Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userReorientation of Sputnik Planitia implies a Subsurface Ocean on Pluto
97
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The deep nitrogen-covered Sputnik Planitia (SP; informal name) basin on Pluto is located very close to the longitude of Plutos tidal axis[1] and may be an impact feature [2], by analogy with other large basins in the solar system[3,4]. Reorientation[5-7] due to tidal and rotational torques can explain SPs location, but requires it to be a positive gravity anomaly[7], despite its negative topography. Here we argue that if SP formed via impact and if Pluto possesses a subsurface ocean, a positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest N2 deposition. Without a subsurface ocean a positive gravity anomaly requires an implausibly thick N2 layer (greater than 40 km). A rigid, conductive ice shell is required to prolong such an oceans lifetime to the present day[8] and maintain ocean uplift. Because N2 deposition is latitude-dependent[9], nitrogen loading and reorientation may have exhibited complex feedbacks[7].
rate research
Read More
Sputnik Planitia, Plutos gigantic ice glacier, hosts numerous scientific mysteries, including the presence of thousands of elongated pit structures. We examine various attributes of these pit structures in New Horizons data sets, revealing their length, aspect ratios, and orientation properties; we also study their interior reflectivities, colors, and compositions, and compare these attributes to some other relevant regions on Pluto. We then comment on origin mechanisms of the pits and also the fate of the missing volatiles represented by the pits on Sputnik Planitia.
Data from the New Horizons mission to Pluto show no craters on Sputnik Planum down to the detection limit (2 km for low resolution data, 625 m for high resolution data). The number of small Kuiper Belt Objects that should be impacting Pluto is known to some degree from various astronomical surveys. We combine these geological and telescopic observations to make an order of magnitude estimate that the surface age of Sputnik Planum must be less than 10 million years. This maximum surface age is surprisingly young and implies that this area of Pluto must be undergoing active resurfacing, presumably through some cryo-geophysical process. We discuss three possible resurfacing mechanisms and the implications of each one for Plutos physical properties.
The goal of this chapter is to review hypotheses for the origin of the Pluto system in light of observational constraints that have been considerably refined over the 85-year interval between the discovery of Pluto and its exploration by spacecraft. We focus on the giant impact hypothesis currently understood as the likeliest origin for the Pluto-Charon binary, and devote particular attention to new models of planet formation and migration in the outer solar system. We discuss the origins conundrum posed by the systems four small moons. We also elaborate on the implications of these scenarios for the dynamical environment of the early transneptunian disk, the likelihood of finding a Pluto collisional family, and the origin of other binary systems in the Kuiper belt. Finally, we highlight outstanding open issues regarding the origins of the Pluto system and suggest areas of future progress.
A search for temporal changes on Pluto and Charon was motivated by (1) the discovery of young surfaces in the Pluto system that imply ongoing or recent geologic activity, (2) the detection of active plumes on Triton during the Voyager 2 flyby, and (3) the abundant and detailed information that observing geologic processes in action provides about the processes. A thorough search for temporal changes using New Horizons images was completed. Images that covered the same region were blinked and manually inspected for any differences in appearance. The search included full-disk images such that all illuminated regions of both bodies were investigated and higher resolution images such that parts of the encounter hemispheres were investigated at finer spatial scales. Changes of appearance between different images were observed but in all cases were attributed to variability of the imaging parameters (especially geometry) or artifacts. No differences of appearance that are strongly indicative of a temporal change were found on the surface or in the atmosphere of either Pluto or Charon. Limits on temporal changes as a function of spatial scale and temporal interval during the New Horizons encounter are determined. The longest time interval constraint is one Pluto/Charon rotation period (~6.4 Earth days). Contrast reversal and high-phase bright features that change in appearance with solar phase angle are identified. The change of appearance of these features is most likely due to the change in phase angle rather than a temporal change. Had active plumes analogous to the plumes discovered on Triton been present on the encounter hemispheres of either Pluto or Charon, they would have been detected. The absence of active plumes may be due to temporal variability (i.e., plumes do occur but none were active on the encounter hemispheres during the epoch of the New Horizons encounter ...
The ice-rich dwarf planet Ceres is the largest object in the main asteroid belt and is thought to have a brine or mud layer at a depth of tens of kilometers. Furthermore, recent surface deposits of brine-sourced material imply shallow feeder structures such as sills or dikes. Inductive sounding of Ceres can be performed using the solar wind as a source, as was done for the Moon during Apollo. However, the magnetotelluric method -- measuring both electric and magnetic fields at the surface -- is not sensitive to plasma effects that were experienced for Apollo, which used an orbit-to-surface magnetic transfer function. The highly conductive brine targets are readily separable from the resistive ice and rock interior, such that the depth to deep and shallow brines can be assessed simultaneously. The instrumentation will be tested on the Moon in 2023 and is ready for implementation on a Ceres landed mission.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
