Results 71 to 80 of about 1,003,872 (220)

The Great Cosmic Silence: What Does the Fermi Paradox Tell About the Future of Humanity?

Global Policy, Volume 17, Issue 4, Page 553-565, September 2026.
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

Towards a Measurement of the Primordial Helium Isotope Ratio

The Astrophysical Journal
We report the discovery of two metastable neutral helium (He I *) absorbers in the Milky Way, and use the upgraded CRyogenic InfraRed Echelle Spectrograph (or CRIRES) on the Very Large Telescope to determine the helium isotope ratio, ^3 He/ ^4 He, along ...
Ryan J. Cooke, James W. Johnson, Pasquier Noterdaeme, Max Pettini, Louise Welsh, Aldric Wong, Céline Péroux   +6 more
doaj   +1 more source

Spaceborne and spaceborn: Physiological aspects of pregnancy and birth during interplanetary flight

Experimental Physiology, Volume 111, Issue 9, Page 4015-4040, 1 September 2026.
Abstract Crewed interplanetary return missions that are on the planning horizon will take years, more than enough time for initiation and completion of a pregnancy. Pregnancy is viewed as a sequence of processes – fertilization, blastocyst formation, implantation, gastrulation, placentation, organogenesis, gross morphogenesis, birth and neonatal ...
Arun V. Holden
wiley   +1 more source

Regarding the Detection of Interstellar C4 and C5 Molecules

The Astrophysical Journal
Analysis of very high signal-to-noise ratio (S/N) spectra of reddened stars allowed us to determine an upper limit (UL) of the column density N (C _4 ).
G. A. Galazutdinov, E. I. Kazanina, J. Krełowski   +2 more
doaj   +1 more source

An Instrument for Isomer‐Specific Action Spectroscopy of Charged Clusters: Electronic Spectra of C 14 + and Ca@C 60 +

Chemistry–Methods, Volume 6, Issue 8, August 2026.
Disentangling spectral congestion of a mixture of isomers in gas‐phase spectroscopy is critical. We present an instrument combining ion mobility, mass spectrometry, and spectroscopy in a cryogenic 3D Paul trap to investigate the isomer‐specific charged clusters and illustrate its performance with the electronic spectra of C14+ and Ca@C60+. Interpreting
Corentin Rossi, Anne P. Rasmussen, Zekai Li, Uma Namangalam, Bérenger Gans, Juraj Jašík, Jan Žabka, Hugo Bauduin, Christophe Charrière, Vira Davouloury, Jean‐Philippe Dugal, Jérome Guigand, Catherine Le Bris, Ugo Jacovella   +13 more
wiley   +1 more source

Tiny-scale Properties within the Interstellar Medium toward PSR J1644−4559. I. Observational Evidence of Turbulence-induced Tiny-scale Atomic Structures

The Astrophysical Journal Supplement Series
We investigated H i absorption toward a single pulsar, PSR J1644−4559, and its variability over timescales from days to years, using Murriyang, CSIRO’s Parkes Radio Telescope.
Mengting Liu, Di Li, J. R. Dawson, Joel M. Weisberg, Snežana Stanimirović, George Hobbs, Simon Johnston, Lawrence Toomey, Siyao Xu, Chao-Wei Tsai, Donghui Quan, Stacy Mader, James A. Green, Lei Zhang, Ningyu Tang, Pei Wang, Kai Zhang, Pei Zuo, Gan Luo, Yi Feng, Shi Dai, Aditi Kaushik, Mengyao Xue, Chenchen Miao   +23 more
doaj   +1 more source

Variations of Interstellar Ultra-Violet Absorption [PDF]

Symposium - International Astronomical Union, 1973
It is shown that mixtures of graphite core-ice mantle grains with large and small mean size and graphite grains provide good fits to the observed interstellar extinction curve.
openaire   +1 more source

Latitude Survey of Neutrons and Muons to Determine Cosmic Ray Neutron Sensing Yield Functions

Journal of Geophysical Research: Space Physics, Volume 131, Issue 8, August 2026.
Abstract Cosmic Ray Neutron Sensing (CRNS) is a ground‐based technique that utilizes epithermal neutron measurements as a proxy for environmental hydrogen content. Similarly to other ground‐based cosmic ray detectors (e.g., neutron monitors), CRNS detectors are affected by the solar cycle and space weather events.
Lasse Hertle, Fraser Baird, Ulrich Schmidt, Bernd Heber, Michael Walter, Nora Krebs, Paul Schattan, Pauli Väisänen, Peter Dietrich, Steffen Zacharias, Solveig Landmark, Daniel Rasche, Marco Kossatz, Gary Womack, Steve Hamann, Enrico Gazzola, Martin Schrön   +16 more
wiley   +1 more source

An Ultraviolet Study of CO Chemistry in the Magellanic Clouds

The Astronomical Journal
How does molecular cloud chemistry change with metallicity? In this work, we study the relation between molecular hydrogen (H _2 ) and carbon monoxide (CO) at 1/2 and 1/5 solar metallicity using ultraviolet absorption spectroscopy obtained as part of the
Kirill Tchernyshyov, Jessica K. Werk, Julia Roman-Duval   +2 more
doaj   +1 more source

Near‐Earth Cosmic Ray Modulation Index ϕ and Neutron Monitor Cutoff Rigidities at Hourly Cadence: Toward an Improved Monitoring of Solar‐Terrestrial Radiation Environment, Space Weather, and Space Climate

Journal of Geophysical Research: Space Physics, Volume 131, Issue 8, August 2026.
Abstract Cosmic rays (CRs) are energetic particles originating from galactic and extragalactic sources. When arriving into the solar system and the Sun's heliosphere, they are diverted and modulated by the magnetic activity of the Sun. This modulation can be quantified by the modulation parameter ϕ $\phi $ determined with the Force‐field approximation (
Pauli Väisänen, Nicholas Larsen, Sergey Koldobskiy, Markus Similä, David Pelosi, Miguel Orcinha   +5 more
wiley   +1 more source