"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light source
above.) Assuming one can create an object which neither reflects nor emits
visible light, what you would see (with normal vision) would be a blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

Sue... wrote:
Mucho Grande wrote:
Sue... wrote:
Mucho Grande wrote:
Sue... wrote:
Mucho Grande wrote:
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

Indeed it is:


http://farside.ph.utexas.edu/teaching.html
http://web.mit.edu/8.02t/www/802TEAL...ight/index.htm

Sue...

thanks for your feedback, but your links are EM links, which
is an oversimplification

Maybe this is more your speed:

Now, does not the prize to Einstein imply
that the Academy recognised the particle
nature of light? The Nobel Committee says
that Einstein had found that the energy exchange
between matter and ether occurs by atoms emitting
or absorbing a quantum of energy,hv .

As a consequence of the new concept of light quanta
(in modern terminology photons) Einstein proposed the
law that an electron emitted from a substance by
monochromatic light with the frequency has to have
a maximum energy of E=hv-p, where p is the energy needed to
remove the electron from the substance. Robert Andrews
Millikan carried out a series of measurements over a
period of 10 years, finally confirming the validity of this
law in 1916 with great accuracy. Millikan had, however,
found the idea of light quanta to be unfamiliar and strange.

The Nobel Committee avoids committing itself to the
particle concept. Light-quanta or with modern terminology,
photons, were explicitly mentioned in the reports on
which the prize decision rested only in connection with
emission and absorption processes. The Committee says
that the most important application of Einstein's photoelectric
law and also its most convincing confirmation has come from
the use Bohr made of it in his theory of atoms, which explains
a vast amount of spectroscopic data.
http://nobelprize.org/physics/articl...ong/index.html

http://nobelprize.org/physics/laurea...n-lecture.html

Sue...

does the object exists or not?

You seem to be entertaining the notion that your
furniture vainishes when you turn off the lights
in the room. I suggest you design an experiment
to test your notions.

Sue...

dear Sue

this is not the same

invisibility doesnt mean dark rooms

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light source
above.) Assuming one can create an object which neither reflects nor emits
visible light, what you would see (with normal vision) would be a blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

dear Howard

a dark spot is visible

imagine a cat able to see both visible and UV spectrum

Sorcerer wrote:
"Mucho Grande" wrote in message oups.com...
|i though i understod light, but this is wird, maybe
| i forget the explanation, her it comes

*plonk*

What is it?

Bill Hobba wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

No entirely transparent object exists.

Bill

Dear Mister Bill

thank you for your feedback, i think you are right

could you elaborate a bit?

the other posters just said that the object still exists




wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

No entirely transparent object exists.

Bill


wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light source
above.) Assuming one can create an object which neither reflects nor emits
visible light, what you would see (with normal vision) would be a blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

and what makes you think that UV spectrum would
block for light in visible spectrum, it doesnt happen in
nature

then why dark and not completly enlightened

"Mucho Grande" wrote in message
oups.com...

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light
source
above.) Assuming one can create an object which neither reflects nor
emits
visible light, what you would see (with normal vision) would be a
blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that
when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

dear Howard

a dark spot is visible


That depends on your definition of "visible". In an LCD crystal, such as in
a calculator or watch, the crystal is not visible. What you are seeing is
NOT the crystal. The light that would normally reflect off or pass through
the clear crystal is scattered, resulting in darkness when viewed from
"above".

imagine a cat able to see both visible and UV spectrum


And... ?

Explain to me how the light from the table beneath the object would reach
your eyes simply because the object neither emits nor reflects light in the
visible spectrum? If no such light reaches your eyes, then what you "see"
there will be nothing but darkness. There has to be a path for that light
from the table to your eyes.

You'd need something transparent, which you've said isn't what you mean.
You also said a transparent object would be visible. That's not true. If
it were 100% transparent, light would pass right through it. Everyday
experience is with objects which are not completely transparent. Either
they have imperfections, are less than 100% transparent, or they emit or
reflect enough light to make them visible.

Sounds like the question boils down to: is it possible for an object to be
100% transparent? In a limited spectrum, under certain constraints (such as
direction of viewing, perhaps), it should be possible to get arbitrarily
close to 100% transparency. (The Army is working on just such an
"invisibility cloak" technology right now. And I'm betting they're pretty
sure that just making a soldier invisible isn't going to also make him cease
to exist.)

You could take a logical point of view of this as well. You are describing
an object. Therefore, the object must exist (at least in your hypothetical
world). If it exists, then how can you ask "does it exist"? The assumption
states the conclusion.

If you're asking "is it posible for such an object to exist?", then see the
paragraph above. Or get a good book on optics, which aren't exactly my
field. :-)

-Howard

"Mucho Grande" wrote in message
ups.com...

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light
source
above.) Assuming one can create an object which neither reflects nor
emits
visible light, what you would see (with normal vision) would be a
blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that
when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

and what makes you think that UV spectrum would
block for light in visible spectrum, it doesnt happen in
nature

then why dark and not completly enlightened


I can't tell if I'm having more trouble understanding your logic, or your
English. What are you talking about?

Who said anything about "UV spectrum" blocking the "visible spectrum"? I'm
talking about an object. If light simply passes through the object, then it
is by definition transparent, in whatever spectrum you choose. Yet you
stated you did not mean a transparent object.

So which is it?

-Howard

Howard wrote:
"Mucho Grande" wrote in message
oups.com...

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light
source
above.) Assuming one can create an object which neither reflects nor
emits
visible light, what you would see (with normal vision) would be a
blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that
when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

dear Howard

a dark spot is visible


That depends on your definition of "visible". In an LCD crystal, such as in
a calculator or watch, the crystal is not visible. What you are seeing is
NOT the crystal. The light that would normally reflect off or pass through
the clear crystal is scattered, resulting in darkness when viewed from
"above".

imagine a cat able to see both visible and UV spectrum


And... ?

Explain to me how the light from the table beneath the object would reach
your eyes simply because the object neither emits nor reflects light in the
visible spectrum?

you use words and say nothing

the object doesnt disturb the visible spectrum, does it helps?

If no such light reaches your eyes, then what you "see"
there will be nothing but darkness. There has to be a path for that light
from the table to your eyes.

if the objects blocks for the light, you said darkness, then it will be
a visible black body object


You'd need something transparent, which you've said isn't what you mean.

no, i dont need that

You also said a transparent object would be visible. That's not true. If
it were 100% transparent, light would pass right through it. Everyday
experience is with objects which are not completely transparent. Either
they have imperfections, are less than 100% transparent, or they emit or
reflect enough light to make them visible.

so i was right


Sounds like the question boils down to: is it possible for an object to be
100% transparent? In a limited spectrum, under certain constraints (such as

no, the question is simple

is an object only visible outside the visible
spectrum existent?

direction of viewing, perhaps), it should be possible to get arbitrarily
close to 100% transparency. (The Army is working on just such an
"invisibility cloak" technology right now. And I'm betting they're pretty
sure that just making a soldier invisible isn't going to also make him cease
to exist.)

You could take a logical point of view of this as well. You are describing
an object. Therefore, the object must exist (at least in your hypothetical
world). If it exists, then how can you ask "does it exist"? The assumption
states the conclusion.

your tongue speeks bifurcated

can such an object exist, if not visible in the visible light psectrum?


If you're asking "is it posible for such an object to exist?", then see the
paragraph above. Or get a good book on optics, which aren't exactly my
field. :-)

what paragraph, you didnt answered nor argumented the question


-Howard

i do a lot of optics everyday, i dont need books