A friend and I were watching atlantis and he ask me "If they are cloaked then would there be a shadow". So help us out on this one.
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To become invisible, an object must do two things: it has to be able to bend light around itself, so that it casts no shadow, and it must produce no reflection. Bending light around an object requires a material to have a negative refractive index. The refractive index is a property that dictates how light passes through a medium; it's the reason a stick will look bent when placed in water. If water had a negative refractive index, it would make the stick look as though it were bending back on itself. Does that answer your question? I could go on and extrapolate on how our eye perceives things but do not want to confuse you
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There is a huge misconception around this "invisible" word. Many debate, and I am amongst them, that NOT VISIBLE is a better word. The object is there, but light is bent around it...so it is not invisibility per se ...
Baccalaureate Physics. I had an exam on this . Used to love this stuff with snell's law, etc, etc 
. So long ago..shame I forgot some things 
Last edited by Integrabyte; 20 April 2008, 03:00 AM. -
this should help
Spoiler:
The answer is no as light is bet around it, but in an atmosphere which contains things like water vapor in the air you can perceive the jumper's outline, if you look carefully and at a close enough distance. Also you can hear the hum of the engines while in an atmosphere. Incredibly hard to track but it is possible in certain situations.
In space both of those weaknesses are non existent.Comment
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In addition to bending light around itself, a ship could cloak itself by phasing out of alignment with normal matter (Merlin's device) or by altering its material to become transparent to light (we've never seen this, and it probably wouldn't work worth a damn... you can still see glass pretty easily from the right angle).
Of course, the negative refractive index is by far the method most sanely rooted in the world of real physics. "Phasing out of alignment" is one of those sci-fi things that pops up in many different shows but is about as realistic as transporters/teleporters.Comment
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The short answer is NO. If it would cast shadows then it wouldn't be very effective now would it? And I agree with integrabyte, Invisible would mean that something canot be seen under any circumstances, but you would be able to see where the jumpers are if you accidentaly splashed some water at it...So Not Visible is more acurate, since you usually don't see it, but if you would know it is there you could easily detect it...I don't know if any of this made any sense though...
May I ask you something? Do you mean the IB-program(International Baccalaureate) in High School(I think that high school is equivalent to what is called "Gymnasium" in sweden)? That's what I'm studying at the moment.Originally posted by Integrabyte View PostBaccalaureate Physics.
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IB Higher Level Physics ExamOriginally posted by SG-Kamikaze View PostThe short answer is NO. If it would cast shadows then it wouldn't be very effective now would it? And I agree with integrabyte, Invisible would mean that something canot be seen under any circumstances, but you would be able to see where the jumpers are if you accidentaly splashed some water at it...So Not Visible is more acurate, since you usually don't see it, but if you would know it is there you could easily detect it...I don't know if any of this made any sense though...
May I ask you something? Do you mean the IB-program(International Baccalaureate) in High School(I think that high school is equivalent to what is called "Gymnasium" in sweden)? That's what I'm studying at the moment.. If memory serves I had it on Paper 2 which is the killer one with very long questions .
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light bends around it like a rock in a river there is no shadow, optically it is if there is nothing there. Physically that is quite evident.Their white flags are no match to our guns!!
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If light is bent around the cloaked object so that nobody outside it can see it, then why can the people inside the cloak see anything outside?
If they light has been bent around, then no light should reach the people's eyes and they should be seeing blackness when they try to look out.
What happens when people inside a cloak shine light outside?
Is the light visible?What's the deal with the retardedly huge sigs?!
Spelling correction by Gen Blue
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it is a tvshow, anything can happen there
the new rickroll by the way mcrolld:
http://youtube.com/watch?v=3GqJgiZtdEU&feature=relatedComment
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I'm in Pre-IB at the moment and I'm starting IB1 Next year, but unfortually I can't chose Physics...Our school doesn't have a teacher that is qualified to teach Physics in English...=/Originally posted by Integrabyte View PostIB Higher Level Physics Exam. If memory serves I had it on Paper 2 which is the killer one with very long questions .
Spoiler:Comment
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=/ Yeah, I wanted to have it but since we didn't have the teacher I had to take the swedish version Physics A, which is sort of an easy version of Standard level...Originally posted by Integrabyte View PostComment
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Love a good on topic threadOriginally posted by SG-Kamikaze View Post
Anyway if light is bending around something the logically the shadow wouldnt be therePerhaps PuffComment
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hang on if im right you wont be able to see the shaddow but wouldnt you beable to see the massive curve in the water where atlantis is sitting?Comment
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no you can't see the curve.
Diagram:
Path of light: l
cloaked ship: S
uncloaked ship: T
.A
.l l
.l l
.T
.T
.T
.l l
.l l
.B
.A
.l l
.l l
/S\
l S l
\S/
.l l
.l l
.B
When the ship is cloaked A and B see each other, when the ship is not cloaked they both see the ship. An interesting thing happens when we include a third ship C, in this case 'a' and 'b' will be where C sees A and B as being.
..A ..a
..l l /
..l l/
./S\
C S l
.\S/
..l l\
..l l \
..B ..b
As long as your smart you can notice there is a ship-sized area of space that you can't see but has gravitational and magnetic fields around it.Last edited by Splitsecond; 23 April 2008, 09:41 AM.Comment
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