Preprints
Filtering by Subject: The Sun and the Solar System
Al Hawi, a 4-km-wide impact structure in northern Saudi Arabia
Published: 2024-09-23
Subjects: Astrophysics and Astronomy, Earth Sciences, Geology, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Planetary Geology, Planetary Sciences, The Sun and the Solar System
The northern region of Saudi Arabia hosts several impact craters and structures. This paper describes the discovery of a 4-km-wide complex impact structure located in the paleozoic sedimentary rocks of northern Saudi Arabia 210 kilometers north east of the city of Tabuk. The impact structure is composed of a central peak displaying intense folding and shock metamorphism surrounded by an inner [...]
Orbital, the Box - An interactive educational tool for in-depth understanding of astronomical climate forcing.
Published: 2021-04-07
Subjects: Adult and Continuing Education, Astrophysics and Astronomy, Climate, Earth Sciences, Education, Educational Methods, Geology, Geophysics and Seismology, Higher Education, Instructional Media Design, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, The Sun and the Solar System
“Orbital, the Box” provides an interactive tool with graphical user interface (GUI) for stimulating active, visual learning for understanding of astronomical climate forcing. This cross-platform tool can be run locally on a personal computer using a standard web browser environment with no need for plugins, thus maximising accessibility for students and teachers alike. The tool facilitates in the [...]
Habitability of the early Earth: Liquid water under a faint young Sun facilitated by strong tidal heating due to a nearby Moon
Published: 2020-07-10
Subjects: Astrophysics and Astronomy, Earth Sciences, Other Astrophysics and Astronomy, Other Earth Sciences, Physical Sciences and Mathematics, Planetary Sciences, The Sun and the Solar System
Geological evidence suggests liquid water near the Earths surface as early as 4.4 gigayears ago when the faint young Sun only radiated about 70 % of its modern power output. At this point, the Earth should have been a global snowball. An extreme atmospheric greenhouse effect, an initially more massive Sun, release of heat acquired during the accretion process of protoplanetary material, and [...]
Detection of VLF attenuation in the Earth-ionosphere waveguide caused by X-class solar flares using a global lightning location network
Published: 2020-01-09
Subjects: Astrophysics and Astronomy, Earth Sciences, Geophysics and Seismology, Other Physics, Physical Sciences and Mathematics, Physics, The Sun and the Solar System
Solar flares, energetic particles and Earth-impacting coronal mass ejections enhance ionization in the lower ionosphere, inhibiting radio wave propagation in the Earth-ionosphere waveguide (EIWG). This enhanced ionization is observed locally by ionosondes and GPS/GNSS receivers, but spatial coverage of these observations is limited by receiver location. VLF propagation studies have previously [...]
Decomposition of Amino Acids in Water with Application to In-Situ Measurements of Enceladus, Europa and Other Hydrothermally Active Icy Ocean Worlds
Published: 2019-04-17
Subjects: Astrophysics and Astronomy, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Sciences, The Sun and the Solar System
To test the potential of using amino acid abundances as a biosignature at icy ocean worlds, we investigate whether primordial amino acids (accreted or formed by early aqueous processes) could persist until the present time. By examining the decomposition kinetics of amino acids in aqueous solution based on existing laboratory rate data, we find that all fourteen proteinogenic amino acids [...]
Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars
Published: 2019-01-01
Subjects: Astrophysics and Astronomy, Earth Sciences, Geology, Physical Sciences and Mathematics, The Sun and the Solar System
Lakes existed on Mars later than 3.6 billion years ago, according to sedimentary evidence for deltaic deposition. The observed fluvio-lacustrine deposits suggest that individual lake-forming climates persisted for at least several thousand years (assuming dilute flow). But the lake watersheds’ little weathered soils indicate a largely dry climate history, with intermittent runoff events. Here we [...]
Persistent or repeated surface habitability on Mars during the Late Hesperian - Amazonian
Published: 2019-01-01
Subjects: Astrophysics and Astronomy, Earth Sciences, Geology, Physical Sciences and Mathematics, The Sun and the Solar System
Large alluvial fan deposits on Mars record relatively recent habitable surface conditions (≲3.5 Ga, Late Hesperian – Amazonian). We find net sedimentation rate <(4-8) μm/yr in the alluvial-fan deposits, using the frequency of craters that are interbedded with alluvial fan deposits as a fluvial-process chronometer. Considering only the observed interbedded craters sets a lower bound of >20 [...]
Stratigraphy of Aeolis Dorsa, Mars: stratigraphic context of the great river deposits
Published: 2018-04-03
Subjects: Astrophysics and Astronomy, Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics, The Sun and the Solar System
Unraveling the stratigraphic record is the key to understanding ancient climate and past climate changes on Mars (Grotzinger et al. 2011). Stratigraphic records of river deposits hold particular promise because rain or snowmelt must exceed infiltration plus evaporation to allow sediment transport by rivers. Therefore, river deposits when placed in stratigraphic order could constrain the number, [...]