The Satellites of Uranus

By Daniel Zimmermann

What are the names of the moons of Uranus? How were they discovered? What are the names of their craters and other physical features? These are some of the questions that are answered in this interesting e-book.

• Language: English
• Publisher: Lulu.com
• Release date: Mar 3, 2019
• ISBN: 9780359478200

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The Satellites of Uranus

The Satellites of Uranus

By Daniel Zimmermann

The Rings of Uranus

Discovery of the Ring System

William Herschel claimed that Uranus had a ring, and his description matches what is now called the ε ring. Rightly or wrongly, his contribution to the discovery of the Uranian rings is not recognized - at least not yet.

In 1877, James Elliot, Edwin Dunham, and Douglas Mink were studying the atmosphere of Uranus as it passed in front of a star, Unexpectedly, the light of the star dimmed several times as it draw near the planet. After passing behind Uranus, the star again dimmed several times as it receded from the planet. They concluded that Uranus had rings. They counted five rings, but the NASA website claims that they must have missed some on account of the excitement of the discovery. (When I speak of the star passing behind the planet, I am using phenomenal language, of course. It was actually the planet that moved, not the star.)

Eventually it was discovered that Uranus had at least 13 rings. Voyager 2 and the Hubble Space Telescope detected some of these additional rings.

Names of the Rings

Astronomers have used Greek letters as designations of most of the rings of Uranus. A few are identified by numerals.

The closest ring to Uranus is called ζ (the Greek letter zeta). Next come three rings designated by the Arabic numerals 6, 5, and 4. Proceeding outward, we arrive at rings called α (alpha), β (beta), η (eta), γ (gamma), δ (delta), λ (lambda), ε (epsilon), ν (nu), and finally μ (mu).

Composition of Rings

The rings are composed of small bodies that revolve around the planet Uranus. Their orbits are nearly circular but more eccentric than the rings of Jupiter and Saturn. The planes of their orbits lie close to the plane of the equator of Uranus. The outer ν and μ rings are thought to contain tiny particles in the micrometer range. The other rings also contain a little dust, but their particles are usually more than a meter in diameter, according to the Oxford Dictionary of Astronomy.

The materials in the rings are darker than the corresponding particles in the rings of Saturn. Their chemical components are not yet known.

Orientation of the