2007-03-23 03:32:50 · 17 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Friend ,
it is normally used for ''SHADOW''
the other meanings as per dictionary.com are as below.:
1. shade; shadow.
2. the invariable or characteristic accompaniment or companion of a person or thing.
3. Astronomy. a. the complete or perfect shadow of an opaque body, as a planet, where the direct light from the source of illumination is completely cut off..
b. the dark central portion of a sunspot.
4. a phantom or shadowy apparition, as of someone or something not physically present; ghost; spectral image
So those are the meanings of UMBRA.
Hope the information is useful to some extent.
Good luck .
2007-03-23 03:47:09 · answer #1 · answered by Radhakrishna( prrkrishna) 7 · 0⤊ 0⤋
The umbra ("shadow" in Latin) is the darkest part of a shadow. From within the umbra, the source of light is completely blocked by the object causing the shadow. This contrasts with the penumbra, where the light source is only partially blocked and there is only a partial shadow.
Penumbras occur only when the source of light is not a point source. As the sun is a visible disc, solar shadows have penumbras.
The part of the penumbra where an annular eclipse is visible is called the antumbra. In an annular eclipse, the moon is not of sufficient size to completely cover the sun, and so its shadow is not long enough to reach the Earth and result in a total solar eclipse. At maximum eclipse, the moon is surrounded by a ring, or annulus, of light, and the location on Earth where the ring can be seen is also the location of the antumbra. Although the antumbra may be referred to as a "negative shadow", it is nevertheless darker than the penumbra, just like the umbra is in a total eclipse. However, whereas the umbra is completely devoid of sunlight, the antumbra is not because of the remaining ring.
2007-03-23 20:11:13 · answer #2 · answered by cyberkrishnan 2 · 0⤊ 0⤋
I think surez's answer above pretty much explains it. However there is one more tiny detail....
Umbras and penumbras usually have something to do with eclipses. A complete solar eclipse occurs when the umbra of the moons shadow falls on the earth-hopefully somewhere inhabited. The regions where the penumbra falls will have partial eclipses. The same thing happens with lunar eclipses too except that the earth's shadow-penumbra or the umbra falls on the moon. If the Earth's umbra falls on the moon, it will be totally invisible whereas if the penumbra falls the moon will turn a dull bood red. In ancient times this was interpreted as a bad/good omen in various cultures.
2007-03-23 10:47:43 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The umbra (Latin: "shadow") is the darkest part of a shadow. From within the umbra, the source of light is completely blocked by the object causing the shadow. This contrasts with the penumbra, where the light source is only partially blocked and there is only a partial shadow.
Penumbras occur only when the source of light is not a point source. As the sun is a visible disc, solar shadows have penumbras.
2007-03-23 10:37:16 · answer #4 · answered by surez 3 · 1⤊ 0⤋
The umbra is the dark part of the shadow, e.g., the Earth's shadow on the Moon during a lunar eclipse, or the Moon's shadow on the Earth during a solar eclipse. See http://www.hermit.org/Eclipse/why_lunar.html
2007-03-23 10:38:27 · answer #5 · answered by Astronomer1980 3 · 0⤊ 0⤋
Umbra (Latin) A shade; the kama-rupic spook which remains in the lower regions of the astral light after physical death and often hovers in the neighborhood of the tomb. "The ancient Latin races . . . believed that after death Anima, the pure divine soul, ascended to heaven, a place of bliss; Manes (the Kama Rupa) descended into Hades (Kama Loka); and Umbra (or astral double, the Linga Sharira) remained on earth hovering about its tomb, because the attraction of physical, objective matter and affinity to its earthly body kept it within the places which that body had impressed with its emanations. Therefore, they said that nothing but the astral image of the defunct could be seen on earth, and even that faded out with the disintegration of the last particle of the body which had been so long its dwelling" (TG 353).
2007-03-23 10:39:34 · answer #6 · answered by Abu Alnour 1 · 0⤊ 0⤋
Umbra is the dark shaded portion of a shadow while Penumbra is the lighter shaded portion of a shadow.
2007-03-24 03:46:27 · answer #7 · answered by coolgurl 2 · 0⤊ 0⤋
the region of the shadow which experiences total darkness is called umbra.
2007-03-24 12:53:46 · answer #8 · answered by manarshh_jot 2 · 0⤊ 0⤋
um·bra (Åm'brÉ)
n., pl. -bras or -brae (-brÄ)
A dark area, especially the blackest part of a shadow from which all light is cut off. See synonyms at shade.
Astronomy.
The completely dark portion of the shadow cast by the earth, moon, or other body during an eclipse.
The darkest region of a sunspot..
2007-03-23 12:38:25 · answer #9 · answered by Anonymous · 0⤊ 0⤋
Umbra and penumbra are commonly used to denote shadow and partial shadow, when describing eclipse phenomenon! (solar and lunar)
2007-03-23 10:44:53 · answer #10 · answered by swanjarvi 7 · 0⤊ 0⤋