Mooning over the Dust Rings of Jupiter

By Cowen, Ron | Science News, September 19, 1998 | Go to article overview

Mooning over the Dust Rings of Jupiter


Cowen, Ron, Science News


The deep impacts that killed the dinosaurs or excavated our moon's vast craters count among the most spectacular examples of collisions in the solar system. Even little crashes, however, can make a big difference.

Images taken by the Galileo spacecraft reveal that the dust kicked up by scraps of interplanetary debris plowing into four of Jupiter's tiniest moons are the source of the giant planet's dust rings. Mars' moon Phobos also has been pummeled and its surface pulverized into powder perhaps a meter deep.

Faint rings encircling Jupiter's equator between the planet and its large moon Io were discovered by the two Voyager craft in the late 1970s. The craft revealed a flattened main ring, along with a puffier, inner ring called the halo. The observations also hinted at a third, wispy, outer ring. Galileo images, taken in 1996 and 1997 and released this week, show that the outer ring is in fact two rings, dubbed gossamer rings.

Jupiter's tiny moon Adrastea, only 20 kilometers across, skims the main ring's outer edge, while another small satellite, Metis, lies within the ring. The Galileo pictures confirm that the ring's densest part is the outer edge, adding weight to earlier suspicions that Adrastea feeds the ring. As one of the smallest Jovian moons, Adrastea has weak gravity and stands to lose great amounts of dust during any impacts.

The new pictures show that two other moons, Thebe and Amalthea, each orbit the outer edge of a different gossamer ring and provide the material for them. The halo appears to be made of charged dust particles that are lifted out of the main ring by electromagnetic forces, says Joseph Veverka of Cornell University.

"For the first time we understand why Jupiter has rings and how the rings actually work," he says. Veverka and his colleagues unveiled the Galileo images at a Cornell press briefing.

All four moons appear dark, red, and heavily cratered, indicating that they have been bombarded by meteoroids, which are fragments of asteroids and comets. Correspondingly, the rings contain tiny, reddish particles that resemble dark soot. Galileo viewed the rings almost edge-on, lit from behind by the sun, an arrangement that made micrometer-size particles highly visible.

The angles at which the satellites orbit Jupiter, relative to the planet's equatorial plane, correlate with the vertical extent, or height, of the rings. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Mooning over the Dust Rings of Jupiter
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.