even if something is invisible can the sun's light on it, still cast a shadow? i know that invisible cloak technology being developed today involves bending light, how does that factor into shadows?
2006-06-21 10:55:04 · 11 answers · asked by Riddler 5 in Science & Mathematics ➔ Physics
ok, what if an invisible plane flew over my head, would there be a shadow?
2006-06-22 01:18:15 · update #1
i saw many good answers to this question but none of them address your question from a theoretical standpoint.
1. the question of whether "something" ( or any physical entity ) casts a shadow is irrelevant to us being able to "see" the shadow or the entity ( which is what many of the other questions address ).
2. therefore, consider a single atom or molecule. it "exists" in space ( but is invisible ) and when it is subject to light ( a stream of photons ), it WILL alter their paths. ( no question )
3. a shadow is defined as a variation in the intensity of light cast by an object. any alteration from the original pattern of photons caused by these atoms CAN be measured ( on a surface or other medium ( film etc ))
4. this ALTERATION is a shadow in essence.
5. whether or not the object or the shadow is visible to the naked eye is NOT the issue. ( people with poor vision cant see many things and microscopes ( as well as other instruments ) enable us to see many other things.)
5. the FACT is that any material entity ( i.e atom or collection of atoms ) alters light and its trajectory whether we see it or not with our own eyes.
the answer to your question is that every "something" ( that you call it ) ALWAYS has a shadow because it EXISTS ( irrelevant to it being invisible or not due the technology ( cloak ) you spoke about ). its just a matter of measuring the "subtle" shadows with the relevant instruments.
2006-06-21 14:16:25 · answer #1 · answered by fullbony 4 · 2⤊ 3⤋
The "shadow" produced by things like heat and glass comes from the glass/heat/etc having a different index of refraction that the air, so the light bends and produces a different pattern of dark and light interference on the other side of the material. Traditional shadows are caused by an obstruction of light, so an invisible material would not produce a shadow, but there might be anomalies in light where it passed through the material.
2006-06-21 18:23:16 · answer #2 · answered by Monotonous_J 3 · 0⤊ 0⤋
Sort of... depending on your definition of "invisible" and "shadow"...and the shadow of something invisible has been photographed!
Air is invisible, right? A shadow is just the image produced on a surface when light is reflected/absorbed/ or refracted by the object, right? Well, air has had its "shadow" captured in photographs - at least when its density changes.
Scientists have able to photograph "shadows" produced in air by moving objects such as jets, bullets, etc. for a long time. It is called Schlieren photography. Here's how it works.
When an object passes through air at high speed, it causes a pressure (or shock) wave - essentially compressing air immediately in front of it and then creating a "rarefaction" or low pressure zone as the pressure waves propagate.
When air's density changes, its refractive index changes.
When light passes through these regions where the refractive index changes, it refracts the light differently in those regions, causing dark and light patterns when the light reaches the film.
This also works when the refractive index changes because of heating the air.
2006-06-21 20:19:52 · answer #3 · answered by volume_watcher 3 · 0⤊ 0⤋
The invisible cloak technology uses methods to reroute light around objects. This gives the appearance of invisibility. It doesn't make the object translucent. Therefore, depending on the intensity of the light source shadows are possible.
2006-06-21 18:54:08 · answer #4 · answered by that'sBS 3 · 0⤊ 0⤋
I would have to say it depends on the out come. If the item that is invisible is transparent, then no there would not be a shadow. But if it were translucent, then yes there may be one. Think of a window. It's transparent, completely see through with no shadow. However if it's translucent it's not completely clear thus causing a shadow.
2006-06-21 18:59:39 · answer #5 · answered by Legs0891 2 · 0⤊ 0⤋
Yes-- invisible means that you can't see it, so it doesn't interact with visible light. That doesn't mean anything about its interaction with other regions of the spectrum. It could very well be opaque to ultraviolet or infrared light. So, it could cast a shadow in a region of the spectrum that we can't see.
2006-06-22 10:44:10 · answer #6 · answered by wherearethetacos 3 · 0⤊ 0⤋
It depends upon the definition of shadow.
2006-06-21 23:09:51 · answer #7 · answered by Pearlsawme 7 · 0⤊ 0⤋
no it will not cast a shadow, the light has to have something to hit.
2006-06-21 17:58:51 · answer #8 · answered by chuckleslovesjesus 3 · 0⤊ 0⤋
i dont think so, because something would have to be blocking the sun, and something invisible the sun would just shine right through!
2006-06-21 17:59:32 · answer #9 · answered by lp_fan925 1 · 0⤊ 0⤋
well, heat has a shadow, and you can't see that.
2006-06-21 17:58:29 · answer #10 · answered by c_c_runner88 3 · 0⤊ 0⤋