Exploring the Solar System

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Planetary Systems ◽  
Interplanetary Dust ◽  
Terrestrial Planets ◽  
The Moon ◽  
System P ◽  
Asteroids And Comets

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?

scholarly journals Bayesian constraints on the origin and geology of exo-planetary material using a population of externally polluted white dwarfs

2021 ◽  
Author(s):  
John H D Harrison ◽  
Amy Bonsor ◽  
Mihkel Kama ◽  
Andrew M Buchan ◽  
Simon Blouin ◽  
...  
Keyword(s):  
Solar System ◽  
White Dwarf ◽  
Bayesian Model ◽  
Total Mass ◽  
White Dwarfs ◽  
Bulk Composition ◽  
Planetary Systems ◽  
The Moon ◽  
Planetary Bodies ◽  
Nearby Stars

Abstract White dwarfs that have accreted planetary bodies are a powerful probe of the bulk composition of exoplanetary material. In this paper, we present a Bayesian model to explain the abundances observed in the atmospheres of 202 DZ white dwarfs by considering the heating, geochemical differentiation, and collisional processes experienced by the planetary bodies accreted, as well as gravitational sinking. The majority (>60%) of systems are consistent with the accretion of primitive material. We attribute the small spread in refractory abundances observed to a similar spread in the initial planet-forming material, as seen in the compositions of nearby stars. A range in Na abundances in the pollutant material is attributed to a range in formation temperatures from below 1,000 K to higher than 1,400 K, suggesting that pollutant material arrives in white dwarf atmospheres from a variety of radial locations. We also find that Solar System-like differentiation is common place in exo-planetary systems. Extreme siderophile (Fe, Ni or Cr) abundances in 8 systems require the accretion of a core-rich fragment of a larger differentiated body to at least a 3σ significance, whilst one system shows evidence that it accreted a crust-rich fragment. In systems where the abundances suggest that accretion has finished (13/202), the total mass accreted can be calculated. The 13 systems are estimated to have accreted masses ranging from the mass of the Moon to half that of Vesta. Our analysis suggests that accretion continues for 11Myrs on average.

9. Volcanoes beyond Earth

2020 ◽  
pp. 128-142
Author(s):  
Michael J. Branney ◽  
Jan Zalasiewicz
Keyword(s):  
Solar System ◽  
Plate Tectonics ◽  
Planetary Systems ◽  
The Moon ◽  
Mountain Belts ◽  
Tectonic Forces

‘Volcanoes beyond Earth’ highlights volcanoes on other planets. There are many more volcanoes on Venus than there are on Earth, and many remain active. In the absence of plate tectonics and the kind of tectonic forces that raise Earth-style mountain belts, and of streams, rivers, and shorelines, it is volcanism and volcanic products that dominate the surface of this planet. Fossil volcanism occurs in the Moon, Mercury, and Mars; Io, the hypervolcanic moon of Jupiter; and the ice volcanoes of the Solar System. There is potential for volcanism on exoplanets within distant planetary systems.

The role of comets and asteroids in Solar System development: space exploration

1994 ◽  
Vol 349 (1690) ◽  
pp. 323-334 ◽  
Keyword(s):  
Solar System ◽  
System Development ◽  
Space Exploration ◽  
Ground Truth ◽  
Interplanetary Dust ◽  
Calibration Data ◽  
Mixed Classes ◽  
Asteroids And Comets

Exploration by space missions of the near-nucleus regions of comets Halley and Grigg-Skjellerup has resulted in valuable but expensive snapshots of cometary phenomena. The ‘ground truth’ from such missions, which can be established only by this means of dedicated space exploration, provides essential inputs to models of cometary processes. It also gives calibration data for a very wide base of cometary and asteroidal observations, past, present and future. Seen as objects which are both eroded by impacts from interplanetary dust and also the progenitors of interplanetary dust, we find both asteroids and comets are needed to contribute to this population. Contrary to expectations, as new data on the asteroids and comets is analysed, we find the differences between the two classes of primordial body is very much less distinct; accounting for the interplanetary distribution and properties of dust mass requires not only both classes of object but also a distribution of mixed classes. ESA’s newly selected cometary mission Rosetta will offer a unique opportunity, during a rendezvous encounter from aphelion to perihelion, for the extended and detailed in situ observations of a target comet. It will also act as a valuable focus on the nature and role of comets in both the origin and development of the Solar System.

The Origin of the Architecture of the Solar System

2012 ◽  
Vol 20 (2) ◽  
pp. 276-290
Author(s):  
Michael Perryman
Keyword(s):  
Solar System ◽  
Giant Planets ◽  
The Moon ◽  
Central Importance ◽  
Impact Cratering ◽  
Planetary Satellites ◽  
Formation And Evolution ◽  
The Masses ◽  
Modern Astronomy ◽  
Asteroids And Comets

This article relates two topics of central importance in modern astronomy – the discovery some 15 years ago of the first planets around other stars (referred to as exoplanets), and the centuries-old problem of understanding the origin of our own solar system, with its planets, planetary satellites, asteroids, and comets. The surprising diversity of exoplanets, of which more than 500 have already been discovered, has required new models to explain their formation and evolution. In turn, these models explain, rather naturally, a number of important features of our own solar system, amongst them the masses and orbits of the ‘terrestrial’ and ‘gas giant’ planets, the presence and distribution of asteroids and comets, the origin and impact cratering of the Moon, and the existence of water on Earth.

The Outermost Solar System

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
20Th Century ◽  
The Sun ◽  
True Nature ◽  
Separate Family ◽  
System P ◽  
Puzzling Aspect ◽  
Asteroids And Comets

This chapter illustrates how, until the mid-20th century, little was known about the true nature of asteroids and comets. Asteroids looked like single points of light through a telescope, and astronomers tended to think of them as miniature planets, albeit ones with somewhat more elliptical and inclined orbits. Comets seemed to constitute a separate family, distinct from asteroids. They grew much brighter as they approached the Sun, becoming enormously extended objects with a diffuse coma and one or more tails that could extend for millions of kilometers. The most puzzling aspect of comets was how they had managed to survive for the age of the solar system. Comets had such low masses that they could not be measured, yet they shed large amounts of material each time they passed close to the Sun to form their coma and tails.

scholarly journals Crustal porosity reveals the bombardment history of the Moon

2021 ◽  
Author(s):  
Ya Huei Huang ◽  
Jason Soderblom ◽  
David Minton ◽  
Masatoshi Hirabayashi ◽  
Jay Melosh
Keyword(s):  
Solar System ◽  
Surface Expression ◽  
Orbital Evolution ◽  
Terrestrial Planets ◽  
The Moon ◽  
Planetary Evolution ◽  
History Of ◽  
Giant Impacts ◽  
Formation And Evolution ◽  
Lunar Basins

Abstract Planetary bombardment histories provide critical information regarding the formation and evolution of the Solar System and of the planets within it. These records evidence transient instabilities in the Solar System’s orbital evolution, giant impacts such as the Moon-forming impact, and material redistribution. Such records provide insight into planetary evolution, including the deposition of energy, delivery of materials, and crustal processing, specifically the modification of porosity. Bombardment histories are traditionally constrained from the surface expression of impacts — these records, however, are degraded by various geologic processes. Here we show that the Moon’s porosity contains a more complete record of its bombardment history. We find that the terrestrial planets were subject to double the number of ≥20-km-diameter-crater-forming impacts than are recorded on the lunar highlands, fewer than previously thought to have occurred. We show that crustal porosity doesn’t slowly increase as planets evolve, but instead is generated early in a planet’s evolution when most basins formed and decreases as planets evolve. We show that porosity constrains the relative ages of basins formed early in a planet’s evolution, a timeframe for which little information exists. These findings demonstrate that the Solar System was less violent than previously thought. Fewer volatiles and other materials were delivered to the terrestrial planets, consistent with estimates of the delivery of siderophiles and water to the Moon. High crustal porosity early in the terrestrial planets’ evolution slowed their cooling and enhanced their habitability. Several lunar basins formed early than previously considered, casting doubt on the existence of a late heavy bombardment.

Measuring the CosmosParallax and the Transit of Venus

Lightspeed ◽  
2019 ◽  
pp. 27-48
Author(s):  
John C. H. Spence
Keyword(s):  
Solar System ◽  
International Collaboration ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
System P

A review of the methods the ancient Greeks used to measure the distances between the Earth and the Sun, and the Earth and the Moon, and the size of the Earth, and the lives of the personalities involved. The remarkable Jeremiah Horrocks. He was the first observer in 1639 of a transit of Venus to use it to deduce the distance from the Earth to the Sun, using the method of parallax, which is simply explained. The story of Halley’s proposal for the first international collaboration to observe a transit in 1671 and of his life. The adventures and misadventures of those who set out around the globe for this and the later transit observations of 1769, including Captain Cook in Tahiti. These produced the first reasonably accurate dimensions for our solar system.

scholarly journals The chlorine isotope fingerprint of the lunar magma ocean

2015 ◽  
Vol 1 (8) ◽  
pp. e1500380 ◽  
Author(s):  
Jeremy W. Boyce ◽  
Allan H. Treiman ◽  
Yunbin Guan ◽  
Chi Ma ◽  
John M. Eiler ◽  
...  
Keyword(s):  
Solar System ◽  
Isotope Ratios ◽  
Terrestrial Planets ◽  
The Moon ◽  
Magma Ocean ◽  
Chlorine Isotope ◽  
Important Stage ◽  
Lunar Basalts ◽  
Lunar Mare ◽  
Mare Basalts

The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free (“dry”) Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because 37Cl/35Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, 37Cl/35Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high 37Cl/35Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon’s history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets.

scholarly journals Exogeology from Polluted White Dwarfs

Elements ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. 241-244
Author(s):  
Siyi Xu ◽  
Amy Bonsor
Keyword(s):  
Solar System ◽  
White Dwarf ◽  
White Dwarfs ◽  
Planetary Systems ◽  
Terrestrial Planets ◽  
Strong Gravity ◽  
Exoplanetary Systems ◽  
Planetary Bodies

It is difficult to study the interiors of terrestrial planets in the Solar System and the problem is magnified for distant exoplanets. However, sometimes nature is helpful. Some planetary bodies are torn to fragments and consumed by the strong gravity close to the descendants of Sun-like stars, white dwarfs. We can deduce the general composition of the planet when we observe the spectroscopic signature of the white dwarf. Most planetary fragments that fall into white dwarfs appear to be rocky with a variable fraction of associated ice and carbon. These white dwarf planetary systems provide a unique opportunity to study the geology of exoplanetary systems.

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