A Postulated Planetary Collision, the Terrestrial Planets, the Moon and Smaller Solar-System Bodies

2013 ◽  
Vol 111 (1-2) ◽  
pp. 1-14 ◽  
Author(s):  
M. M. Woolfson
Author(s):  
Karel Schrijver

In this chapter, the author summarizes the properties of the Solar System, and how these were uncovered. Over centuries, the arrangement and properties of the Solar System were determined. The distinctions between the terrestrial planets, the gas and ice giants, and their various moons are discussed. Whereas humans have walked only on the Moon, probes have visited all the planets and several moons, asteroids, and comets; samples have been returned to Earth only from our moon, a comet, and from interplanetary dust. For Earth and Moon, seismographs probed their interior, whereas for other planets insights come from spacecraft and meteorites. We learned that elements separated between planet cores and mantels because larger bodies in the Solar System were once liquid, and many still are. How water ended up where it is presents a complex puzzle. Will the characteristics of our Solar System hold true for planetary systems in general?


2014 ◽  
Vol 9 (S310) ◽  
pp. 194-203 ◽  
Author(s):  
Sean N. Raymond ◽  
Alessandro Morbidelli

AbstractThe “Grand Tack” model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or “tack” point was at ~ 1.5 AU the inner disk of terrestrial building blocks would have been truncated at ~ 1 AU, naturally producing the terrestrial planets' masses and spacing. During the gas giants' migration the asteroid belt is severely depleted but repopulated by distinct planetesimal reservoirs that can be associated with the present-day S and C types. The giant planets' orbits are consistent with the later evolution of the outer Solar System.Here we confront common criticisms of the Grand Tack model. We show that some uncertainties remain regarding the Tack mechanism itself; the most critical unknown is the timing and rate of gas accretion onto Saturn and Jupiter. Current isotopic and compositional measurements of Solar System bodies – including the D/H ratios of Saturn's satellites – do not refute the model. We discuss how alternate models for the formation of the terrestrial planets each suffer from an internal inconsistency and/or place a strong and very specific requirement on the properties of the protoplanetary disk.We conclude that the Grand Tack model remains viable and consistent with our current understanding of planet formation. Nonetheless, we encourage additional tests of the Grand Tack as well as the construction of alternate models.


1989 ◽  
Vol 53 (370) ◽  
pp. 135-151 ◽  
Author(s):  
Roger G. Burns

AbstractSpectral measurements of sunlight reflected from planetary surfaces, when correlated with experimental visible-near-infrared spectra of rock-forming minerals, are being used to detect transition metal cations, to identify constituent minerals, and to determine modal mineralogies of regoliths on terrestrial planets. Such remote-sensed reflectance spectra measured through earth-based telescopes may have absorption bands in the one micron and two micron wavelength regions which originate from crystal field transitions within Fe2+ ions. Pyroxenes with Fe2+ in M2 positions dominate the spectra, and the resulting 1 μm versus 2 µm spectral determinative curve is used to identify compositions and structure-types of pyroxenes on surfaces of the Moon, Mercury, and asteroids, after correcting for experimentally-determined temperature-shifts of peak positions. Olivines and Fe2+-bearing plagioclase feldspars also give diagnostic peaks in the 1 µm region, while tetrahedral Fe2+ in glasses absorb in the 2 µm region as well. Opaque ilmenite, spinel and metallic iron phases mask all of these Fe2+ spectral features. Laboratory studies of mixed-mineral assemblages enable coexisting Fe2+ phases to be identified in remote-sensed reflectance spectra of regoliths. Thus, noritic rocks in the lunar highlands, troctolites in central peaks of impact craters such as Copernicus, and high-Ti and low-Ti mare basalts have been mapped on the Moon's surface by telescopic reflectance spectroscopy. The Venusian atmosphere prevents remote-sensed spectral measurements of its surface mineralogy, while atmospheric CO2 and ferric-bearing materials in the regolith on Mars interfere with pyroxene characterization in bright- and dark-region spectra. Reflectance spectral measurements of several meteorite types, including specimens from Antarctica, are consistent with a lunar highland origin for achondrite ALHA 81005 and a martian origin for shergottite EETA 79001, although source regions may not be outermost surfaces of the Moon and Mars. Correlations with asteroid reflectance spectra suggest that Vesta is the source of basaltic achondrites, while wide ranges of olivine/pyroxene ratios are inconsistent with an ordinary-chondrite surface composition of many asteroids. Visible-near-infrared spectrometers are destined for instrument payloads in future spacecraft missions to neighbouring solar system bodies.


2020 ◽  
Vol 643 ◽  
pp. A146
Author(s):  
J. I. González Hernández ◽  
R. Rebolo ◽  
L. Pasquini ◽  
G. Lo Curto ◽  
P. Molaro ◽  
...  

Context. The general theory of relativity predicts the redshift of spectral lines in the solar photosphere as a consequence of the gravitational potential of the Sun. This effect can be measured from a solar disk-integrated flux spectrum of the Sun’s reflected light on Solar System bodies. Aims. The laser frequency comb (LFC) calibration system attached to the HARPS spectrograph offers the possibility of performing an accurate measurement of the solar gravitational redshift (GRS) by observing the Moon or other Solar System bodies. Here, we analyse the line shift observed in Fe absorption lines from five high-quality HARPS-LFC spectra of the Moon. Methods. We selected an initial sample of 326 photospheric Fe lines in the spectral range between 476–585 nm and measured their line positions and equivalent widths (EWs). Accurate line shifts were derived from the wavelength position of the core of the lines compared with the laboratory wavelengths of Fe lines. We also used a CO5BOLD 3D hydrodynamical model atmosphere of the Sun to compute 3D synthetic line profiles of a subsample of about 200 spectral Fe lines centred at their laboratory wavelengths. We fit the observed relatively weak spectral Fe lines (with EW< 180 mÅ) with the 3D synthetic profiles. Results. Convective motions in the solar photosphere do not affect the line cores of Fe lines stronger than about ∼150 mÅ. In our sample, only 15 Fe I lines have EWs in the range 150< EW(mÅ) < 550, providing a measurement of the solar GRS at 639 ± 14 m s−1, which is consistent with the expected theoretical value on Earth of ∼633.1 m s−1. A final sample of about 97 weak Fe lines with EW < 180 mÅ allows us to derive a mean global line shift of 638 ± 6 m s−1, which is in agreement with the theoretical solar GRS. Conclusions. These are the most accurate measurements of the solar GRS obtained thus far. Ultrastable spectrographs calibrated with the LFC over a larger spectral range, such as HARPS or ESPRESSO, together with a further improvement on the laboratory wavelengths, could provide a more robust measurement of the solar GRS and further testing of 3D hydrodynamical models.


1997 ◽  
Vol 23 (1) ◽  
pp. 263-274

At the 1988 Baltimore General Assembly of the International Astronomical Union, members of several Commissions dealing with planetary science expressed deep concern that no work was being undertaken to identify and avoid pollution problems in interplanetary space beyond the Moon. At that time NASA had convened a conference on problems in cislunar space due to the large and growing numbers of orbiting fragments hazardous to space vehicles. In translunar space this is hardly a problem. However an alarming number of future interplanetary mission proposals were considered for other reasons to be potentially harmful to various solar system bodies and interplanetary space itself.


2021 ◽  
Vol 217 (5) ◽  
Author(s):  
Cesare Grava ◽  
Rosemary M. Killen ◽  
Mehdi Benna ◽  
Alexey A. Berezhnoy ◽  
Jasper S. Halekas ◽  
...  

AbstractVolatiles and refractories represent the two end-members in the volatility range of species in any surface-bounded exosphere. Volatiles include elements that do not interact strongly with the surface, such as neon (detected on the Moon) and helium (detected both on the Moon and at Mercury), but also argon, a noble gas (detected on the Moon) that surprisingly adsorbs at the cold lunar nighttime surface. Refractories include species such as calcium, magnesium, iron, and aluminum, all of which have very strong bonds with the lunar surface and thus need energetic processes to be ejected into the exosphere. Here we focus on the properties of species that have been detected in the exospheres of inner Solar System bodies, specifically the Moon and Mercury, and how they provide important information to understand source and loss processes of these exospheres, as well as their dependence on variations in external drivers.


1992 ◽  
Vol 9 ◽  
pp. 508-536
Author(s):  
B. Kolaczek

Solar System bodies are different. They have different sizes, from large planets to small asteroids, and shapes. They have different structure, from solid body to solid body with fluid atmosphere or core, to gaseous bodies, but all of them rotate. The Solar System is a big laboratory for studying rotation of solid and fluid bodies.Different observational methods are applied to determine the rotation of the Solar system bodies. They depend on the position of the observer and on the structure of the bodies. The most accurate methods, laser ranging to the Moon and artificial satellites and Very Long Base radio Interferometry have been applied to the determination of the rotation of the Earth and the Moon. Their accuracy is better than 0.001”, which on the surface of the Earth corresponds to about 3 cm. Radiotracking of artifical satellites have been used for Earth, Moon, Venus, Mars. In the case of Jupiter, Saturn, Uranus, Neptune and Pluto-Charon magnetic and photometric observations have been used respectively. Their accuracy is of the order of one tenth of a degree.


Icarus ◽  
2015 ◽  
Vol 248 ◽  
pp. 89-108 ◽  
Author(s):  
D.C. Rubie ◽  
S.A. Jacobson ◽  
A. Morbidelli ◽  
D.P. O’Brien ◽  
E.D. Young ◽  
...  

2021 ◽  
Vol 217 (4) ◽  
Author(s):  
Diego Janches ◽  
Alexey A. Berezhnoy ◽  
Apostolos A. Christou ◽  
Gabriele Cremonese ◽  
Takayuki Hirai ◽  
...  

AbstractThis manuscript represents a review on progress made over the past decade concerning our understanding of meteoroid bombardment on airless solar system bodies as one of the sources of the formation of their exospheres. Specifically, observations at Mercury by MESSENGER and at the Moon by LADEE, together with progress made in dynamical models of the meteoroid environment in the inner solar system, offer new tools to explore in detail the physical phenomena involved in this complex relationship. This progress is timely given the expected results during the next decade that will be provided by new missions such as DESTINY+, BepiColombo, the Artemis program or the Lunar Gateway.


2007 ◽  
Vol 42 (1) ◽  
pp. 59-70 ◽  
Author(s):  
G. Eroshkin ◽  
V. Pashkevich

Geodetic Rotation of the Solar System Bodies The problem of the geodetic (relativistic) rotation of the major planets, the Moon, and the Sun is studied by using DE404/LE404 ephemeris. For each body the files of the ecliptical components of the vectors of the angular velocity of the geodetic rotation are determined over the time span from AD1000 to AD3000 with one day spacing. The most essential terms of the geodetic rotation are found by means of the least squares method and spectral analysis methods.


Sign in / Sign up

Export Citation Format

Share Document