. The concept that interaction near the source is the dominant source of ?-rays, and spallation secondaries seems best suited to explain the EGRET ?-spectrum of the inner Galaxy, the abundances of light elements, the anti-protons and the positrons.
openaire +1 more source
Nanoscale space weathering features in mature lunar soil revealed by TEM and APT
Meteoritics &Planetary Science, EarlyView.Abstract Space weathering significantly alters the optical, chemical, and structural properties of lunar regolith at micro‐ and nanoscales; yet detailed nanoscale variability within individual soils remains underexplored. Here we apply transmission electron microscopy (TEM) and atom probe tomography to four mineral grains (olivine, ilmenite, and two ...
Jennika Greer +6 more
wiley +1 more source
Potassium isotopic compositions and exposure ages of evolved and silica‐rich achondrites
Meteoritics &Planetary Science, EarlyView.Abstract Some of the oldest igneous rocks in the Solar System include evolved and silica‐rich achondrites that originate from parent bodies less than 1000 km in diameter, referred to as planetesimals. While Earth was initially in a molten state and required continental crust formation and plate tectonics to generate andesite bulk compositions, evolved ...
Z. Vaci +9 more
wiley +1 more source
Very high energy gamma ray observations of southern hemisphere blazars [PDF]
, 1997 This thesis is concerned with very high energy γ-ray observations of blazars observable from the southern hemisphere. The data presented were obtained using the recently deployed University of Durham Mark 6 high sensitivity Čerenkov telescope. Chapters 1
Dickinson, M.R., Dickinson, Mark R.
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Galactic Cosmic Rays - Theory and Interpretation [PDF]
, 2017 The arguments surrounding the Galactic component of the cosmic rays, the energy budget, ques- tions of composition, spectral features, anisotropy, sources etc, will be critically examined.
Luke Drury MRIA, Drury, Luke O'Connor
core +1 more source
The 40K‐K dating system: 1. Improving data interpretation using new model calculations
Meteoritics &Planetary Science, EarlyView.Abstract The 40K‐K cosmic‐ray exposure (CRE) dating system offers a promising method for determining exposure ages of iron meteorites by combining the radioactive cosmogenic 40K with the stable cosmogenic isotopes 39K and 41K. However, earlier applications relied on semi‐empirical production models and inconsistent analytical data sets, limiting their ...
Farshid Nozarian +2 more
wiley +1 more source
A study of radio continuum emission of the Milky Way Galaxy [PDF]
, 1996 The synchrotron emissivity distribution of the Milky Way Galaxy has been modelled from the 408 MHz allsky survey of Haslam et al.(1982) after separation of its thermal component with the help of IRAS 60 micron emission(Broadbent et al 1989).
Sanguansak, Nuanwan
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