Results 81 to 90 of about 17,761 (262)

Confirming the impact origin of the São Miguel do Tapuio structure, northeastern Brazil

Meteoritics &Planetary Science, EarlyView.
Abstract The São Miguel do Tapuio structure (SMT) is a remarkable, nearcircular feature of about 21 km diameter, centered at 5°37.6′ S, 41°23.3′ W in Piauí state, northeastern Brazil. The structure is located within the sedimentary strata of the Paleozoic–Mesozoic Parnaíba Basin and predominantly comprises sandstones of the Devonian Pimenteiras and ...
Alvaro Penteado Crósta, Neivaldo Araújo de Castro, Marcos Alberto Rodrigues Vasconcelos, Airton Natanael Coelho Dias, Ludovic Ferrière, Wolf Uwe Reimold, Ana Maria Góes, Jackson Alves Martins, Liliana Sayuri Osako, Raimundo Mariano Gomes Castelo Branco   +9 more
wiley   +1 more source

A New Rarity Assessment of the “Disk of Satellites”: The Milky Way System Is the Exception Rather Than the Rule in the ΛCDM Cosmology

The Astrophysical Journal
The majority of satellite galaxies around the Milky Way (MW) show disk-like distributions (the disk of satellites; DoS), which is a small-scale problem of the lambda cold dark matter cosmology.
Chanoul Seo, Suk-Jin Yoon, Sanjaya Paudel, Sung-Ho An, Jun-Sung Moon   +4 more
doaj   +1 more source

Scale Invariant Density Perturbations from Cyclic Cosmology

, 2015
It is shown how quantum fluctuations of the radiation during the contraction era of a CBE (Comes Back Empty) cyclic cosmology can provide density fluctuations which re-enter the horizon during the subsequent expansion era and at lowest order are scale ...
Frampton, Paul Howard
core   +1 more source

Local and Global Flatness in Cosmology

Journal of Modern Physics, 2019
We raise the question of how the curvature parameter k is related to the curvature of the universe. We also show that, for a cosmological model that can be interpreted geometrically as a pseudo-hypersphere with a time-dependent radius, the Einstein field equations are not sufficient to fully describe the model.
openaire   +2 more sources

Anhydrous minerals in asteroid Bennu: Evidence for well‐preserved primordial components

Meteoritics &Planetary Science, EarlyView.
Abstract Aqueously altered carbonaceous astromaterials are dominated by secondary minerals, but a minor fraction of primary, anhydrous silicates and oxides escape alteration, offering insight into the original composition of asteroid parent bodies. We report the mineralogy, petrology, mineral chemistry, and oxygen isotopes of anhydrous minerals—50 ...
S. S. Russell, I. A. Franchi, T. Salge, X. Zhao, R. H. Jones, A. J. King, N. V. Almeida, P. F. Schofield, H. C. Bates, E. A. Cortes‐Calderon, N. Kawasaki, Y. Yurimoto, Y. Marrocchi, G. Libourel, K. Thomas‐Keprta, L. P. Keller, K. Righter, T. J. McCoy, T. J. Zega, J. J. Barnes, A. N. Nguyen, S. Tachibana, H. C. Connolly Jr, D. S. Lauretta   +23 more
wiley   +1 more source

Temperature Scaling in Flat Space Cosmology in Comparison to Standard Cosmology

Journal of Modern Physics, 2018
Flat Space Cosmology (FSC) is a mathematical model of universal expansion which has proven to be remarkably accurate in comparison to observations. Temperature scaling is redefined in this paper in terms of a new “Universal Temperature” Tu scale according to Tu = T 2, where T 2 is in K2.
Eugene Terry Tatum, U. V. S. Seshavatharam   +1 more
openaire   +2 more sources

Geophysical investigation of the Santa Marta impact structure—Piauí State, Brazil

Meteoritics &Planetary Science, EarlyView.
Abstract The Santa Marta impact structure in northeastern Brazil, recognized as a partially preserved complex crater, was investigated through an integrated geophysical study employing magnetotelluric (MT) and gravity methods. Our research provides constraints on the crater's subsurface architecture.
Elienara Vasconcelos, João De Oliveira, Marcos Vasconcelos, Martyn Unsworth, Andrea Santos‐Matos, Florivaldo Sena   +5 more
wiley   +1 more source

Araguainha Dome, Brazil: A polygonal impact structure due to a complex pre‐impact regional structural framework

Meteoritics &Planetary Science, EarlyView.
Abstract We investigated the structural framework of the north–northwestern Paraná Basin in Brazil to test whether the pre‐impact structures in this region may have had any influence on the first‐order formation and morphostructure of the Araguainha impact structure (AIS).
Renato B. Bernardes, Wolf U. Reimold, Roger L. Gibson, Julia B. Curto Ma, Adolfo B. Silva, Natalia Hauser   +5 more
wiley   +1 more source

Revisiting the Hummeln structure, Sweden—A shallow marine Cambrian impact structure

Meteoritics &Planetary Science, EarlyView.
Abstract Hummeln is a simple impact structure located in south‐eastern Sweden. It is approximately 1.2 km in diameter and almost completely covered by a lake. Here, we present the first detailed investigation of impactites and mapping of the 164.25 m deep drill core Hummeln‐1 with a focus on impact metamorphism and the impact process.
S. Alwmark, J. Granbom, P. Ahlberg, M. Calner, S. Richoz, K. J. Gajewska, W. R. Hyde, K. Ljung, C. Alwmark   +8 more
wiley   +1 more source

Potential of VIS‐IR imaging spectroscopy and SEM‐EDS and EMPA to map the mineralogical composition of NWA 7317 (CR6)

Meteoritics &Planetary Science, EarlyView.
Abstract Asteroid compositional analysis relies on comparing reflectance spectra with laboratory data from well‐characterized meteorites. To advance this comparison, we performed a comprehensive laboratory analysis on a slab of the Northwest Africa (NWA) 7317—CR6 carbonaceous chondrite.
Simone Pascucci, Tiberio Cuppone, Martina Casalini, Simone De Angelis, Antonio Lettino, Angelo Palombo, Eliana La Francesca, Gianrico Filacchione, Maria Cristina De Sanctis, Anna Galiano, Giovanni Pratesi   +10 more
wiley   +1 more source