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Topic Review
Mapping Imaging Spectrometer for Europa
The Mapping Imaging Spectrometer for Europa (MISE) is an imaging near infrared spectrometer on board the Europa Clipper mission to Jupiter's moon Europa. MISE will examine Europa's surface composition and relate it to the habitability of its internal water ocean.
  • 289
  • 01 Dec 2022
Topic Review
Conceptual Programs in Physics
Different subfields of physics have different programs for determining the state of a physical system.
  • 289
  • 18 Oct 2022
Topic Review
Cepheus
Cepheus is a northern constellation named after the mythical king of Aethiopia in Greek mythology. Positioned in the celestial northern hemisphere, it is recognizable for its distinctive shape resembling a house with a peaked roof. Cepheus is home to several notable deep-sky objects, including the famous variable star Delta Cephei, which gave its name to a class of pulsating stars known as Cepheid variables.
  • 288
  • 29 Feb 2024
Topic Review
Heliophysics NASA Science
Heliophysics is an aspect of NASA science that enables understanding the Sun, heliosphere, and planetary environments as a single connected system. In addition to solar processes, this domain of study includes the interaction of solar plasma and solar radiation with Earth, the other planets, and the galaxy. By analyzing the connections between the Sun, solar wind, and planetary space environments, the fundamental physical processes that occur throughout the universe are uncovered. Understanding the connections between the Sun and its planets will allow for predicting the impacts of solar interaction on humans, technological systems, and even the presence of life itself. This is also the stated goal of Science Mission Directorate's Heliophysics Research.
  • 288
  • 25 Oct 2022
Topic Review
Nuclear Physics Opportunities at European Small-Scale Facilities
Small-scale facilities play a significant role in the landscape of nuclear physics research in Europe. They address a wide range of fundamental questions and are essential for teaching and training personnel in accelerator technology and science, providing them with diverse skill sets, complementary to large projects.  The current status, available instrumentation, as well as perspectives of nuclear physics research at small-scale facilities are given. To obtain a complete overview, a few medium-scale facilities—the INFN Laboratori Nazionali del Sud, IJC Lab, and the Jyväskylä Accelerator Laboratory—are also described.
  • 287
  • 18 Jan 2024
Topic Review
Phase Transitions in Boron Carbide
Phase transitions known to date have been identified due to significant changes of properties. The phase transition near the chemical composition B8C by clear change of the electronic structure. The endothermic temperature-dependent phase transition at 712 K according to the change of specific heat. The high-pressure phase transition at 33.2 GPa by the drastic change of optical appearance from opacity to transparency. These phase transitions affect IR- and Raman-active phonons and other solid-state properties. The phase transitions at B~8C and 712 K mean that a well-defined distorted structure is converted into another one. In the high-pressure phase transition, an apparently well-defined distorted structure changes into a highly ordered one. In all these cases, the distribution of polar C atoms in the icosahedra plays a crucial role.
  • 286
  • 27 Oct 2023
Topic Review
List of Unnumbered Minor Planets: 2002 R–S
This is a partial list of unnumbered minor planets for principal designations assigned between 1 September 2002 and 31 September 2002 (R–S).
  • 285
  • 14 Nov 2022
Topic Review
Osmium-182
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 284
  • 21 Nov 2022
Topic Review
Physicist and Christian
Physicist and Christian: A Dialogue Between the Communities (1961) is a book by William G. Pollard. Much of the attention given to the book such as its review in Time (magazine) magazine has been attributed to the fact that Pollard was not only a well-respected physicist but also an Anglican priest. The book deliberately avoids specific subject matter differences, focusing on religion and science both as human communities. An important theme is the idea that human knowledge—scientific or religious—can be developed only by those, like Pollard, who have "fully and freely" given themselves to a human community, whether to the physics community or Christian community or some other, e.g., the United States Marine Corps. Also an important theme is Pollard's argument and cautions against a cultural norm in which scientific knowledge would be objective and public, on the one hand, while religious knowledge would be subjective and private, on the other.
  • 283
  • 15 Nov 2022
Topic Review
Mathematical and Logical Realism
According to Balaguer, only two views of the metaphysics of mathematics manage to adequately answer all objections: these are Platonic set theory (as a form of realism) and fictionalism (as a form of anti-realism). Balaguer takes a relatively reserved stance towards the dilemma that one of these two perspectives is correct through three epistemic conclusions: (a) there is no reason to believe or not believe in abstract mathematical objects, (b) it can never in principle have a reason to believe or not believe in abstract mathematical objects, or (c) there is no material fact that could determine between Platonic set theory and fictionalism, although both adequately answer all objections (except, in a way, the question of proving the existence of abstract mathematical objects). The first key question that divides the metaphysics of mathematics into two domains, is the question of whether mathematical theories represent truthful descriptions of some real part of the world. Realistic theories answer affirmatively, while anti-realistic theories answer negatively, claiming that mathematics has no ontology, or that its concepts are objectively empty. The question further divides the realist camp into two groups and is “are mathematical objects spatiotemporal?”. Platonic set theory answers negatively, while anti-Platonism answers affirmatively. The question further divides anti-Platonism into psychologism and physicalism and reads: “what is the nature of mathematical spatiotemporal objects?”. According to psychologism, the objects in question are mental objects, or mathematical statements represent truthful descriptions of mental objects, while according to physicalism, the subject of mathematical statements is non-mental parts of physical reality.
  • 283
  • 17 Nov 2023
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