Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Origin Of New Moons Explained

15.05.2003


The ability to understand how small bodies such as moons switch from orbiting the Sun to orbiting a planet has long remained one of the outstanding problems of planetary science. A paper published in Nature on 15 May shows how this problem has been resolved using chaos theory, enabling scientists to predict where astronomers might search for new moons orbiting the giant planets.



In the last couple of years many small moons have been found orbiting the giant planets in our Solar System. For example, Jupiter now has 60 moons in total and Saturn more than 30. Astronomers believe that understanding the nature of these moons can reveal important clues about the early history of the planets. Such insights into understanding our own Solar System will help us understand how other solar systems came into being, and whether they might be favourable to life.

The moons can be divided into two groups - regular and irregular. Regular moons have a roughly circular orbit around their planet and are believed to have been formed there during the early history of the Solar System. Irregular moons have an orbit that is highly elliptical, orbiting the planet at a distance of many millions of miles. These are believed to have originally encircled the Sun and to have been subsequently ’’captured’’ by the planet they now orbit.


The discovery of these new moons has shaken our cherished ways of understanding our Solar System. In particular, the problem of satellite capture - the mechanism by which bodies switch from an orbit around the Sun to an orbit around the planet - remained outstanding. Secondary to this was the problem of why some moons have prograde orbits - revolving in the same direction as the planet - while the vast majority have retrograde orbits.

Stephen Wiggins and Andrew Burbanks, mathematicians at Bristol University, along with David Farrelly and Sergey Astakhov, theoretical chemists at Utah State University, were using chaos theory to understand the mechanics of chemical reactions. They realised that the approach they had been using in chemistry might also be applied to the problem of ’’capture’’. Furthermore, they thought that if they could solve the capture problem it might give them some insight into their chemistry problems.

Stephen Wiggins said: "When we started to look at the capture of irregular moons what we found was that no-one else was trying to understand this problem in three dimensions using chaos theory. Most work was focused on understanding the behaviour of these moons after they had been captured. So in an attempt to understand how a body orbiting the Sun could be brought in to an orbit around one of the giant planets we simulated the ’’switching’’ mechanism. We found that it was chaos that allowed the capture process to take place."

Using the mathematical equations they developed to explain the capture mechanism, the Bristol and Utah research groups present an explanation which not only agrees well with the observed locations of the known irregular moons, but also predicts new regions where moons could be located. The ability to predict where new moons might be found should make life much easier for astronomers who face the daunting task of searching huge regions of space for them.

The joint UK/US research team also showed that the moons initially captured into prograde orbits of moons are not only chaotic, but that they have a tendency to approach the region very close to the planet. This means that they have a greater chance of being eliminated by collisions with the inner giant moons or the planet, thereby explaining the far larger number of retrograde moons, especially around Jupiter.

This work shows that chaos-assisted capture may be a necessary, and quite general, predecessor of certain types of orderly and stable satellite orbits. END

Cherry Lewis | alfa

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>