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Umbra, penumbra and antumbra of Earth and images that could be seen at some points in these areas (Note: the relative size and distance of the bodies shown are not to scale.)“… The Earth’s shadow has two distinct parts,… the UMBRA is the part of the shadow where all direct sunlight is blocked by the Earth; the PENUMBRA of the shadow is ...
The sun casts shadows that change dramatically through the day. The length of a shadow cast on the ground is proportional to the cotangent of the sun's elevation angle—its angle θ relative to the horizon. Near sunrise and sunset, when θ = 0° and cot(θ) = ∞, shadows can be extremely long.
Earth's shadow (or Earth shadow) is the shadow that Earth itself casts through its atmosphere and into outer space, toward the antisolar point. During the twilight period (both early dusk and late dawn ), the shadow's visible fringe – sometimes called the dark segment or twilight wedge [ 1 ] – appears as a dark and diffuse band just above ...
The shadow of Earth on the Moon during a lunar eclipse is always a dark circle that moves from one side of the Moon to the other (partially grazing it during a partial eclipse). The only shape that casts a round shadow no matter which direction it is pointed is a sphere, and the ancient Greeks deduced that this must mean Earth is spherical. [8]
Photographs of the Moon at different elevations also show that its size remains the same. A simple way of demonstrating that the effect is an illusion is to hold a small pebble (say, 0.33 inches or 8.4 millimetres wide) at arm's length (25 inches or 64 centimetres) with one eye closed, positioning the pebble so that it covers (eclipses) the ...
Self shadows define the volume and texture of an object; cast shadows help define space. [20] The lightest part of the shadow is the "umbra" and the darkest part is the "penumbra". The shape and appearance of the shadow depends on the size and distance of the light source: the most pronounced shadows are from small or distant sources, while a ...
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A Brocken spectre within glory rings. A Brocken spectre (British English; American spelling: Brocken specter; German: Brockengespenst), also called Brocken bow, mountain spectre, or spectre of the Brocken is the magnified (and apparently enormous) shadow of an observer cast in mid air upon any type of cloud opposite a strong light source.