its broad component. The broad component is geometrically thicker than the narrow component. This is supported by the observations of a ring plane-crossing event in 2007, when the δ ring remained visible, which is consistent with the behavior of a simultaneously geometrically thick and optically thin ring. γ (gamma) ring The γ ring is narrow, optically dense and slightly eccentric. Its orbital inclination is almost zero. The width of the ring varies in the range 3.6–4.7 km, although equivalent optical depth is constant at 3.3 km. The normal optical depth of the γ ring is 0.7–0.9. During a ring plane-crossing event in 2007 the γ ring disappeared, which means it is geometrically thin like the ε ring and devoid of dust. The width and normal optical depth of the γ ring show significant azimuthal variations. The mechanism of confinement of such a narrow ring is not known, but it has been noticed that the sharp inner edge of the γ ring is in a 6:5 resonance with Ophelia. η (eta) ring The η ring has zero orbital eccentricity and inclination. Like the δ ring, it consists of two components: a narrow optically dense component and a broad outward shoulder with low optical depth. The width of the narrow component is 1.9–2.7 km and the equivalent depth is about 0.42 km, which corresponds to the normal optical depth of about 0.16–0.25. The broad component is about 40 km wide and its equivalent depth is close to 0.85 km, indicating a low normal optical depth of 2 × 10−2. It was resolved in Voyager 2 images. In forward-scattered light, the η ring looked bright, which indicated the presence of a considerable amount of dust in this ring, probably in the broad component. The broad component is much thicker (geometrically) than the narrow one. This conclusion is supported by the observations of a ring plane-crossing event in 2007, when the η ring demonstrated increased brightness, becoming the second brightest feature in the ring system. This is consistent with the behavior of a geometrically thick but simultaneously optically thin ring. Like the majority of other rings, the η ring shows significant azimuthal variations in the normal optical depth and width. The narrow component even vanishes in some places. α (alpha) and β (beta) rings After the ε ring, the α and β rings are the brightest of Uranus's rings. Like the ε ring, they