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Accretion Processes  

Alessandro Morbidelli

Online publication date:
Jul 2018
In planetary science, accretion is the process in which solids agglomerate to form larger and larger objects, and eventually planets are produced. The initial conditions are a disc of gas ... More

Active Asteroids  

Henry Hsieh

Online publication date:
Feb 2020
Small Bodies
The study of active asteroids is a relatively new field of study in Solar System science, focusing on objects with asteroid-like orbits but that exhibit comet-like activity. This field, ... More

Agreement on the Rescue and Return of Astronauts and Objects Launched into Outer Space  

Irmgard Marboe

Online publication date:
Jun 2019
Space Law
The Agreement on the Rescue and Return of Astronauts and the Return of Objects Launched into Outer Space (ARRA) of 1968 deals with the obligation of states toward astronauts in distress or ... More

A Selective History of the Jet Propulsion Laboratory  

James D. Burke and Erik M. Conway

The Jet Propulsion Laboratory (JPL) of the California Institute of Technology had its origins in a student project to develop rocket propulsion in the late 1930s. It attracted funding from ... More

Astrology in Ancient Greek and Roman Culture  

Nicholas Campion

Online publication date:
May 2019
Astrology was a central feature of Greek and Roman culture. A knowledge of astrology’s claims, practices, and world view is essential for a full understanding of religion, politics, and ... More

Atmospheric Circulation on Venus  

Masaru Yamamoto

Online publication date:
Mar 2019
Venus is a slowly rotating planet with a thick atmosphere (~9.2 MPa at the surface). Ground- and satellite-based observations have shown atmospheric superrotation (atmospheric rotation much ... More

Atmospheric Electricity in the Solar System  

Karen Aplin and Georg Fischer

Online publication date:
Feb 2019
Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and ... More

Austrian National Space Law  

Cordula Steinkogler

Space Law
This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article. The ... More

Business, Legal, and Policy Issues in Relation to Increased Private Space Activity  

Mark J. Sundahl

Online publication date:
Mar 2019
Throughout the history of human activity in outer space, the role of private companies has steadily grown, and, in some cases, companies have even replaced government agencies as the ... More

Chemical Weathering on Venus  

Mikhail Zolotov

Online publication date:
Aug 2019
Chemical and phase compositions of the surface of Venus could reflect a history of gas–rock and fluid–rock interactions, recent and past climate changes, and a loss of water from the ... More

Clouds in the Martian Atmosphere  

Anni Määttänen and Franck Montmessin

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. ... More


Leonid V. Ksanfomality

Online publication date:
Nov 2018
Small Bodies
Cometary nuclei are small, despite the cosmic scale of the comet tails that they produce. The nuclei have the ability to create rarefied atmospheres, extending as a tail to giant distances ... More

Composition and Chemistry of the Neutral Atmosphere of Venus  

Ann Carine Vandaele

Online publication date:
May 2020
The atmosphere of Venus is quite different from that of Earth: it is much hotter and denser. The temperature and pressure at the surface are 740 K and 92 atmospheres respectively. Its ... More

Depictions of the Moon in Western Visual Culture  

Jay M. Pasachoff and Roberta J.M. Olson

Online publication date:
Jun 2019
Since the landmark lunar landing of Apollo 11 on July 20, 1969, NASA’s Lunar Reconnaissance Orbiter (launched in 2009), and the Japanese Aerospace Exploration Agency’s Kaguya spacecraft ... More

Detection and Characterization Methods of Exoplanets  

Nuno C. Santos, Susana C.C. Barros, Olivier D.S. Demangeon, and João P. Faria

Is the Solar System unique, or are planets ubiquitous in the universe? The answer to this long-standing question implies the understanding of planet formation, but perhaps more relevant, ... More

Dust Devils on Earth and Mars  

Matthew R. Balme

Online publication date:
May 2019
Dust devils are rotating columns or cones of air, loaded with dust and other fine particles, that are most often found in arid or desert areas. They are common on both Mars and Earth, ... More

Evolution of the Martian Crust  

John C. Bridges

This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article. Mars, ... More

Exoplanets: Atmospheres of Hot Jupiters  

Dmitry V. Bisikalo, Pavel V. Kaygorodov, and Valery I. Shematovich

The history of exoplanetary atmospheres studies is strongly based on the observations and investigations of the gaseous envelopes of hot Jupiters—exoplanet gas giants that have masses ... More

Extraterrestrial Resources  

V.V. Shevchenko

Since the early 1990s, in analytical reviews, experts have increasingly been paying attention to the growing scarcity of rare and rare earth metals (REM) necessary for the development of ... More

The Formation of the Martian Moons  

Pascal Rosenblatt, Ryuki Hyodo, Francesco Pignatale, Antony Trinh, Sebastien Charnoz, Kevin Dunseath, Mariko Dunseath-Terao, and Hidenori Genda

The origin of the natural satellites or moons of the solar system is as challenging to unravel as the formation of the planets. Before the start of the space probe exploration era, this ... More