Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Escape Velocity01:26

Escape Velocity

5.9K
The escape velocity of an object is defined as the minimum initial velocity that it requires to escape the surface of another object to which it is gravitationally bound and never to return. For example, what would be the minimum velocity at which a satellite should be launched from the Earth's surface such that it just escapes the Earth's gravitational field?
To calculate the escape velocity, it is assumed that no energy is lost to any frictional forces. In practice, a satellite...
5.9K
Escape Velocities of Gases01:19

Escape Velocities of Gases

1.1K
To escape the Earth's gravity, an object near the top of the atmosphere at an altitude of 100 km must travel away from Earth at 11.1 km/s. This speed is called the escape velocity. The temperature at which gas molecules attain the rms speed, which is equal to the escape velocity, can be estimated by using the equation for the average kinetic energy of the gas molecules. According to the kinetic theory of gas, the average kinetic energy of the gas molecules is proportional to its...
1.1K
Density and Archimedes' Principle01:05

Density and Archimedes' Principle

8.0K
When a lump of clay is dropped into water, it sinks. But if the same lump of clay is molded into the shape of a boat, it starts to float. Because of its shape, the clay boat displaces more water than the lump and experiences a greater buoyant force, even though its mass is the same. The same holds true for steel ships. The average density of an object majorly determines if the object will float. If an object's average density is less than that of the surrounding fluid, it will float. The...
8.0K
Archimedes' Principle01:13

Archimedes' Principle

9.9K
Archimedes' principle states that an upward buoyant force exerted on a body that is immersed partially or entirely in a fluid is equal to the weight of the fluid displaced by it. To understand how much buoyant force is needed to make an object float, let us think about what happens when a submerged object is removed from a fluid. If the object were not in the fluid, the space occupied by the object would be filled by the fluid having a weight wfl. This weight is supported by the...
9.9K
Variation in Acceleration due to Gravity near the Earth's Surface01:20

Variation in Acceleration due to Gravity near the Earth's Surface

2.6K
An object's apparent weight is its weight measured by a spring balance at its location. It is different from its true weight, the force with which the Earth pulls it, because of the Earth's rotation. Mathematically, an object's apparent weight equals its true weight minus the centripetal force that keeps it in a circular motion along with the Earth's surface every 24 hours.
The difference between the true and apparent weights is proportional to the square of the Earth's...
2.6K
Gravity between Spherical Bodies01:27

Gravity between Spherical Bodies

8.9K
Newton's law of gravitation describes the gravitational force between any two point masses. However, for extended spherical objects like the Earth, the Moon, and other planets, the law holds with an assumption that masses of spherical objects are concentrated at their respective centers.
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
8.9K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Titan's strong tidal dissipation precludes a subsurface ocean.

Nature·2025
Same author

Endogenic heat at Enceladus' north pole.

Science advances·2025
Same author

Thermal asymmetry in the Moon's mantle inferred from monthly tidal response.

Nature·2025
Same author

Titan's spin state as a constraint on tidal dissipation.

Science advances·2025
Same author

Tidally driven remelting around 4.35 billion years ago indicates the Moon is old.

Nature·2024
Same author

Io's tidal response precludes a shallow magma ocean.

Nature·2024

Related Experiment Video

Updated: Nov 10, 2025

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation
09:49

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation

Published on: November 18, 2015

12.5K

Explaining the Galilean Satellites' Density Gradient by Hydrodynamic Escape.

Carver J Bierson1, Francis Nimmo1

  • 1Department of Earth and Planetary Sciences, UC Santa Cruz, 1156 High St, Santa Cruz, CA 95064, USA.

The Astrophysical Journal. Letters
|April 2, 2021
PubMed
Summary

Vapor loss during moon formation explains the Galilean satellites' density trend. This process also predicts distinct D/H ratios for Europa, offering testable predictions for future missions.

More Related Videos

Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite
07:00

Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite

Published on: March 11, 2020

7.6K
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

8.8K

Related Experiment Videos

Last Updated: Nov 10, 2025

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation
09:49

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation

Published on: November 18, 2015

12.5K
Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite
07:00

Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite

Published on: March 11, 2020

7.6K
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

8.8K

Area of Science:

  • Planetary Science
  • Astrobiology
  • Geophysics

Background:

  • The Galilean satellites show a density decrease with distance from Jupiter, a trend debated for decades.
  • Formation theories include background conditions, accretion processes, and tidal heating.
  • Previous explanations have not fully accounted for the observed density gradient.

Purpose of the Study:

  • To investigate the role of vapor loss driven by accretional heating in shaping Galilean satellite densities.
  • To explain the monotonic density decrease with distance from Jupiter.
  • To predict isotopic signatures resulting from this formation process.

Main Methods:

  • Utilized a model incorporating vapor loss driven by accretional heating.
  • Simulated satellite formation with accretion timescales of approximately 300 kyr.
  • Analyzed the impact of vapor escape on water inventories and isotopic fractionation.

Main Results:

  • Vapor loss during accretion successfully reproduces the observed density trend of the Galilean satellites.
  • Io and Europa likely had early surface liquid water oceans, with significant water loss.
  • Europa is predicted to have a higher D/H ratio than Ganymede and Callisto due to isotopic fractionation.

Conclusions:

  • Vapor loss driven by accretional heating is a key process in Galilean satellite formation.
  • This mechanism explains both the density trend and the differing water inventories.
  • Predicted D/H ratios offer testable hypotheses for missions like Europa Clipper.