Shadows and Solar-Lunar Eclipses

SHADOWS ANDSOLAR-LUNAR

ECLIPSES

BY: BOLISLIS, VALERI

WHAT IS A SHADOW?• A shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two dimensional silhouette, or reverse projection of the object blocking the light.The angle of the sun, its apparent height in the sky causes a change in the length of shadows. Low-angles create longer shadows.

WHAT IS AN ECLIPSE?• An eclipse is a natural phenomenon.

Nevertheless, in some ancient and modern cultures, solar eclipses have been attributed to supernatural causes or regarded as bad omens. A total solar eclipse can be frightening to people who are unaware of its astronomical explanation, as the Sun seems to disappear during the day and the sky darkens in a matter of minutes.

WHAT IS AN UMBRA?

• The umbra (Latin: shadow) is the darkest part of a shadow. From within the umbra, the source of light is completely concealed by the occulting body. In astronomy, an observer in the umbra is said to be experiencing a total eclipse. 

WHAT IS A PENUMBRA?

• The penumbra (Latin: paenes "almost, nearly" + umbra "shadow") the region in which only a portion of the occulting body is obscuring the light source. An observer in the penumbra experiences a partial eclipse. 

WHAT IS AN ANTUMBRA?

• The antumbra is the region from which the occulting body appears entirely contained within the disc of the light source. If an observer in the antumbra moves closer to the light source, the apparent size of the occulting body increases until it causes a full umbra. An observer in this region experiences an annular eclipse.

SOLAR ECLPISE

WHAT IS A SOLAR ECLIPSE?

• As seen from the Earth, a solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks ("occults") the Sun. This can happen only at new moon, when the Sun and the Moon are in conjunction as seen from Earth in an alignment referred to as syzygy. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses only part of the Sun is obscured.

4 TYPES OF SOLAR

ECLIPSES

TOTAL ECLIPSE

• Occurs when the dark silhouette of the Moon completely obscures the intensely bright light of the Sun, allowing the much fainter solar corona to be visible. During any one eclipse, totality occurs at best only in a narrow track on the surface of Earth.

ANNULAR ECLIPSE

•  occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the dark disk of the Moon.

HYBRID ECLIPSE ( ANNULAR/TOTAL ECLIPSE)

• Shifts between a total and annular eclipse. At certain points on the surface of Earth it appears as a total eclipse, whereas at other points it appears as annular. Hybrid eclipses are comparatively rare.

PARTIAL ECLIPSE• Occurs when the Sun and Moon are not

exactly in line and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra passes above the Earth's polar regions and never intersects Earth's surface.

LUNAR ECLIP

SE

WHAT IS A LUNAR ECLIPSE?

• A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the Sun, Earth, and Moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a full moon.

3 TYPES OF LUNAR

ECLIPSES

TOTAL LUNAR ECLIPSE

• A total lunar eclipse occurs when the whole moon disappears as it passes through the Earth's umbral shadow. This is when the moon emits very different vibrant colors which are breathtakingly beautiful.

PARTIAL LUNAR ECLIPSE

• A partial lunar eclipse occurs when a portion of the moon passes through the Earth's umbral shadow. This is easy to see and can be viewed by the naked eye without any danger of damage to the eye whatsoever.

PENUMBRAL LUNAR ECLIPSE

•A penumbral eclipse is when the moon passes through the Earth's penumbral shadow, but this is very difficult to see.