Water ice is thought to be trapped in large permanently shadowed regions (PSRs) in the Moon's polar regions, due to their extremely low temperatures. Here, we show that many unmapped cold traps exist on small spatial scales, substantially augmenting the areas where ice may accumulate. Using theoretical models and data from the Lunar Reconnaissance Orbiter, we estimate the contribution of shadows on scales from 1 km down to 1 cm, the smallest distance over which we find cold-trapping to be effective for water ice. Approximately 10-20\%
Ice in such cold traps can be harvested with relative ease.
Swaczyna used SWAP’s measurements to derive the density of neutral hydrogen at the termination shock, where the solar wind butts up against the interstellar medium and abruptly slows down. After months of careful checks and tests, the number they found was 0.127 particles per cubic centimeter, or about 120 hydrogen atoms in a space the size of a quart of milk.
We show that an equal-mass, temporary binary companion to the Sun in the solar birth cluster at a separation of ~103 au would have increased the likelihood of forming the observed population of outer Oort Cloud objects and of capturing Planet Nine. In particular, the discovery of a captured origin for Planet Nine would favor our binary model by an order of magnitude relative to a lone stellar history. Our model predicts an overabundance of dwarf planets, discoverable by Legacy Survey of Space and Time, with similar orbits to Planet Nine, which would result from capture by the stellar binary.
The hypothesized existence of planet 9 is explained well if the early solar system was a binary star system.
Recent analyses have shown that distant orbits within the scattered diskpopulation of the Kuiper belt exhibit an unexpected clustering in theirrespective arguments of perihelion. While several hypotheses have been putforward to explain this alignment, to date, a theoretical model that cansuccessfully account for the observations remains elusive. In this work we showthat the orbits of distant Kuiper belt objects cluster not only in argument ofperihelion, but also in physical space. We demonstrate that the perihelionpositions and orbital planes of the objects are tightly confined and that sucha clustering has only a probability of 0.007% to be due to chance, thusrequiring a dynamical origin. We find that the observed orbital alignment canbe maintained by a distant eccentric planet with mass greater than ~10 Earthmasses, whose orbit lies in approximately the same plane as those of thedistant Kuiper belt objects, but whose perihelion is 180 degrees away from theperihelia of the minor bodies. In addition to accounting for the observedorbital alignment, the existence of such a planet naturally explains thepresence of high perihelion Sedna-like objects, as well as the known collectionof high semimajor axis objects with inclinations between 60 and 150 degreeswhose origin was previously unclear. Continued analysis of both distant andhighly inclined outer solar system objects provides the opportunity for testingour hypothesis as well as further constraining the orbital elements and mass ofthe distant planet.