Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Introduction to Astrophysics: Hydrostatic Equilibrium

In course

PHYS-209: Astrophysics I: introduction to astrophysics

Ce cours décrit de façon simple les processus physiques qui expliquent l'univers dans lequel nous vivons. En couvrant une large gamme de sujets, le but du cours est aussi de donner un aperçu général des objets astrophysiques qui nous entourent. ...

Description

This lecture introduces the hydrostatic equilibrium equation for ideal gases, the pressure profile in astrophysics, the mean molecular mass of different planets, and the conditions required for a planet to retain its atmosphere.

In MOOC

Introduction to Astrophysics

Official source

Related concepts (32)

Atmosphere

An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78 %), oxygen (21 %), argon (0.

Planet

A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion. The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth and Mars, and the giant planets Jupiter, Saturn, Uranus and Neptune.

Extraterrestrial atmosphere

The study of extraterrestrial atmospheres is an active field of research, both as an aspect of astronomy and to gain insight into Earth's atmosphere. In addition to Earth, many of the other astronomical objects in the Solar System have atmospheres. These include all the gas giants, as well as Mars, Venus and Titan. Several moons and other bodies also have atmospheres, as do comets and the Sun. There is evidence that extrasolar planets can have an atmosphere.

Planetary science

Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their formation. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history.

Atmosphere of Venus

The atmosphere of Venus is primarily of supercritical carbon dioxide and is much denser and hotter than that of Earth. The temperature at the surface is 740 K (467 °C, 872 °F), and the pressure is , roughly the pressure found underwater on Earth. The Venusian atmosphere supports opaque clouds of sulfuric acid, making optical Earth-based and orbital observation of the surface impossible. Information about the topography has been obtained exclusively by radar imaging. Aside from carbon dioxide, the other main component is nitrogen.

Related lectures (30)

Planetary Atmospheres: Hydrostatic Equilibrium Equation MOOC: Introduction to Astrophysics

Covers the hydrostatic equilibrium equation in planetary atmospheres and conditions for retaining an atmosphere.

Astrophysical Objects: Static Systems

Explores spherically symmetric and static astrophysical objects, including black holes and the modeling of matter.

Sustainable Development Goals: Individual and Collective Actions

Emphasizes the role of individual and collective actions in achieving sustainability through the Sustainable Development Goals and the successes of the Millennium Development Goals.

Thermodynamic Coefficients: Applications MOOC: Thermodynamics I

Explores the practical applications of calorimetric coefficients in thermodynamics, including specific calculations for perfect gases.

Chemical Equilibria and Reactivity